修改 JavaDoc。

.gitignore

@@ -12,6 +12,8 @@ target
 *.iws
 *.log
 .idea
-
 *.conf
 *.PNG
+
+.vscode/
+*.class

HISTORY

@@ -1,3 +1,8 @@
+Version 1.30  2023-01-29
+  * support tracker server fail over
+    If the tracker server is not specified, when the tracker server fails to
+    get the connection, it will try to get the connection from other tracker servers.
+    The maximum number of attempts is the number of tracker servers minus 1
 
 Version 1.29  2020-01-03
   * support active test for connection pool.

README.md

@@ -26,7 +26,7 @@ mvn install:install-file -DgroupId=org.csource -DartifactId=fastdfs-client-java
 <dependency>
     <groupId>org.csource</groupId>
     <artifactId>fastdfs-client-java</artifactId>
-    <version>1.29-SNAPSHOT</version>
+    <version>1.30-SNAPSHOT</version>
 </dependency>
 ```
 

pom.xml

@@ -4,7 +4,7 @@
 
   <groupId>org.csource</groupId>
   <artifactId>fastdfs-client-java</artifactId>
-  <version>1.29-SNAPSHOT</version>
+  <version>1.30-SNAPSHOT</version>
   <name>fastdfs-client-java</name>
   <description>fastdfs client for java</description>
   <packaging>jar</packaging>
@@ -14,8 +14,8 @@
     <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
     <maven.test.failure.ignore>true</maven.test.failure.ignore>
     <maven.test.skip>true</maven.test.skip>
-    <jdk.version>1.6</jdk.version>
-    <slf4j.version>1.7.26</slf4j.version>
+    <jdk.version>1.8</jdk.version>
+    <slf4j.version>1.7.36</slf4j.version>
   </properties>
 
   <dependencies>

src/main/java/org/csource/common/IniFileReader.java

@@ -155,13 +155,13 @@ public class IniFileReader {
     } finally {
       try {
         if (in != null) in.close();
-        //System.out.println("loadFrom...finally...in.close(); done");
       } catch (Exception ex) {
         ex.printStackTrace();
       }
     }
   }
 
+  @SuppressWarnings("unchecked")
   private void readToParamTable(InputStream in) throws IOException {
     this.paramTable = new Hashtable();
     if (in == null) return;
@@ -206,7 +206,6 @@ public class IniFileReader {
       try {
         if (bufferedReader != null) bufferedReader.close();
         if (inReader != null) inReader.close();
-        //System.out.println("readToParamTable...finally...bufferedReader.close();inReader.close(); done");
       } catch (Exception ex) {
         ex.printStackTrace();
       }

src/main/java/org/csource/common/MyException.java

@@ -16,6 +16,7 @@ package org.csource.common;
  */
 public class MyException extends Exception {
   public MyException(String s, Exception e) {
+    super(s, e);
   }
 
   public MyException(String message) {

src/main/java/org/csource/fastdfs/ClientGlobal.java

@@ -48,7 +48,6 @@ public class ClientGlobal {
   public static final String PROP_KEY_CONNECTION_POOL_MAX_IDLE_TIME = "fastdfs.connection_pool.max_idle_time";
   public static final String PROP_KEY_CONNECTION_POOL_MAX_WAIT_TIME_IN_MS = "fastdfs.connection_pool.max_wait_time_in_ms";
 
-
   public static final int DEFAULT_CONNECT_TIMEOUT = 5; //second
   public static final int DEFAULT_NETWORK_TIMEOUT = 30; //second
   public static final String DEFAULT_CHARSET = "UTF-8";
@@ -180,7 +179,6 @@ public class ClientGlobal {
     String poolMaxCountPerEntry = props.getProperty(PROP_KEY_CONNECTION_POOL_MAX_COUNT_PER_ENTRY);
     String poolMaxIdleTime  = props.getProperty(PROP_KEY_CONNECTION_POOL_MAX_IDLE_TIME);
     String poolMaxWaitTimeInMS = props.getProperty(PROP_KEY_CONNECTION_POOL_MAX_WAIT_TIME_IN_MS);
-
     if (connectTimeoutInSecondsConf != null && connectTimeoutInSecondsConf.trim().length() != 0) {
       g_connect_timeout = Integer.parseInt(connectTimeoutInSecondsConf.trim()) * 1000;
     }
@@ -221,7 +219,7 @@ public class ClientGlobal {
    *                       server之间用逗号','分隔
    */
   public static void initByTrackers(String trackerServers) throws IOException, MyException {
-    List<InetSocketAddress> list = new ArrayList();
+    List<InetSocketAddress> list = new ArrayList<InetSocketAddress>();
     String spr1 = ",";
     String spr2 = ":";
     String[] arr1 = trackerServers.trim().split(spr1);

src/main/java/org/csource/fastdfs/ProtoStructDecoder.java

@@ -27,6 +27,7 @@ public class ProtoStructDecoder<T extends StructBase> {
   /**
    * decode byte buffer
    */
+  @SuppressWarnings("unchecked")
   public T[] decode(byte[] bs, Class<T> clazz, int fieldsTotalSize) throws Exception {
     if (bs.length % fieldsTotalSize != 0) {
       throw new IOException("byte array length: " + bs.length + " is invalid!");

src/main/java/org/csource/fastdfs/StorageClient.java

@@ -73,11 +73,14 @@ public class StorageClient {
      * upload file to storage server (by file name)
      *
      * @param local_filename local filename to upload
-     * @param file_ext_name  file ext name, do not include dot(.), null to extract ext name from the local filename
+     * @param file_ext_name  file ext name, do not include dot(.), null to extract
+     *                       ext name from the local filename
      * @param meta_list      meta info array
      * @return 2 elements string array if success:<br>
-     * <ul><li>results[0]: the group name to store the file </li></ul>
-     * <ul><li>results[1]: the new created filename</li></ul>
+     *         <ul>
+     *         <li>results[0]: the group name to store the file</li>
+     *         <li>results[1]: the new created filename</li>
+     *         </ul>
      *         return null if fail
      */
     public String[] upload_file(String local_filename, String file_ext_name,
@@ -91,11 +94,14 @@ public class StorageClient {
      *
      * @param group_name     the group name to upload file to, can be empty
      * @param local_filename local filename to upload
-     * @param file_ext_name  file ext name, do not include dot(.), null to extract ext name from the local filename
+     * @param file_ext_name  file ext name, do not include dot(.), null to extract
+     *                       ext name from the local filename
      * @param meta_list      meta info array
      * @return 2 elements string array if success:<br>
-     * <ul><li>results[0]: the group name to store the file </li></ul>
-     * <ul><li>results[1]: the new created filename</li></ul>
+     *         <ul>
+     *         <li>results[0]: the group name to store the file</li>
+     *         <li>results[1]: the new created filename</li>
+     *         </ul>
      *         return null if fail
      */
     protected String[] upload_file(String group_name, String local_filename, String file_ext_name,
@@ -110,11 +116,14 @@ public class StorageClient {
      * @param cmd            the command
      * @param group_name     the group name to upload file to, can be empty
      * @param local_filename local filename to upload
-     * @param file_ext_name  file ext name, do not include dot(.), null to extract ext name from the local filename
+     * @param file_ext_name  file ext name, do not include dot(.), null to extract
+     *                       ext name from the local filename
      * @param meta_list      meta info array
      * @return 2 elements string array if success:<br>
-     * <ul><li>results[0]: the group name to store the file </li></ul>
-     * <ul><li>results[1]: the new created filename</li></ul>
+     *         <ul>
+     *         <li>results[0]: the group name to store the file</li>
+     *         <li>results[1]: the new created filename</li>
+     *         </ul>
      *         return null if fail
      */
     protected String[] upload_file(byte cmd, String group_name, String local_filename, String file_ext_name,
@@ -146,8 +155,10 @@ public class StorageClient {
      * @param file_ext_name file ext name, do not include dot(.)
      * @param meta_list     meta info array
      * @return 2 elements string array if success:<br>
-     * <ul><li>results[0]: the group name to store the file</li></ul>
-     * <ul><li>results[1]: the new created filename</li></ul>
+     *         <ul>
+     *         <li>results[0]: the group name to store the file</li>
+     *         <li>results[1]: the new created filename</li>
+     *         </ul>
      *         return null if fail
      */
     public String[] upload_file(byte[] file_buff, int offset, int length, String file_ext_name,
@@ -166,8 +177,10 @@ public class StorageClient {
      * @param file_ext_name file ext name, do not include dot(.)
      * @param meta_list     meta info array
      * @return 2 elements string array if success:<br>
-     * <ul><li>results[0]: the group name to store the file</li></ul>
-     * <ul><li>results[1]: the new created filename</li></ul>
+     *         <ul>
+     *         <li>results[0]: the group name to store the file</li>
+     *         <li>results[1]: the new created filename</li>
+     *         </ul>
      *         return null if fail
      */
     public String[] upload_file(String group_name, byte[] file_buff, int offset, int length,
@@ -183,8 +196,10 @@ public class StorageClient {
      * @param file_ext_name file ext name, do not include dot(.)
      * @param meta_list     meta info array
      * @return 2 elements string array if success:<br>
-     * <ul><li>results[0]: the group name to store the file</li></ul>
-     * <ul><li>results[1]: the new created filename</li></ul>
+     *         <ul>
+     *         <li>results[0]: the group name to store the file</li>
+     *         <li>results[1]: the new created filename</li>
+     *         </ul>
      *         return null if fail
      */
     public String[] upload_file(byte[] file_buff, String file_ext_name,
@@ -201,8 +216,10 @@ public class StorageClient {
      * @param file_ext_name file ext name, do not include dot(.)
      * @param meta_list     meta info array
      * @return 2 elements string array if success:<br>
-     * <ul><li>results[0]: the group name to store the file</li></ul>
-     * <ul><li>results[1]: the new created filename</li></ul>
+     *         <ul>
+     *         <li>results[0]: the group name to store the file</li>
+     *         <li>results[1]: the new created filename</li>
+     *         </ul>
      *         return null if fail
      */
     public String[] upload_file(String group_name, byte[] file_buff,
@@ -220,8 +237,10 @@ public class StorageClient {
      * @param file_ext_name file ext name, do not include dot(.)
      * @param meta_list     meta info array
      * @return 2 elements string array if success:<br>
-     * <ul><li>results[0]: the group name to store the file</li></ul>
-     * <ul><li>results[1]: the new created filename</li></ul>
+     *         <ul>
+     *         <li>results[0]: the group name to store the file</li>
+     *         <li>results[1]: the new created filename</li>
+     *         </ul>
      *         return null if fail
      */
     public String[] upload_file(String group_name, long file_size, UploadCallback callback,
@@ -240,11 +259,14 @@ public class StorageClient {
      * @param master_filename the master file name to generate the slave file
      * @param prefix_name     the prefix name to generate the slave file
      * @param local_filename  local filename to upload
-     * @param file_ext_name   file ext name, do not include dot(.), null to extract ext name from the local filename
+     * @param file_ext_name   file ext name, do not include dot(.), null to extract
+     *                        ext name from the local filename
      * @param meta_list       meta info array
      * @return 2 elements string array if success:<br>
-     * <ul><li>results[0]: the group name to store the file </li></ul>
-     * <ul><li>results[1]: the new created filename</li></ul>
+     *         <ul>
+     *         <li>results[0]: the group name to store the file</li>
+     *         <li>results[1]: the new created filename</li>
+     *         </ul>
      *         return null if fail
      */
     public String[] upload_file(String group_name, String master_filename, String prefix_name,
@@ -266,8 +288,8 @@ public class StorageClient {
         }
 
         try {
-            return this.do_upload_file(ProtoCommon.STORAGE_PROTO_CMD_UPLOAD_SLAVE_FILE, group_name, master_filename, prefix_name,
-                    file_ext_name, f.length(), new UploadStream(fis, f.length()), meta_list);
+            return this.do_upload_file(ProtoCommon.STORAGE_PROTO_CMD_UPLOAD_SLAVE_FILE, group_name, master_filename,
+                    prefix_name, file_ext_name, f.length(), new UploadStream(fis, f.length()), meta_list);
         } finally {
             fis.close();
         }
@@ -283,8 +305,10 @@ public class StorageClient {
      * @param file_ext_name   file ext name, do not include dot(.)
      * @param meta_list       meta info array
      * @return 2 elements string array if success:<br>
-     * <ul><li>results[0]: the group name to store the file</li></ul>
-     * <ul><li>results[1]: the new created filename</li></ul>
+     *         <ul>
+     *         <li>results[0]: the group name to store the file</li>
+     *         <li>results[1]: the new created filename</li>
+     *         </ul>
      *         return null if fail
      */
     public String[] upload_file(String group_name, String master_filename, String prefix_name,
@@ -295,8 +319,9 @@ public class StorageClient {
             throw new MyException("invalid arguement");
         }
 
-        return this.do_upload_file(ProtoCommon.STORAGE_PROTO_CMD_UPLOAD_SLAVE_FILE, group_name, master_filename, prefix_name,
-                file_ext_name, file_buff.length, new UploadBuff(file_buff, 0, file_buff.length), meta_list);
+        return this.do_upload_file(ProtoCommon.STORAGE_PROTO_CMD_UPLOAD_SLAVE_FILE, group_name, master_filename,
+                prefix_name, file_ext_name, file_buff.length, new UploadBuff(file_buff, 0, file_buff.length),
+                meta_list);
     }
 
     /**
@@ -311,8 +336,10 @@ public class StorageClient {
      * @param file_ext_name   file ext name, do not include dot(.)
      * @param meta_list       meta info array
      * @return 2 elements string array if success:<br>
-     * <ul><li>results[0]: the group name to store the file</li></ul>
-     * <ul><li>results[1]: the new created filename</li></ul>
+     *         <ul>
+     *         <li>results[0]: the group name to store the file</li>
+     *         <li>results[1]: the new created filename</li>
+     *         </ul>
      *         return null if fail
      */
     public String[] upload_file(String group_name, String master_filename, String prefix_name,
@@ -324,8 +351,8 @@ public class StorageClient {
             throw new MyException("invalid arguement");
         }
 
-        return this.do_upload_file(ProtoCommon.STORAGE_PROTO_CMD_UPLOAD_SLAVE_FILE, group_name, master_filename, prefix_name,
-                file_ext_name, length, new UploadBuff(file_buff, offset, length), meta_list);
+        return this.do_upload_file(ProtoCommon.STORAGE_PROTO_CMD_UPLOAD_SLAVE_FILE, group_name, master_filename,
+                prefix_name, file_ext_name, length, new UploadBuff(file_buff, offset, length), meta_list);
     }
 
     /**
@@ -339,26 +366,31 @@ public class StorageClient {
      * @param file_ext_name   file ext name, do not include dot(.)
      * @param meta_list       meta info array
      * @return 2 elements string array if success:<br>
-     * <ul><li>results[0]: the group name to store the file</li></ul>
-     * <ul><li>results[1]: the new created filename</li></ul>
+     *         <ul>
+     *         <li>results[0]: the group name to store the file</li>
+     *         <li>results[1]: the new created filename</li>
+     *         </ul>
      *         return null if fail
      */
     public String[] upload_file(String group_name, String master_filename,
             String prefix_name, long file_size, UploadCallback callback,
             String file_ext_name, NameValuePair[] meta_list) throws IOException, MyException {
-        return this.do_upload_file(ProtoCommon.STORAGE_PROTO_CMD_UPLOAD_SLAVE_FILE, group_name, master_filename, prefix_name,
-                file_ext_name, file_size, callback, meta_list);
+        return this.do_upload_file(ProtoCommon.STORAGE_PROTO_CMD_UPLOAD_SLAVE_FILE, group_name, master_filename,
+                prefix_name, file_ext_name, file_size, callback, meta_list);
     }
 
     /**
      * upload appender file to storage server (by file name)
      *
      * @param local_filename local filename to upload
-     * @param file_ext_name  file ext name, do not include dot(.), null to extract ext name from the local filename
+     * @param file_ext_name  file ext name, do not include dot(.), null to extract
+     *                       ext name from the local filename
      * @param meta_list      meta info array
      * @return 2 elements string array if success:<br>
-     * <ul><li>results[0]: the group name to store the file </li></ul>
-     * <ul><li>results[1]: the new created filename</li></ul>
+     *         <ul>
+     *         <li>results[0]: the group name to store the file</li>
+     *         <li>results[1]: the new created filename</li>
+     *         </ul>
      *         return null if fail
      */
     public String[] upload_appender_file(String local_filename, String file_ext_name,
@@ -372,11 +404,14 @@ public class StorageClient {
      *
      * @param group_name     the group name to upload file to, can be empty
      * @param local_filename local filename to upload
-     * @param file_ext_name  file ext name, do not include dot(.), null to extract ext name from the local filename
+     * @param file_ext_name  file ext name, do not include dot(.), null to extract
+     *                       ext name from the local filename
      * @param meta_list      meta info array
      * @return 2 elements string array if success:<br>
-     * <ul><li>results[0]: the group name to store the file </li></ul>
-     * <ul><li>results[1]: the new created filename</li></ul>
+     *         <ul>
+     *         <li>results[0]: the group name to store the file</li>
+     *         <li>results[1]: the new created filename</li>
+     *         </ul>
      *         return null if fail
      */
     protected String[] upload_appender_file(String group_name, String local_filename, String file_ext_name,
@@ -394,8 +429,10 @@ public class StorageClient {
      * @param file_ext_name file ext name, do not include dot(.)
      * @param meta_list     meta info array
      * @return 2 elements string array if success:<br>
-     * <ul><li>results[0]: the group name to store the file</li></ul>
-     * <ul><li>results[1]: the new created filename</li></ul>
+     *         <ul>
+     *         <li>results[0]: the group name to store the file</li>
+     *         <li>results[1]: the new created filename</li>
+     *         </ul>
      *         return null if fail
      */
     public String[] upload_appender_file(byte[] file_buff, int offset, int length, String file_ext_name,
@@ -414,14 +451,16 @@ public class StorageClient {
      * @param file_ext_name file ext name, do not include dot(.)
      * @param meta_list     meta info array
      * @return 2 elements string array if success:<br>
-     * <ul><li>results[0]: the group name to store the file</li></ul>
-     * <ul><li>results[1]: the new created filename</li></ul>
+     *         <ul>
+     *         <li>results[0]: the group name to store the file</li>
+     *         <li>results[1]: the new created filename</li>
+     *         </ul>
      *         return null if fail
      */
     public String[] upload_appender_file(String group_name, byte[] file_buff, int offset, int length,
             String file_ext_name, NameValuePair[] meta_list) throws IOException, MyException {
-        return this.do_upload_file(ProtoCommon.STORAGE_PROTO_CMD_UPLOAD_APPENDER_FILE, group_name, null, null, file_ext_name,
-                length, new UploadBuff(file_buff, offset, length), meta_list);
+        return this.do_upload_file(ProtoCommon.STORAGE_PROTO_CMD_UPLOAD_APPENDER_FILE, group_name, null, null,
+                file_ext_name, length, new UploadBuff(file_buff, offset, length), meta_list);
     }
 
     /**
@@ -431,8 +470,10 @@ public class StorageClient {
      * @param file_ext_name file ext name, do not include dot(.)
      * @param meta_list     meta info array
      * @return 2 elements string array if success:<br>
-     * <ul><li>results[0]: the group name to store the file</li></ul>
-     * <ul><li>results[1]: the new created filename</li></ul>
+     *         <ul>
+     *         <li>results[0]: the group name to store the file</li>
+     *         <li>results[1]: the new created filename</li>
+     *         </ul>
      *         return null if fail
      */
     public String[] upload_appender_file(byte[] file_buff, String file_ext_name,
@@ -449,14 +490,16 @@ public class StorageClient {
      * @param file_ext_name file ext name, do not include dot(.)
      * @param meta_list     meta info array
      * @return 2 elements string array if success:<br>
-     * <ul><li>results[0]: the group name to store the file</li></ul>
-     * <ul><li>results[1]: the new created filename</li></ul>
+     *         <ul>
+     *         <li>results[0]: the group name to store the file</li>
+     *         <li>results[1]: the new created filename</li>
+     *         </ul>
      *         return null if fail
      */
     public String[] upload_appender_file(String group_name, byte[] file_buff,
             String file_ext_name, NameValuePair[] meta_list) throws IOException, MyException {
-        return this.do_upload_file(ProtoCommon.STORAGE_PROTO_CMD_UPLOAD_APPENDER_FILE, group_name, null, null, file_ext_name,
-                file_buff.length, new UploadBuff(file_buff, 0, file_buff.length), meta_list);
+        return this.do_upload_file(ProtoCommon.STORAGE_PROTO_CMD_UPLOAD_APPENDER_FILE, group_name, null, null,
+                file_ext_name, file_buff.length, new UploadBuff(file_buff, 0, file_buff.length), meta_list);
     }
 
     /**
@@ -468,8 +511,10 @@ public class StorageClient {
      * @param file_ext_name file ext name, do not include dot(.)
      * @param meta_list     meta info array
      * @return 2 elements string array if success:<br>
-     * <ul><li>results[0]: the group name to store the file</li></ul>
-     * <ul><li>results[1]: the new created filename</li></ul>
+     *         <ul>
+     *         <li>results[0]: the group name to store the file</li>
+     *         <li>results[1]: the new created filename</li>
+     *         </ul>
      *         return null if fail
      */
     public String[] upload_appender_file(String group_name, long file_size, UploadCallback callback,
@@ -477,7 +522,8 @@ public class StorageClient {
         final String master_filename = null;
         final String prefix_name = null;
 
-        return this.do_upload_file(ProtoCommon.STORAGE_PROTO_CMD_UPLOAD_APPENDER_FILE, group_name, master_filename, prefix_name,
+        return this.do_upload_file(ProtoCommon.STORAGE_PROTO_CMD_UPLOAD_APPENDER_FILE, group_name, master_filename,
+                prefix_name,
                 file_ext_name, file_size, callback, meta_list);
     }
 
@@ -489,7 +535,8 @@ public class StorageClient {
      * @param local_filename    local filename to append
      * @return 0 for success, != 0 for error (error no)
      */
-    public int append_file(String group_name, String appender_filename, String local_filename) throws IOException, MyException {
+    public int append_file(String group_name, String appender_filename, String local_filename)
+            throws IOException, MyException {
         File f = new File(local_filename);
         FileInputStream fis = new FileInputStream(f);
 
@@ -508,8 +555,10 @@ public class StorageClient {
      * @param file_buff         file content/buff
      * @return 0 for success, != 0 for error (error no)
      */
-    public int append_file(String group_name, String appender_filename, byte[] file_buff) throws IOException, MyException {
-        return this.do_append_file(group_name, appender_filename, file_buff.length, new UploadBuff(file_buff, 0, file_buff.length));
+    public int append_file(String group_name, String appender_filename, byte[] file_buff)
+            throws IOException, MyException {
+        return this.do_append_file(group_name, appender_filename, file_buff.length,
+                new UploadBuff(file_buff, 0, file_buff.length));
     }
 
     /**
@@ -617,11 +666,14 @@ public class StorageClient {
      * @param group_name        the group name of appender file
      * @param appender_filename the appender filename
      * @return 2 elements string array if success:<br>
-     * <ul><li> results[0]: the group name to store the file</li></ul>
-     * <ul><li> results[1]: the new created filename</li></ul>
+     *         <ul>
+     *         <li>results[0]: the group name to store the file</li>
+     *         <li>results[1]: the new created filename</li>
+     *         </ul>
      *         return null if fail
      */
-    public String[] regenerate_appender_filename(String group_name, String appender_filename) throws IOException, MyException {
+    public String[] regenerate_appender_filename(String group_name, String appender_filename)
+            throws IOException, MyException {
         byte[] header;
         boolean bNewStorageServer;
         Connection connection = null;
@@ -700,8 +752,10 @@ public class StorageClient {
      * @param callback        the write data callback object
      * @param meta_list       meta info array
      * @return 2 elements string array if success:<br>
-     * <ul><li> results[0]: the group name to store the file</li></ul>
-     * <ul><li> results[1]: the new created filename</li></ul>
+     *         <ul>
+     *         <li>results[0]: the group name to store the file</li>
+     *         <li>results[1]: the new created filename</li>
+     *         </ul>
      *         return null if fail
      */
     protected String[] do_upload_file(byte cmd, String group_name, String master_filename,
@@ -731,7 +785,6 @@ public class StorageClient {
 
         try {
             connection = this.storageServer.getConnection();
-
             ext_name_bs = new byte[ProtoCommon.FDFS_FILE_EXT_NAME_MAX_LEN];
             Arrays.fill(ext_name_bs, (byte) 0);
             if (file_ext_name != null && file_ext_name.length() > 0) {
@@ -747,8 +800,8 @@ public class StorageClient {
                 masterFilenameBytes = master_filename.getBytes(ClientGlobal.g_charset);
 
                 sizeBytes = new byte[2 * ProtoCommon.FDFS_PROTO_PKG_LEN_SIZE];
-                body_len = sizeBytes.length + ProtoCommon.FDFS_FILE_PREFIX_MAX_LEN + ProtoCommon.FDFS_FILE_EXT_NAME_MAX_LEN
-                        + masterFilenameBytes.length + file_size;
+                body_len = sizeBytes.length + ProtoCommon.FDFS_FILE_PREFIX_MAX_LEN
+                        + ProtoCommon.FDFS_FILE_EXT_NAME_MAX_LEN + masterFilenameBytes.length + file_size;
 
                 hexLenBytes = ProtoCommon.long2buff(master_filename.length());
                 System.arraycopy(hexLenBytes, 0, sizeBytes, 0, hexLenBytes.length);
@@ -1164,7 +1217,8 @@ public class StorageClient {
      * @param download_bytes  download bytes, 0 for remain bytes from offset
      * @return file content/buff, return null if fail
      */
-    public byte[] download_file(String group_name, String remote_filename, long file_offset, long download_bytes) throws IOException, MyException {
+    public byte[] download_file(String group_name, String remote_filename, long file_offset, long download_bytes)
+            throws IOException, MyException {
         boolean bNewStorageServer = this.newReadableStorageConnection(group_name, remote_filename);
         Connection connection = this.storageServer.getConnection();
 
@@ -1244,17 +1298,18 @@ public class StorageClient {
                 long remainBytes = header.body_len;
                 int bytes;
 
-                //System.out.println("expect_body_len=" + header.body_len);
+                // System.out.println("expect_body_len=" + header.body_len);
 
                 while (remainBytes > 0) {
                     if ((bytes = in.read(buff, 0, remainBytes > buff.length ? buff.length : (int) remainBytes)) < 0) {
-                        throw new IOException("recv package size " + (header.body_len - remainBytes) + " != " + header.body_len);
+                        throw new IOException(
+                                "recv package size " + (header.body_len - remainBytes) + " != " + header.body_len);
                     }
 
                     out.write(buff, 0, bytes);
                     remainBytes -= bytes;
 
-                    //System.out.println("totalBytes=" + (header.body_len - remainBytes));
+                    // System.out.println("totalBytes=" + (header.body_len - remainBytes));
                 }
 
                 return 0;
@@ -1332,7 +1387,7 @@ public class StorageClient {
             long remainBytes = header.body_len;
             int bytes;
 
-            //System.out.println("expect_body_len=" + header.body_len);
+            // System.out.println("expect_body_len=" + header.body_len);
 
             while (remainBytes > 0) {
                 if ((bytes = in.read(buff, 0, remainBytes > buff.length ? buff.length : (int) remainBytes)) < 0) {
@@ -1345,7 +1400,7 @@ public class StorageClient {
                 }
 
                 remainBytes -= bytes;
-                //System.out.println("totalBytes=" + (header.body_len - remainBytes));
+                // System.out.println("totalBytes=" + (header.body_len - remainBytes));
             }
 
             return 0;
@@ -1407,10 +1462,14 @@ public class StorageClient {
      * @param remote_filename filename on storage server
      * @param meta_list       meta item array
      * @param op_flag         flag, can be one of following values: <br>
-     *                        <ul><li> ProtoCommon.STORAGE_SET_METADATA_FLAG_OVERWRITE: overwrite all old
-     *                        metadata items</li></ul>
-     *                        <ul><li> ProtoCommon.STORAGE_SET_METADATA_FLAG_MERGE: merge, insert when
-     *                        the metadata item not exist, otherwise update it</li></ul>
+     *                        <ul>
+     *                        <li>ProtoCommon.STORAGE_SET_METADATA_FLAG_OVERWRITE:
+     *                        overwrite all old
+     *                        metadata items</li>
+     *                        <li>ProtoCommon.STORAGE_SET_METADATA_FLAG_MERGE:
+     *                        merge, insert when
+     *                        the metadata item not exist, otherwise update it</li>
+     *                        </ul>
      * @return 0 for success, !=0 fail (error code)
      */
     public int set_metadata(String group_name, String remote_filename,
@@ -1517,7 +1576,7 @@ public class StorageClient {
         }
 
         if (file_type == FileInfo.FILE_TYPE_SLAVE ||
-                file_type == FileInfo.FILE_TYPE_APPENDER) { //slave file or appender file
+                file_type == FileInfo.FILE_TYPE_APPENDER) { // slave file or appender file
             FileInfo fi = this.query_file_info(group_name, remote_filename);
             if (fi == null) {
                 return null;
@@ -1529,7 +1588,7 @@ public class StorageClient {
 
         int create_timestamp = ProtoCommon.buff2int(buff, 4);
         if ((file_size >> 63) != 0) {
-            file_size &= 0xFFFFFFFFL;  //low 32 bits is file size
+            file_size &= 0xFFFFFFFFL; // low 32 bits is file size
         }
         int crc32 = ProtoCommon.buff2int(buff, 4 * 4);
 
@@ -1619,7 +1678,7 @@ public class StorageClient {
             TrackerClient tracker = new TrackerClient();
             this.storageServer = tracker.getStoreStorage(this.trackerServer, group_name);
             if (this.storageServer == null) {
-                throw new MyException("getStoreStorage fail, errno code: " + tracker.getErrorCode());
+                throw new MyException("getStoreStorage fail, error code: " + tracker.getErrorCode());
             }
             return true;
         }
@@ -1632,7 +1691,8 @@ public class StorageClient {
      * @param remote_filename filename on storage server
      * @return true if create a new connection
      */
-    protected boolean newReadableStorageConnection(String group_name, String remote_filename) throws IOException, MyException {
+    protected boolean newReadableStorageConnection(String group_name, String remote_filename)
+            throws IOException, MyException {
         if (this.storageServer != null) {
             return false;
         } else {
@@ -1652,7 +1712,8 @@ public class StorageClient {
      * @param remote_filename filename on storage server
      * @return true if create a new connection
      */
-    protected boolean newUpdatableStorageConnection(String group_name, String remote_filename) throws IOException, MyException {
+    protected boolean newUpdatableStorageConnection(String group_name, String remote_filename)
+            throws IOException, MyException {
         if (this.storageServer != null) {
             return false;
         } else {
@@ -1672,7 +1733,8 @@ public class StorageClient {
      * @param group_name      the group name of storage server
      * @param remote_filename filename on storage server
      */
-    protected void send_package(byte cmd, String group_name, String remote_filename, Connection connection) throws IOException {
+    protected void send_package(byte cmd, String group_name, String remote_filename, Connection connection)
+            throws IOException {
         byte[] header;
         byte[] groupBytes;
         byte[] filenameBytes;
@@ -1793,7 +1855,8 @@ public class StorageClient {
         }
 
         /**
-         * send file content callback function, be called only once when the file uploaded
+         * send file content callback function, be called only once when the file
+         * uploaded
          *
          * @param out output stream for writing file content
          * @return 0 success, return none zero(errno) if fail

src/main/java/org/csource/fastdfs/TrackerClient.java

@@ -71,6 +71,71 @@ public class TrackerClient {
         return this.getStoreStorage(trackerServer, groupName);
     }
 
+    public Connection getConnection(TrackerServer trackerServer) throws IOException, MyException {
+        Connection connection = null;
+        int length = this.tracker_group.tracker_servers.length;
+        boolean failOver = length > 1 && trackerServer == null;
+        try {
+            if (trackerServer == null) {
+                trackerServer = getTrackerServer();
+                if (trackerServer == null) {
+                    throw new MyException("tracker server is empty!");
+                }
+            }
+            connection = trackerServer.getConnection();
+        } catch (IOException e) {
+            if (failOver) {
+                System.err.println("trackerServer get connection error, emsg:" + e.getMessage());
+            } else {
+                throw e;
+            }
+        } catch (MyException e) {
+            if (failOver) {
+                System.err.println("trackerServer get connection error, emsg:" + e.getMessage());
+            } else {
+                throw e;
+            }
+        }
+        if (connection != null || !failOver) {
+            return connection;
+        }
+        //do fail over
+        int currentIndex = 0;
+        if (trackerServer != null) {
+            currentIndex = trackerServer.getIndex();
+        }
+        int failOverCount = 0;
+        while (failOverCount < length - 1) {
+            failOverCount++;
+            currentIndex++;
+            if (currentIndex >= length) {
+                currentIndex = 0;
+            }
+            try {
+                trackerServer = this.tracker_group.getTrackerServer(currentIndex);
+                if (trackerServer == null) {
+                    throw new MyException("tracker server is empty!");
+                }
+                return trackerServer.getConnection();
+            } catch (IOException e) {
+                System.err.println("fail over trackerServer get connection error, failOverCount:" + failOverCount + "," + e.getMessage());
+                if (failOverCount == length - 1) {
+                    throw e;
+                }
+
+            } catch (MyException e) {
+                System.err.println("fail over trackerServer get connection error, failOverCount:" + failOverCount + ", " + e.getMessage());
+                if (failOverCount == length - 1) {
+                    throw e;
+                }
+            }
+
+
+        }
+        return null;
+    }
+
+
     /**
      * query storage server to upload file
      *
@@ -85,12 +150,7 @@ public class TrackerClient {
         byte cmd;
         int out_len;
         byte store_path;
-        Connection connection;
-
-        if (trackerServer == null) {
-            trackerServer = getTrackerServer();
-        }
-        connection = trackerServer.getConnection();
+        Connection connection = getConnection(trackerServer);
         OutputStream out = connection.getOutputStream();
 
         try {
@@ -170,16 +230,7 @@ public class TrackerClient {
         int port;
         byte cmd;
         int out_len;
-        Connection connection;
-
-        if (trackerServer == null) {
-            trackerServer = getTrackerServer();
-            if (trackerServer == null) {
-                return null;
-            }
-        }
-
-        connection = trackerServer.getConnection();
+        Connection connection = getConnection(trackerServer);
         OutputStream out = connection.getOutputStream();
 
         try {
@@ -343,15 +394,7 @@ public class TrackerClient {
         int len;
         String ip_addr;
         int port;
-        Connection connection;
-
-        if (trackerServer == null) {
-            trackerServer = getTrackerServer();
-            if (trackerServer == null) {
-                return null;
-            }
-        }
-        connection = trackerServer.getConnection();
+        Connection connection = getConnection(trackerServer);
         OutputStream out = connection.getOutputStream();
 
         try {
@@ -473,16 +516,7 @@ public class TrackerClient {
         byte cmd;
         int out_len;
         byte store_path;
-        Connection connection;
-
-        if (trackerServer == null) {
-            trackerServer = getTrackerServer();
-            if (trackerServer == null) {
-                return null;
-            }
-        }
-
-        connection = trackerServer.getConnection();
+        Connection connection = getConnection(trackerServer);
         OutputStream out = connection.getOutputStream();
 
         try {
@@ -548,15 +582,7 @@ public class TrackerClient {
         byte[] bGroupName;
         byte[] bs;
         int len;
-        Connection connection;
-
-        if (trackerServer == null) {
-            trackerServer = getTrackerServer();
-            if (trackerServer == null) {
-                return null;
-            }
-        }
-        connection = trackerServer.getConnection();
+        Connection connection = getConnection(trackerServer);
         OutputStream out = connection.getOutputStream();
 
         try {

src/main/java/org/csource/fastdfs/TrackerGroup.java

@@ -39,9 +39,8 @@ public class TrackerGroup {
      * @return connected tracker server, null for fail
      */
     public TrackerServer getTrackerServer(int serverIndex) throws IOException {
-    return new TrackerServer(this.tracker_servers[serverIndex]);
+        return new TrackerServer(this.tracker_servers[serverIndex], serverIndex);
     }
-
     /**
      * return connected tracker server
      *

src/main/java/org/csource/fastdfs/TrackerServer.java

@@ -25,11 +25,18 @@ import java.net.InetSocketAddress;
 public class TrackerServer {
     protected InetSocketAddress inetSockAddr;
 
+    protected int index;
+
 
     public TrackerServer(InetSocketAddress inetSockAddr) throws IOException {
         this.inetSockAddr = inetSockAddr;
     }
 
+    public TrackerServer(InetSocketAddress inetSockAddr, int index) {
+        this.inetSockAddr = inetSockAddr;
+        this.index = index;
+    }
+
     public Connection getConnection() throws MyException, IOException {
         Connection connection;
         if (ClientGlobal.g_connection_pool_enabled) {
@@ -48,4 +55,11 @@ public class TrackerServer {
         return this.inetSockAddr;
     }
 
+    public int getIndex() {
+        return index;
+    }
+
+    public void setIndex(int index) {
+        this.index = index;
+    }
 }

src/test/java/org/csource/fastdfs/FdfsTest.java

@@ -87,9 +87,9 @@ public class FdfsTest {
 
     @Test
     public void download() throws Exception {
-        String[] uploadresult = {"group1", "M00/00/00/wKgBZV0phl2ASV1nAACk1tFxwrM3814331"};
+        String[] uploadresult = {"group1", "M00/00/00/J2fL12PVypeAWiGcAAM_gDeWVyw5817085"};
         byte[] result = storageClient.download_file(uploadresult[0], uploadresult[1]);
-        String local_filename = "build.PNG";
+        String local_filename = "commitment.d2f57e10.jpg";
         writeByteToFile(result, local_filename);
         File file = new File(local_filename);
         Assert.assertTrue(file.isFile());
@@ -98,17 +98,17 @@ public class FdfsTest {
     @Test
     public void testUploadDownload() throws Exception {
         NameValuePair[] metaList = new NameValuePair[1];
-        String local_filename = "build.PNG";
+        String local_filename = "commitment.d2f57e10 (2).jpg";
         metaList[0] = new NameValuePair("fileName", local_filename);
-        File file = new File("C:/Users/chengdu/Desktop/build.PNG");
+        File file = new File("/Users/iyw/Downloads/commitment.d2f57e10 (2).jpg");
         InputStream inputStream = new FileInputStream(file);
         int length = inputStream.available();
         byte[] bytes = new byte[length];
         inputStream.read(bytes);
         String[] result = storageClient.upload_file(bytes, null, metaList);
-        Assert.assertTrue(storageClient.isConnected());
+        //Assert.assertTrue(storageClient.isConnected());
         // pool testOnborrow  isAvaliable
-        Assert.assertTrue(storageClient.isAvaliable());
+       // Assert.assertTrue(storageClient.isAvaliable());
         LOGGER.info("result {}", Arrays.asList(result));
         byte[] resultbytes = storageClient.download_file(result[0], result[1]);
         writeByteToFile(resultbytes, local_filename);