fix code

hutool-core/src/main/java/cn/hutool/core/map/MapUtil.java

@@ -12,6 +12,7 @@
 
 package cn.hutool.core.map;
 
+import cn.hutool.core.array.ArrayUtil;
 import cn.hutool.core.collection.CollUtil;
 import cn.hutool.core.collection.ListUtil;
 import cn.hutool.core.collection.iter.ArrayIter;
@@ -19,23 +20,11 @@ import cn.hutool.core.collection.iter.IterUtil;
 import cn.hutool.core.exceptions.UtilException;
 import cn.hutool.core.reflect.ConstructorUtil;
 import cn.hutool.core.text.StrUtil;
-import cn.hutool.core.array.ArrayUtil;
+import cn.hutool.core.util.JdkUtil;
 import cn.hutool.core.util.ObjUtil;
 
-import java.util.AbstractMap;
+import java.util.*;
-import java.util.ArrayList;
-import java.util.Collections;
-import java.util.Comparator;
-import java.util.HashMap;
-import java.util.IdentityHashMap;
-import java.util.Iterator;
-import java.util.LinkedHashMap;
-import java.util.List;
-import java.util.Map;
 import java.util.Map.Entry;
-import java.util.NavigableMap;
-import java.util.SortedMap;
-import java.util.TreeMap;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.function.BiFunction;
 import java.util.function.Function;
@@ -1282,6 +1271,7 @@ public class MapUtil extends MapGetUtil {
 	 * 方法来自Dubbo，解决使用ConcurrentHashMap.computeIfAbsent导致的死循环问题。（issues#2349）<br>
 	 * A temporary workaround for Java 8 specific performance issue JDK-8161372 .<br>
 	 * This class should be removed once we drop Java 8 support.
+	 * 参考：https://github.com/apache/dubbo/blob/3.2/dubbo-common/src/main/java/org/apache/dubbo/common/utils/ConcurrentHashMapUtils.java
 	 *
 	 * @param <K>             键类型
 	 * @param <V>             值类型
@@ -1292,11 +1282,15 @@ public class MapUtil extends MapGetUtil {
 	 * @see <a href="https://bugs.openjdk.java.net/browse/JDK-8161372">https://bugs.openjdk.java.net/browse/JDK-8161372</a>
 	 */
 	public static <K, V> V computeIfAbsent(final Map<K, V> map, final K key, final Function<? super K, ? extends V> mappingFunction) {
-		V value = map.get(key);
+		if (JdkUtil.IS_JDK8) {
-		if (null == value) {
+			V value = map.get(key);
-			map.putIfAbsent(key, mappingFunction.apply(key));
+			if (null == value) {
-			value = map.get(key);
+				//map.putIfAbsent(key, mappingFunction.apply(key));
+				value = map.computeIfAbsent(key, mappingFunction);
+			}
+			return value;
+		} else {
+			return map.computeIfAbsent(key, mappingFunction);
 		}
-		return value;
 	}
 }

hutool-core/src/main/java/cn/hutool/core/util/JdkUtil.java

@@ -57,18 +57,19 @@ public class JdkUtil {
 	 * @return JVM名称
 	 */
 	private static String _getJvmName() {
-		return System.getProperty("java.vm.name");
+		return SystemUtil.getQuietly("java.vm.name");
 	}
 
 	/**
-	 * 根据{@code java.specification.version}属性值，获取版本号
+	 * 根据{@code java.specification.version}属性值，获取版本号<br>
+	 * 默认8
 	 *
 	 * @return 版本号
 	 */
 	private static int _getJvmVersion() {
-		int jvmVersion = -1;
+		int jvmVersion = 8;
 
-		String javaSpecVer = System.getProperty("java.specification.version");
+		String javaSpecVer = SystemUtil.getQuietly("java.specification.version");
 		if (StrUtil.isNotBlank(javaSpecVer)) {
 			if (javaSpecVer.startsWith("1.")) {
 				javaSpecVer = javaSpecVer.substring(2);

hutool-core/src/main/java/cn/hutool/core/util/SystemUtil.java

@@ -30,7 +30,9 @@ import java.util.Properties;
  */
 public class SystemUtil {
 
-	/** Hutool自定义系统属性：是否解析日期字符串采用严格模式 */
+	/**
+	 * Hutool自定义系统属性：是否解析日期字符串采用严格模式
+	 */
 	public static String HUTOOL_DATE_LENIENT = "hutool.date.lenient";
 
 	/**
@@ -43,7 +45,31 @@ public class SystemUtil {
 	 * @see System#getenv(String)
 	 */
 	public static String get(final String name, final String defaultValue) {
-		return ObjUtil.defaultIfNull(get(name, false), defaultValue);
+		return ObjUtil.defaultIfNull(get(name), defaultValue);
+	}
+
+	/**
+	 * 获得System属性
+	 *
+	 * @param key 键
+	 * @return 属性值
+	 * @see System#getProperty(String)
+	 * @see System#getenv(String)
+	 */
+	public static String get(final String key) {
+		return get(key, false);
+	}
+
+	/**
+	 * 获得System属性，忽略无权限问题
+	 *
+	 * @param key 键
+	 * @return 属性值
+	 * @see System#getProperty(String)
+	 * @see System#getenv(String)
+	 */
+	public static String getQuietly(final String key) {
+		return get(key, true);
 	}
 
 	/**
@@ -62,7 +88,7 @@ public class SystemUtil {
 		} catch (final SecurityException e) {
 			if (false == quiet) {
 				Console.error("Caught a SecurityException reading the system property '{}'; " +
-						"the SystemUtil property value will default to null.", name);
+					"the SystemUtil property value will default to null.", name);
 			}
 		}
 
@@ -72,7 +98,7 @@ public class SystemUtil {
 			} catch (final SecurityException e) {
 				if (false == quiet) {
 					Console.error("Caught a SecurityException reading the system env '{}'; " +
-							"the SystemUtil env value will default to null.", name);
+						"the SystemUtil env value will default to null.", name);
 				}
 			}
 		}
@@ -80,18 +106,6 @@ public class SystemUtil {
 		return value;
 	}
 
-	/**
-	 * 获得System属性
-	 *
-	 * @param key 键
-	 * @return 属性值
-	 * @see System#getProperty(String)
-	 * @see System#getenv(String)
-	 */
-	public static String get(final String key) {
-		return get(key, null);
-	}
-
 	/**
 	 * 获得boolean类型值
 	 *