fix ZipUtil

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

@@ -228,6 +228,7 @@ public class ZipUtil {
 				// 调用递归压缩方法进行目录或文件压缩
 				zip(srcFile, srcRootDir, zipOutputStream, filter);
 				zipOutputStream.flush();
+				zipOutputStream.finish();
 			}
 		} catch (IOException e) {
 			throw new IORuntimeException(e);

hutool-core/src/test/java/cn/hutool/core/util/ZipUtilTest.java

@@ -7,6 +7,9 @@ import org.junit.Ignore;
 import org.junit.Test;
 
 import java.io.File;
+import java.io.FileOutputStream;
+import java.io.OutputStream;
+import java.nio.charset.Charset;
 
 /**
  * {@link ZipUtil}单元测试
@@ -89,4 +92,18 @@ public class ZipUtilTest {
 		//保证正常还原
 		Assert.assertEquals(data, StrUtil.utf8Str(unGzip2));
 	}
+
+	@Test
+	@Ignore
+	public void zipStreamTest(){
+		//https://github.com/looly/hutool/issues/944
+		String dir = "d:/test";
+		String zip = "d:/test.zip";
+		try (OutputStream out = new FileOutputStream(zip)){
+			//实际应用中, out 为 HttpServletResponse.getOutputStream
+			ZipUtil.zip(out, Charset.defaultCharset(), false, null, new File(dir));
+		} catch (Exception e) {
+			e.printStackTrace();
+		}
+	}
 }