snapshotService log the actual port (#1756)

* snapshotService log the actual port

* snapshotService log the actual port
diff --git a/elasticjob-lite/elasticjob-lite-core/src/main/java/org/apache/shardingsphere/elasticjob/lite/internal/snapshot/SnapshotService.java b/elasticjob-lite/elasticjob-lite-core/src/main/java/org/apache/shardingsphere/elasticjob/lite/internal/snapshot/SnapshotService.java
index f27cbc0..d2a1131 100644
--- a/elasticjob-lite/elasticjob-lite-core/src/main/java/org/apache/shardingsphere/elasticjob/lite/internal/snapshot/SnapshotService.java
+++ b/elasticjob-lite/elasticjob-lite-core/src/main/java/org/apache/shardingsphere/elasticjob/lite/internal/snapshot/SnapshotService.java
@@ -62,16 +62,16 @@
      */
     public void listen() {
         try {
-            log.info("ElasticJob: Snapshot service is running on port '{}'", port);
-            openSocket(port);
+            log.info("ElasticJob: Snapshot service is running on port '{}'", openSocket(port));
         } catch (final IOException ex) {
             log.error("ElasticJob: Snapshot service listen failure, error is: ", ex);
         }
     }
     
-    private void openSocket(final int port) throws IOException {
+    private int openSocket(final int port) throws IOException {
         serverSocket = new ServerSocket(port);
-        String threadName = String.format("elasticjob-snapshot-service-%d", port);
+        int localPort = serverSocket.getLocalPort();
+        String threadName = String.format("elasticjob-snapshot-service-%d", localPort);
         new Thread(() -> {
             while (!closed) {
                 try {
@@ -84,6 +84,7 @@
                 }
             }
         }, threadName).start();
+        return localPort;
     }
     
     private boolean isIgnoredException() {