执行器端口支持随机生成(小于等于0时)，避免端口定义冲突

doc/XXL-JOB官方文档.md

@@ -1053,6 +1053,7 @@ Tips: 历史版本(V1.3.x)目前已经Release至稳定版本, 进入维护阶段
 - 7、底层系统日志级别规范调整，清理遗留代码；
 - 8、修改JobThread捕获Error错误不更新JobLog的问题； 
 - 9、任务注解调整为 “@JobHandler”，与任务注解统一；
+- 10、执行器端口支持随机生成(小于等于0时)，避免端口定义冲突；
 
 ### TODO LIST
 - 1、任务权限管理：执行器为粒度分配权限，核心操作校验权限；
@@ -1075,8 +1076,8 @@ Tips: 历史版本(V1.3.x)目前已经Release至稳定版本, 进入维护阶段
 - 18、JobHandler提供 init/destroy 方法，支持自定义任务线程销毁逻辑；
 - 19、cron表达式的最大长度调整，兼容复杂类型cron；
 - 20、执行器回调地址/日志地址格式兼容，是否已"/"结尾均支持；
-- 21、执行器端口支持随机生成，避免端口冲突；
-- 22、任务单机多线程：提升任务单机并行处理能力；
+- 21、任务单机多线程：提升任务单机并行处理能力；
+
 
 ## 七、其他
 

xxl-job-core/src/main/java/com/xxl/job/core/executor/XxlJobExecutor.java

@@ -9,6 +9,7 @@ import com.xxl.job.core.log.XxlJobFileAppender;
 import com.xxl.job.core.rpc.netcom.NetComClientProxy;
 import com.xxl.job.core.rpc.netcom.NetComServerFactory;
 import com.xxl.job.core.thread.JobThread;
+import com.xxl.job.core.util.NetUtil;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.springframework.beans.BeansException;
@@ -28,7 +29,7 @@ public class XxlJobExecutor implements ApplicationContextAware {
 
     // ---------------------- param ----------------------
     private String ip;
-    private int port = 9999;
+    private int port;
     private String appName;
     private String adminAddresses;
     private String accessToken;
@@ -121,6 +122,10 @@ public class XxlJobExecutor implements ApplicationContextAware {
     // ---------------------- executor-server(jetty) ----------------------
     private NetComServerFactory serverFactory = new NetComServerFactory();
     private void initExecutorServer(int port, String ip, String appName, String accessToken) throws Exception {
+        // valid param
+        port = port>0?port: NetUtil.findAvailablePort(9999);
+
+        // start server
         NetComServerFactory.putService(ExecutorBiz.class, new ExecutorBizImpl());   // rpc-service, base on jetty
         NetComServerFactory.setAccessToken(accessToken);
         serverFactory.start(port, ip, appName); // jetty + registry

xxl-job-core/src/main/java/com/xxl/job/core/util/NetUtil.java

@@ -0,0 +1,70 @@
+package com.xxl.job.core.util;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.IOException;
+import java.net.ServerSocket;
+
+/**
+ * net util
+ *
+ * @author xuxueli 2017-11-29 17:00:25
+ */
+public class NetUtil {
+    private static Logger logger = LoggerFactory.getLogger(NetUtil.class);
+
+    /**
+     * find avaliable port
+     *
+     * @param defaultPort
+     * @return
+     */
+    public static int findAvailablePort(int defaultPort) {
+        int portTmp = defaultPort;
+        while (portTmp < 65535) {
+            if (!isPortUsed(portTmp)) {
+                return portTmp;
+            } else {
+                portTmp++;
+            }
+        }
+        portTmp = defaultPort--;
+        while (portTmp > 0) {
+            if (!isPortUsed(portTmp)) {
+                return portTmp;
+            } else {
+                portTmp--;
+            }
+        }
+        throw new IllegalStateException("no available port.");
+    }
+
+    /**
+     * check port used
+     *
+     * @param port
+     * @return
+     */
+    public static boolean isPortUsed(int port) {
+        boolean used = false;
+        ServerSocket serverSocket = null;
+        try {
+            serverSocket = new ServerSocket(port);
+            used = false;
+        } catch (IOException e) {
+            logger.info(">>>>>>>>>>> xxl-job, port[{}] is in use.", port);
+            used = true;
+        } finally {
+            if (serverSocket != null) {
+                try {
+                    serverSocket.close();
+                } catch (IOException e) {
+                    logger.info("");
+                }
+            }
+        }
+        return used;
+    }
+
+}