最近公司在搞一个项目刚好需要用到web socket技术来实现实时数据的传输，因为之前也没接触过，所以捣鼓了好些天，最近恰巧有空就写写。有误的地方还请大牛们能及时指正。
项目背景：基于spring+spring MVC+mybatis框架的maven项目
服务端：
1、添加Jar包依赖：
<dependency>
<groupId>javax.websocket</groupId>
<artifactId>javax.websocket-api</artifactId>
<version>1.1</version>
<scope>provided</scope>
</dependency>
2、创建一个Web Socket服务端类MyWebSocketServer，并在类前添加@ServerEndpoint(value = "/websocket")注解，@ServerEndpoint(value = "/websocket")注释端点表示将 WebSocket 服务端运行在 ws://[Server 端 IP 或域名]:[Server 端口]/项目名/websocket 的访问端点
3、实现onOpen、onClose、onMessage、onError等方法
实例代码：
MyWebSocketServer 类
import java.io.IOException;
import javax.websocket.EncodeException;
import javax.websocket.OnClose;
import javax.websocket.OnError;
import javax.websocket.OnMessage;
import javax.websocket.OnOpen;
import javax.websocket.Session;
import javax.websocket.server.PathParam;
import javax.websocket.server.ServerEndpoint;
import org.apache.commons.lang.StringUtils;
import org.apache.log4j.Logger;
import net.sf.json.JSONObject;
@ServerEndpoint(value = "/websocket")
public class MyWebSocketServer {
private Logger logger = Logger.getLogger(MyWebSocketServer.class);
private Session session;
/**
* 连接建立后触发的方法
*/
@OnOpen
public void onOpen(Session session){
this.session = session;
logger.info("onOpen"+session.getId());
WebSocketMapUtil.put(session.getId(),this);
}
/**
* 连接关闭后触发的方法
*/
@OnClose
public void onClose(){
//从map中删除
WebSocketMapUtil.remove(session.getId());
logger.info("====== onClose:"+session.getId()+" ======");
}
/**
* 接收到客户端消息时触发的方法
*/
@OnMessage
public void onMessage(String params,Session session) throws Exception{
//获取服务端到客户端的通道
MyWebSocketServer myWebSocket = WebSocketMapUtil.get(session.getId());
logger.info("收到来自"+session.getId()+"的消息"+params);
String result = "收到来自"+session.getId()+"的消息"+params;
//返回消息给Web Socket客户端（浏览器）
myWebSocket.sendMessage(1,”成功！”,result);
}
/**
* 发生错误时触发的方法
*/
@OnError
public void onError(Session session,Throwable error){
logger.info(session.getId()+"连接发生错误"+error.getMessage());
error.printStackTrace();
}
public void sendMessage(int status,String message,Object datas) throws IOException{
JSONObject result = new JSONObject();
result.put("status", status);
result.put("message", message);
result.put("datas", datas);
this.session.getBasicRemote().sendText(result.toString());
}
}
WebSocketMapUtil 工具类
import java.util.Collection;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
public class WebSocketMapUtil {
public static ConcurrentMap<String, MyWebSocketServer> webSocketMap = new ConcurrentHashMap<>();
public static void put(String key, MyWebSocketServer myWebSocketServer){
webSocketMap.put(key, myWebSocketServer);
}
public static MyWebSocketServer get(String key){
return webSocketMap.get(key);
}
public static void remove(String key){
webSocketMap.remove(key);
}
public static Collection<MyWebSocketServer> getValues(){
return webSocketMap.values();
}
}
客户端：
1、添加Jar包依赖：
<dependency>
<groupId>org.java-websocket</groupId>
<artifactId>Java-WebSocket</artifactId>
<version>1.3.8</version>
</dependency>
2、创建Web Socket客户端类MyWebSocketClient，并继承WebSocketClient
3、实现构造器，重写onOpen、onClose、onMessage、onError等方法
实例代码：
MyWebSocketClient 类
import java.net.URI;
import org.activiti.engine.impl.util.json.JSONObject;
import org.apache.log4j.Logger;
import org.java_websocket.client.WebSocketClient;
import org.java_websocket.handshake.ServerHandshake;
public class MyWebSocketClient extends WebSocketClient{
Logger logger = Logger.getLogger(MyWebSocketClient.class);
public MyWebSocketClient(URI serverUri) {
super(serverUri);
}
@Override
public void onOpen(ServerHandshake arg0) {
// TODO Auto-generated method stub
logger.info("------ MyWebSocket onOpen ------");
}
@Override
public void onClose(int arg0, String arg1, boolean arg2) {
// TODO Auto-generated method stub
logger.info("------ MyWebSocket onClose ------");
}
@Override
public void onError(Exception arg0) {
// TODO Auto-generated method stub
logger.info("------ MyWebSocket onError ------");
}
@Override
public void onMessage(String arg0) {
// TODO Auto-generated method stub
logger.info("-------- 接收到服务端数据： " + arg0 + "--------");
}
}
MyTest 测试类
public class MyTest{
public static void main(String[] arg0){
MyWebSocketClient myClient = new MyWebSocketClient("此处为websocket服务端URI");
// 往websocket服务端发送数据
myClient.send("此为要发送的数据内容");