ideal 调用socket可以 Android 调用socket超时空指针 idea websocket

环境

window7，IntelliJ IDEA 2019.2 x64

 

背景：利用IntelliJ来搭建springboot框架，之后来实现websocket的功能。websocket只是实现了画面上的消息的互相推送的功能，即在不刷新网页的情况下，把必要的消息推送到你的网页上面。

利用IntelliJ来搭建spring的web框架。

1. 下载IntelliJ的安装包，之后正常安装即可

2. 打开IDE，创建一个web功能

具体操作如下

 

 

点击finish之后，自己的springweb的工程创建完了。

构建自己的websocket程序

工程的构成如下图

创建自己的control文件

LoginControl类是为了加载首页，找到webSocketIndex.html文件，但此时的application.properties文件里面要引用【spring.thymeleaf.prefix=classpath:/templates/】否则找不到路径

package com.control;

import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.servlet.ModelAndView;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

@EnableAutoConfiguration
@RestController
public class LoginControl {

    @RequestMapping("login")
    public ModelAndView home(Model model, HttpServletRequest request, HttpServletResponse response) throws Exception {
        String userName = "Jef";
        int count = 100;
　　　　// 固定的写法
        ModelAndView mv = new ModelAndView("webSocketIndex");
        return mv;
    }
}

 

application.properties文件

spring.thymeleaf.prefix=classpath:/templates/
server.port=8081

pom文件

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.7.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example</groupId>
    <artifactId>demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>demo</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-websocket</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-thymeleaf</artifactId>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

WebSocketServer文件

package com.control;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Component;

import javax.websocket.*;
import javax.websocket.server.PathParam;
import javax.websocket.server.ServerEndpoint;
import java.io.IOException;
import java.util.List;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.CopyOnWriteArraySet;

//@ServerEndpoint(value ="/WebSocket/{id}/{name}")
@ServerEndpoint(value ="/WebSocket")
@Component
public class WebSocketServer {
    //静态变量，用来记录当前在线连接数。应该把它设计成线程安全的。
    private static int onlineCount = 0;

    //concurrent包的线程安全Set，用来存放每个客户端对应的MyWebSocket对象。
    private static CopyOnWriteArraySet<WebSocketServer> webSocketSet = new CopyOnWriteArraySet<WebSocketServer>();

    private static ConcurrentHashMap<String, List<WebSocketServer>> webSocketMap =
            new ConcurrentHashMap<>(3);

    //与某个客户端的连接会话，需要通过它来给客户端发送数据
    private Session session;


    private static final Logger LOGGER = LoggerFactory.getLogger(WebSocketServer.class);

    @OnOpen
    public void onOpen(Session session) throws Exception {

        this.session = session;
        System.out.println(this.session.getId());
        webSocketSet.add(this);     //加入set中
        addOnlineCount();           //在线数加1
        System.out.println("有新连接加入！当前在线人数为" + getOnlineCount());
        LOGGER.info("Open a websocket. id={}", "12");

//        try {
//            sendMessage(CommonConstant.CURRENT_WANGING_NUMBER.toString());
//        } catch (IOException e) {
//            System.out.println("IO异常");
//        }
    }

    /**
     * 连接关闭调用的方法
     */
    @OnClose
    public void onClose() {
        webSocketSet.remove(this);  //从set中删除
        subOnlineCount();           //在线数减1
        System.out.println("有一连接关闭！当前在线人数为" + getOnlineCount());
        LOGGER.info("Close a websocket. ");
    }

    /**
     * 收到客户端消息后调用的方法
     *
     * @param message 客户端发送过来的消息*/
    @OnMessage
    public void onMessage(String message, Session session) {
        System.out.println("来自客户端的消息:" + message);
        LOGGER.info("Receive a message from client: " + message);

        //群发消息
        for (WebSocketServer item : webSocketSet) {
            try {
                item.sendMessage(message);
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    /**
     * 发生错误时调用
     */
     @OnError
     public void onError(Session session, Throwable error) {
        System.out.println("发生错误");
        LOGGER.error("Error while websocket. ", error);
        error.printStackTrace();
     }


     public void sendMessage(String message) throws IOException {
     this.session.getBasicRemote().sendText(message);
     //this.session.getAsyncRemote().sendText(message);
     }


     /**
      * 群发自定义消息
      * */
    public static void sendInfo(String message) throws IOException {
        for (WebSocketServer item : webSocketSet) {
            try {
                item.sendMessage(message);
            } catch (IOException e) {
                continue;
            }
        }
    }

    public static synchronized int getOnlineCount() {
        return onlineCount;
    }

    public static synchronized void addOnlineCount() {
        WebSocketServer.onlineCount++;
    }

    public static synchronized void subOnlineCount() {
        WebSocketServer.onlineCount--;
    }
}

html5文件

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
Welcome<br/>
<input id="text" type="text" />
<button onclick="connect()">Connect</button>
<button onclick="send()">Send</button>
<button onclick="closeWebSocket()">Close</button>
<div id="message">
</div>
</body>

<script type="text/javascript">
    var websocket = null;

    //判断当前浏览器是否支持WebSocket
    if('WebSocket' in window){
        debugger
        websocket = new WebSocket("ws://localhost:8081/WebSocket");
    }
    else{
        alert('Not support websocket')
    }

    //连接发生错误的回调方法
    websocket.onerror = function(){
    debugger
        setMessageInnerHTML("error");
    };

    //连接成功建立的回调方法
    websocket.onopen = function(event){
    debugger
        setMessageInnerHTML("open");
    }

    //接收到消息的回调方法
    websocket.onmessage = function(event){
    debugger
        setMessageInnerHTML(event.data);
    }

    //连接关闭的回调方法
    websocket.onclose = function(){
        setMessageInnerHTML("close");
    }

    //监听窗口关闭事件，当窗口关闭时，主动去关闭websocket连接，防止连接还没断开就关闭窗口，server端会抛异常。
    window.onbeforeunload = function(){
        websocket.close();
    }

    //将消息显示在网页上
    function setMessageInnerHTML(innerHTML){
        document.getElementById('message').innerHTML += innerHTML + '<br/>';
    }

    //关闭连接
    function closeWebSocket(){
        websocket.close();
    }

    //发送消息
    function send(){
        var message = document.getElementById('text').value;
        websocket.send(message);
    }
</script>
</html>

在做的过程中遇到的问题是【websocket = new WebSocket("ws://localhost:8081/WebSocket");】总是访问不到，这时你要确认你的【ws://localhost:8081/WebSocket】是否写错

自己检查一下即可。

运行

利用Google浏览器和IE浏览器打开网页http://localhost:8081/login，效果如下

Google浏览器

IE浏览器

 

Google浏览器

IE浏览器