< project xmlns = " http : / / maven . apache . org / POM / 4 . 0 . 0 " xmlns : xsi = " http : / / www . w 3 . 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 > < groupId > com . chu < / groupId > < artifactId > webSocket < / artifactId > < version > 1 . 0 - SNAPSHOT < / version > < packaging > war < / packaging > < dependencies > < ! - - servlet - api - - > < dependency > < groupId > javax . servlet < / groupId > < artifactId > javax . servlet - api < / artifactId > < version > 3 . 1 . 0 < / version > < / dependency > < ! - - websocket - api - - > < dependency > < groupId > javax . websocket < / groupId > < artifactId > javax . websocket - api < / artifactId > < version > 1 . 1 < / version > < ! - - 设置作用域默认 compile 编译测试运行 provided 编译测试 runtime 测试运行 test 测试 - - > < scope > provided < / scope > < / dependency > < ! - - JSON 转换 - - > < dependency > < groupId > com . fasterxml . jackson . core < / groupId > < artifactId > jackson - databind < / artifactId > < version > 2 . 7 . 4 < / version > < / dependency > < / dependencies > < ! - - < build > - - > < ! - - < plugins > - - > < ! - - maven 自带的 tomcat 插件需要配置对应的命令 tomcat 7 : run - - > < ! - - < plugin > - - > < ! - - < groupId > org . apache . tomcat . maven < / groupId > - - > < ! - - < artifactId > tomcat 7 - maven - plugin < / artifactId > - - > < ! - - < version > 2 . 2 < / version > - - > < ! - - < configuration > - - > < ! - - < port > 80 < / port > - - > < ! - - < path > / < / path > - - > < ! - - < uriEncoding > UTF - 8 < / uriEncoding > - - > < ! - - < / configuration > - - > < ! - - < / plugin > - - > < ! - - < / plugins > - - > < ! - - < / build > - - > < / project > package com . chu . controller ; import com . fasterxml . jackson . databind . ObjectMapper ; import javax . websocket . * ; import javax . websocket . server . PathParam ; import javax . websocket . server . ServerEndpoint ; import java . io . IOException ; import java . util . HashMap ; import java . util . Map ; / * 小楚想要发送信息给小赵这个信息会先存储在服务器再由服务器发送给小赵 * / @ ServerEndpoint ( " / chat / { name } " ) public class ChatSocket { / / 定义一个 Map 集合，用来存放登陆到服务器的客户名称和 Session private static Map < String , Session > mapMessage = new HashMap < > ( ) ; / / 首先，方法名称可以自定义 / / * 形参 - - - name - - - Session @ OnOpen / / 会话开始 public void onOpen ( @ PathParam ( " name " ) String name , Session session ) { System . out . println ( " onOpen . . . . . " + name ) ; / / key - - - - - name value - - - - - session mapMessage . put ( name , session ) ; } / / 客户机信息处理 * 形参 - - - Session session - - - String message @ OnMessage public void onMessage ( Session session , String message ) { System . out . println ( " onMessage . . . . . " + message ) ; / / 服务端给客户端发消息，走的不是 HTTP 而是直接推送过去了 / / 获取 JSON 对象 ObjectMapper mapper = new ObjectMapper ( ) ; try { / / 获取 JSON 格式的信息 Map < String , String > map = mapper . readValue ( message , Map . class ) ; / / 获取需要发送的信息： content String content = map . get ( " content " ) ; / / 获取接收信息者：小赵 String receive = map . get ( " receive " ) ; / / 从事先定义好的 Map 中获取小赵的 Session Session receiveSession = mapMessage . get ( receive ) ; / / 如果小赵的 Session 为 null if ( receiveSession = = null ) { / / 响应：对方不在线 session . getAsyncRemote ( ) . sendText ( " 对方不在线 " ) ; } else { / / 否则将接收到的信息发送给小赵 receiveSession . getAsyncRemote ( ) . sendText ( content ) ; } } catch ( IOException e ) { e . printStackTrace ( ) ; } } / / 会话结束 @ OnClose public void onClose ( Session session ) { System . out . println ( " onClose . . . . . " + session ) ; } / / 会话出现异常 @ OnError public void onError ( Session session , Throwable e ) { try { e . printStackTrace ( ) ; session . close ( ) ; } catch ( IOException ex ) { ex . printStackTrace ( ) ; } } }" />