由于安卓资源管理器展示的路径不尽相同,各种软件保存文件的位置也不一定一样.对于普通用户上传文件时,查找文件可能是一个麻烦的事情.后来想到了一个办法,使用pc端进行辅助上传.

实现思路

1. pc端与服务器建立websocket连接;
2. 服务器将sessionId传递到pc端;
3. pc端生成二维码;
4. 手机端扫描二维码,读取pc端sessionId;
5. 手机端与服务器建立websocket连接;
6. 手机端将fileId（后面再解释）、pc端sessionId、token等参数传递给服务器;
7. 服务器更新pc端session 对应的fileId;
8. 服务器将fileId、token等发送到pc端；
9. pc使用token、fileId等请求文件列表并进行展示；
10. 手机端、pc端进行文件修改后，向服务器发送给更新信号，服务器将更新信号转发到对端。

1.0 实现

定义web与客户端通信数据类型和数据格式

1. 定义web与客户端通信数据类型

public class MsgType {public static final int UPDATE = 0; //提示客户端数据发生更新public static final int REQ = 1; //发送/接受fileId等字段public static final int SELF = 3; //建立连接后,web端发送client其sessionIdpublic static final int ERR_SESSION = 4; //提示session不存在或已close public static final int HEART_BEAT = 100; //心跳包
}

2. 定义web与客户端通信数据格式

@Data
public class MsgData {private int type;  //对应 MsgTypeprivate String sessionId; //SELF 对应自身sessionId; REQ 对应pc端sessionId;private String fileId; //建立连接后,向pc端发送fileId等字段

web端websocket实现

创建spring-boot项目,添加web\websocket相关依赖

使用maven引入websocket依赖;

        <dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-websocket</artifactId></dependency>

配置websocket和访问路径的映射关系

@Configuration   //配置websocket和访问路径的映射关系
@EnableWebSocket // 全局开启WebSocket支持
public class WebSocketConfig implements WebSocketConfigurer {@Overridepublic void registerWebSocketHandlers(WebSocketHandlerRegistry registry) {registry.addHandler(new WebSocketServer(), "/websocket").setAllowedOrigins("*");}
}

web端对客户端数据的管理

1. 定义web管理session的数据结构

@Data
public class SessionData {private int sessionType; // 1 master(app). 0 pcprivate String fileId; //pc会话IDprivate WebSocketSession session;private String sessionId;//虽然可以通过session.getId()获取到sessionId,但session关闭后,读取就会报错

web端对session的管理逻辑

1. 新创建的连接添加到链表上,web向客户端发送SELF,告知其对应的sessionId;

2. 断开连接时,如果是pc端session直接从链表中删除,如果是app端session,将其他相同fileId的session全部关闭并从链表删除;

3. 接收到新消息后,根据消息类型进行分类处理:

   1. 心跳包,则直接返回;
   2. REQ app发送的fileId\pc端sessionId等字段,修改sessions上app连接和pc端SessionData内的fileId字段;
      并将fileId等字段发送给pc端;
   3. UPDATE 给所有相同fileId的session发送更新信号;

注意: sessions遍历\删除\添加必须添加synchronized,否则ConcurrentModificationException

package com.example.im.ws;import com.google.gson.Gson;
import lombok.extern.slf4j.Slf4j;
import org.springframework.web.socket.CloseStatus;
import org.springframework.web.socket.TextMessage;
import org.springframework.web.socket.WebSocketSession;
import org.springframework.web.socket.handler.TextWebSocketHandler;import java.util.ArrayList;
import java.util.List;
import java.util.Optional;
import java.util.stream.Collectors;/*** @ClassName WebSocketServer* @Description 处理websocket 连接* @Author guchuanhang* @date 2025/1/25 14:01* @Version 1.0**/@Slf4j
public class WebSocketServer extends TextWebSocketHandler {private final Object syncObject = new Object();private final List<SessionData> sessions =new ArrayList<>();@Overridepublic void afterConnectionEstablished(WebSocketSession session) throws Exception {log.info("New connection established: " + session.getId());SessionData sessionData = new SessionData(session);synchronized (syncObject) {sessions.add(sessionData);}MsgData msgData = new MsgData();msgData.setType(MsgType.SELF);msgData.setSessionId(session.getId());session.sendMessage(new TextMessage(new Gson().toJson(msgData)));}@Overrideprotected void handleTextMessage(WebSocketSession session, TextMessage message)throws Exception {String payload = message.getPayload();log.info("handleTextMessage: " + session.getId());log.info("Received message: " + payload);final MsgData msgData = new Gson().fromJson(payload, MsgData.class);//master 发来的需求.switch (msgData.getType()) {case MsgType.HEART_BEAT: {//heart beatbreak;}case MsgType.REQ: {//set master{SessionData sessionData = null;synchronized (syncObject) {final Optional<SessionData> any = sessions.stream().filter(s -> s.getSessionId().equals(session.getId())).findAny();if (any.isPresent()) {sessionData = any.get();}}if (null != sessionData) {//set master.sessionData.setSessionType(ClientType.MASTER);sessionData.setFileId(msgData.getFileId());}}//set slave{SessionData sessionData = null;synchronized (syncObject) {final Optional<SessionData> any = sessions.stream().filter(s -> s.getSessionId().equals(msgData.getSessionId())).findAny();if (any.isPresent()) {sessionData = any.get();}}if (null != sessionData) {sessionData.setSessionType(ClientType.SALVER);sessionData.setFileId(msgData.getFileId());MsgData msgData1 = new MsgData();msgData1.setType(MsgType.REQ);msgData1.setFileId(msgData.getFileId());sessionData.getSession().sendMessage(new TextMessage(new Gson().toJson(msgData1)));} else {//pc session error.MsgData msgData1 = new MsgData();msgData1.setType(MsgType.ERR_SESSION);session.sendMessage(new TextMessage(new Gson().toJson(msgData1)));}}break;}case MsgType.UPDATE: {//slfSessionData sessionData = null;synchronized (syncObject) {final Optional<SessionData> any = sessions.stream().filter(s -> s.getSessionId().equals(session.getId())).findAny();if (any.isPresent()) {sessionData = any.get();}}if (null != sessionData) {final String fileId = sessionData.getFileId();List<SessionData> collect;synchronized (syncObject) {collect =sessions.stream().filter(s -> (null != s.getFileId() && s.getFileId().equals(fileId)) || (null == s.getSession() || !s.getSession().isOpen())).collect(Collectors.toList());}if (collect.isEmpty()) {return;}List<SessionData> errList = new ArrayList<>();for (SessionData s : collect) {if (null == s.getSession() || !s.getSession().isOpen()) {errList.add(s);continue;}//不需要给自己发送了if (s.getSessionId().equals(session.getId())) {continue;}MsgData msgData1 = new MsgData();msgData1.setType(MsgType.UPDATE);try {s.getSession().sendMessage(new TextMessage(new Gson().toJson(msgData1)));} catch (Exception e) {e.printStackTrace();errList.add(s);}}synchronized (syncObject) {sessions.removeAll(errList);}}break;}}}@Overridepublic void afterConnectionClosed(WebSocketSession session, CloseStatus status) throws Exception {log.info("Connection closed: " + session.getId() + ", Status: " + status);SessionData sessionData = null;synchronized (syncObject) {Optional<SessionData> any = sessions.stream().filter(s -> s.getSessionId().equals(session.getId())).findAny();if (any.isPresent()) {sessionData = any.get();}}if (null == sessionData) {return;}final String fileId = sessionData.getFileId();//slave just ignore and delete.if (ClientType.SALVER == sessionData.getSessionType()) {sessions.remove(sessionData);return;}if (ClientType.MASTER == sessionData.getSessionType()) {List<SessionData> collect;synchronized (syncObject) {collect =sessions.stream().filter(s ->(null != s.getFileId()&& s.getFileId().equals(fileId)) ||(null == s.getSession() || !s.getSession().isOpen())).collect(Collectors.toList());}if (collect.isEmpty()) {return;}for (SessionData s : collect) {final WebSocketSession session1 = s.getSession();if (null == session1 || !session1.isOpen()) {continue;}session1.close();}synchronized (syncObject) {sessions.removeAll(collect);}}}
}

pc端实现

1. 页面创建时创建websocket,销毁时关闭websocket
2. 根据和服务器约定的消息格式 在websocket回调函数onmessage接受数据类型进行二维码生成\文件列表查询等操作
3. 添加心跳机制,让websocket更健壮

fileId是一个key,通过fileId可以查询最新的数据. pc端接受到刷新信号后,请求获取最新数据; pc端更新数据后,发送数据已更新信号.

<template><div v-if="fileId"><div>{{ fileId }}</div><el-button @click="updateData" type="primary">更新数据</el-button><div>发送给服务端更新信号时间: {{ sndUpdateSignalTime }}</div><div>收到服务端更新信号时间: {{ rcvUpdateSignalTime }}</div><div>心跳最新时间: {{ heartBeatSignalTime }}</div><div>服务器返回最新内容: {{ serverContent }}</div></div><div v-else-if="sessionId"><div>sessionId:{{ sessionId }}</div><img width="200px" height="200px" :src="qrCode" alt="QR Code"/></div></template><script>import QRCode from "qrcode";export default {name: "HelloWorld",data() {return {wsuri: "ws://192.168.0.110:7890/websocket",ws: null,sessionId: '',qrCode: null,fileId: '',rcvUpdateSignalTime: '',sndUpdateSignalTime: '',heartBeatSignalTime: '',serverContent: '',heartbeatInterval: null,heartbeatIntervalTime: 3000, // 心跳间隔时间，单位为毫秒}},created() {//页面打开时，初始化WebSocket连接this.initWebSocket()},beforeDestroy() {// 页面销毁时，关闭WebSocket连接this.stopHeartbeat()this.fileId = ''try {this.ws.close()} catch (e) {}this.ws = null;this.sessionId = ''},methods: {// pc端更新附件数据后，向服务器端发送更新信号updateData() {console.error('snd update signal')this.ws.send(JSON.stringify({type: 0}))//格式化为  yyyy-MM-dd HH:mm:ssthis.sndUpdateSignalTime = new Date().toLocaleTimeString()this.resetHeartbeat();},async generateQRCode() {try {this.qrCode = await QRCode.toDataURL(this.sessionId);} catch (error) {console.error('生成二维码时出错:', error);}},// 周期性发送心跳包startHeartbeat() {this.heartbeatInterval = setInterval(() => {if (this.ws && this.ws.readyState === WebSocket.OPEN) {this.ws.send(JSON.stringify({type: 100}))this.heartBeatSignalTime = new Date().toLocaleTimeString()console.error('snd heartbeat signal')} else {this.stopHeartbeat();}}, this.heartbeatIntervalTime);},//在发送或接受数据后,重置下一次发送心跳包的时间resetHeartbeat() {clearInterval(this.heartbeatInterval);this.startHeartbeat();},// 停止发送心跳包stopHeartbeat() {clearInterval(this.heartbeatInterval);},initWebSocket() {let that = this;this.ws = new WebSocket(this.wsuri);this.ws.onopen = () => {this.startHeartbeat();};// 接收后端消息this.ws.onmessage = function (event) {console.error('RECV:' + event.data)that.serverContent = event.data;let parse = JSON.parse(event.data);that.resetHeartbeat();switch (parse.type) {case 0: {console.error('update')that.rcvUpdateSignalTime = new Date().toLocaleTimeString()//TODO. 请求最新数据break;}case 1: {   //fileId list. 接受数据,进行路径跳转console.error('REQ:' + event.data)that.fileId = parse.fileId;//记录并请求最新数据break;}case 3: {that.sessionId = parse.sessionId;that.generateQRCode();break;}}};// 关闭连接时调用this.ws.onclose = function (event) {alert('连接已关闭');that.stopHeartbeat()// 强制刷新页面(created 会调用)location.reload(true)};}}
}
</script><style scoped></style>

OkHttp3建立websocket连接

1. 使用okhttp3建立websocket连接,监听onMessage根据消息类型进行不同的处理;
2. 使用handler 管理心跳包

扫码后, 如果已经建立连接了

package com.example.im.ws;import android.content.Intent;
import android.os.Bundle;
import android.os.Handler;
import android.os.Looper;
import android.os.Message;
import android.text.TextUtils;
import android.widget.EditText;
import android.widget.TextView;import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.appcompat.app.AppCompatActivity;import com.example.im.R;
import com.google.gson.Gson;
import com.google.zxing.integration.android.IntentIntegrator;
import com.google.zxing.integration.android.IntentResult;import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.List;
import java.util.Locale;import okhttp3.OkHttpClient;
import okhttp3.Request;
import okhttp3.WebSocket;
import okhttp3.WebSocketListener;public class HelloActivity extends AppCompatActivity {public static final int MSG_HEART = 0x123;public static final int MSG_INTERVAL = 3000;private WebSocket webSocket;public static final String URL = "ws://192.168.0.110:7890/websocket";private TextView msgView;private List<String> sessionIds = new ArrayList<>();Handler mHandler = new Handler(Looper.getMainLooper()) {@Overridepublic void handleMessage(@NonNull Message msg) {super.handleMessage(msg);if (MSG_HEART == msg.what) {MsgData msgData = new MsgData();msgData.setType(MsgType.HEART_BEAT);webSocket.send(new Gson().toJson(msgData));msgView.append(getNowDate() + ":发送消息 heart beat\n");mHandler.sendMessageDelayed(mHandler.obtainMessage(MSG_HEART), MSG_INTERVAL);}}};@Overrideprotected void onCreate(@Nullable Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);msgView = findViewById(R.id.tv_msg);findViewById(R.id.btn_scan).setOnClickListener(v -> {scanQRCode();});findViewById(R.id.btn_update).setOnClickListener(v -> {MsgData msgData = new MsgData();msgData.setType(MsgType.UPDATE);webSocket.send(new Gson().toJson(msgData));});}@Overrideprotected void onDestroy() {mHandler.removeCallbacksAndMessages(null);super.onDestroy();}private void scanQRCode() {IntentIntegrator integrator = new IntentIntegrator(this);integrator.setDesiredBarcodeFormats(IntentIntegrator.QR_CODE);integrator.setPrompt("提示");integrator.setCameraId(0);  // 使用后置摄像头integrator.setBeepEnabled(false);integrator.setBarcodeImageEnabled(true);integrator.initiateScan();}@Overrideprotected void onActivityResult(int requestCode, int resultCode, Intent data) {IntentResult result = IntentIntegrator.parseActivityResult(requestCode, resultCode, data);if (result != null && !TextUtils.isEmpty(result.getContents())) {String sessionId = result.getContents();if (sessionIds.contains(sessionId)) {return;}sessionIds.add(sessionId);//startif (null == webSocket) {OkHttpClient client = new OkHttpClient();Request request = new Request.Builder().url(URL).build();webSocket = client.newWebSocket(request, new MyWebSocketListener());} else {//这样可以实现扫多个pc端. 同时与多个pc端通信MsgData msgData = new MsgData();msgData.setSessionId(sessionId);msgData.setType(MsgType.REQ);msgData.setFileId("123");webSocket.send(new Gson().toJson(msgData));}}super.onActivityResult(requestCode, resultCode, data);}private String getNowDate() {SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss",Locale.getDefault());return simpleDateFormat.format(new java.util.Date());}private class MyWebSocketListener extends WebSocketListener {@Overridepublic void onOpen(WebSocket webSocket, okhttp3.Response response) {// 连接成功msgView.append(getNowDate() + ":连接成功\n");MsgData msgData = new MsgData();msgData.setSessionId(sessionIds.get(sessionIds.size() - 1));msgData.setType(MsgType.REQ);msgData.setFileId("123");webSocket.send(new Gson().toJson(msgData));mHandler.sendMessageDelayed(mHandler.obtainMessage(MSG_HEART), MSG_INTERVAL);}@Overridepublic void onMessage(WebSocket webSocket, String text) {msgView.append(getNowDate() + ":接受消息" + text + "\n");mHandler.removeMessages(MSG_HEART);mHandler.sendMessageDelayed(mHandler.obtainMessage(MSG_HEART), MSG_INTERVAL);}@Overridepublic void onFailure(WebSocket webSocket, Throwable t, okhttp3.Response response) {// 连接失败msgView.append(getNowDate() + ":失败" + t.getMessage() + "\n");}}
}

2.0版本

上面的实现确实简单.下面结合实际的系统架构进行适配一下.

spring-boot放到nginx后面

nginx常用来进行负载均衡\防火墙\反向代理等等,这种情况比较常见.

	map $http_upgrade $connection_upgrade { default upgrade; '' close; } server {listen       7777;server_name  localhost;location / {proxy_pass http://127.0.0.1:7890;proxy_set_header Upgrade $http_upgrade; proxy_set_header Connection $connection_upgrade; }}
}

设置Upgrade\Connection请求头,将访问地址修改为nginx的地址,即可实现nginx代理到spring-boot.

spring-boot 放到gateway后面

也就是所谓的spring-cloud 微服务架构.

gateway添加ws协议的路由

        # IM- id: imuri: ws://localhost:7890predicates:- Path=/im/**filters:- StripPrefix=1

访问gateway代理之后的地址,即可实现nginx代理到spring-boot.

spring-boot 放到nginx gateway后面

将前面两者进行结合, nginx保证可以代理到gateway, gateway再路由到spring-boot.

ws升级为wss

网上的做法是, 给gateway\spring-boot都配置证书.

简单才能高效,既然gateway有防火墙验证证书等功能,应用不需要管理才对. nginx要屏蔽这种差异.

配置nginx 直接将wss的请求重写为ws.

nginx重写协议

map $http_upgrade $connection_upgrade { 
default upgrade; 
'' close; 
} 
server
{listen 443 ssl http2;server_name #SSL-START SSL相关配置，请勿删除或修改下一行带注释的404规则ssl on;ssl_certificate   ssl_certificate_key add_header Strict-Transport-Security "max-age=31536000";error_page 497  https://$host$request_uri;location /im/ { proxy_set_header Upgrade $http_upgrade; proxy_set_header Connection $connection_upgrade; proxy_pass http://127.0.0.1:18080/im/;rewrite ^(.*)wss://(.*)$ $1ws://$2 permanent;}
}

这样 wss://域名/im/websocket就可以进行访问了.

其他

源码下载地址: https://gitee.com/guchuanhang/imapplication.git

springboot打包

1. 注释掉skip

<plugin><groupId>org.springframework.boot</groupId><artifactId>spring-boot-maven-plugin</artifactId><version>${spring-boot.version}</version><configuration><mainClass>com.example.im.ImApplication</mainClass><!-- 注释掉,否则不能打包-->
<!--                    <skip>true</skip>--></configuration><executions><execution><id>repackage</id><goals><goal>repackage</goal></goals></execution></executions></plugin>

2. springboot日志
   spring-boot 默认支持logback

@Slf4j
public class WebSocketServer extends TextWebSocketHandler {log.info("New connection established: " + session.getId());

3. bootstrap.yml

bootstrap.yml 是 spring-cloud 配置文件.
application.yml applicaition.properties 是 spring-boot 的配置文件.

4. wss测试工具 wscat

npm install -g wscat  # 安装方式wscat -c wss://www.baidu.com/im/websocket