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该文章地址：https://blog.yookingh.cn/dev/190809-webSocket.html
前言
什么是webSocket
WebSocket是一种在单个TCP连接上进行全双工通信的协议。WebSocket通信协议于2011年被IETF定为标准RFC 6455，并由RFC7936补充规范。WebSocket API也被W3C定为标准。
WebSocket使得客户端和服务器之间的数据交换变得更加简单，允许服务端主动向客户端推送数据。在WebSocket API中，浏览器和服务器只需要完成一次握手，两者之间就直接可以创建持久性的连接，并进行双向数据传输。
——摘自百度百科-
应用场景
App与服务器长连接，一般用于通讯。
实践
框架引入
框架路径：
Java-WebSocket
OkHttp-GithubPage
//implementation "org.java-websocket:Java-WebSocket:1.4.0"//
//改用 square项目
implementation 'com.squareup.okhttp3:okhttp:4.0.1'
implementation 'com.squareup.okhttp3:logging-interceptor:4.0.1'
创建Utils类
/**
* @param url webSocket 服务链接
* @param listener webSocket 消息回调 - 这里直接使用okhttp的回调/可根据需求另行封装
*/
class WebSocketUtils(private val url: String, private val listener: WebSocketListener)
初始化webSocket
private const val TAG: String = "WebSocketLog"//日志抬头
private const val READ_TIMEOUT: Long = 30//读取超时
private const val WRITE_TIMEOUT: Long = 30//写入超时
private const val CONNECT_TIMEOUT: Long = 30//连接超时
private val okHttpClient: OkHttpClient
private var webSocket: RealWebSocket
init{
//引入log日志
val interceptor = HttpLoggingInterceptor(
object : HttpLoggingInterceptor.Logger {
override fun log(message: String) {
Log.d(TAG, message)
}
}
)
interceptor.level = HttpLoggingInterceptor.Level.BODY//日志等级
okHttpClient = OkHttpClient.Builder()
.readTimeout(READ_TIMEOUT, TimeUnit.SECONDS)//设置读取超时时间
.writeTimeout(WRITE_TIMEOUT, TimeUnit.SECONDS)//设置写的超时时间
.connectTimeout(CONNECT_TIMEOUT, TimeUnit.SECONDS)//设置连接超时时间
.retryOnConnectionFailure(true)//断线重连
.addInterceptor(interceptor)//添加拦截器
.build()
val request: Request = Request.Builder().url(url).build()
//创建webSocket
webSocket = okHttpClient.newWebSocket(request, listener) as RealWebSocket
}
基本方法封装
//发送
fun send(message: String) {
//这里message为与后台约定的内容 建议使用Json样式
val isSend = webSocket.send(message)
//发送失败可以做重新发送
Log.d(TAG, "send-->isSend:$isSend message:$message")
}
//重连
fun reConnect(url: String) {//替换了url
webSocket.cancel()
val request: Request = Request.Builder().url(url).build()
webSocket = okHttpClient.newWebSocket(request, listener) as RealWebSocket
}
fun reConnect() {//未替换url
reConnect(url)
}
//断开
fun cancel() {
webSocket.cancel()
}
心跳机制处理
心跳的启动与关闭封装
private const val WHAT_HEART: Int = 0//handler-what
private const val DEFAULT_HEART_TIME: Long = 60//默认心跳时间
/**
* @param heartMessage 向后台服务发送的心跳消息
* @param current 间隔时间
*/
fun startHeart(heartMessage: String, current: Long?) {
this.heartMessage = heartMessage
heartTime = current!!
handler.sendEmptyMessage(WHAT_HEART)
}
//停止心跳
fun endHeart() {
handler.removeMessages(WHAT_HEART)
}
心跳Handler
//这里使用静态内部类 防止内存泄漏
companion object {
private class WithoutLeakHandler(wsu: WebSocketUtils) : Handler() {
private val mWsu: WeakReference<WebSocketUtils> = WeakReference(wsu)
override fun handleMessage(msg: Message?) {
super.handleMessage(msg)
val webSocketUtils = mWsu.get()!!
//调用发送方法向后台服务发送心跳信息
webSocketUtils.send(webSocketUtils.heartMessage)
//webSocketUtils.heartTime之后再次发送心跳信息
msg!!.target.sendEmptyMessageDelayed(WHAT_HEART, webSocketUtils.heartTime)
}
}
}
private var handler: Handler = WithoutLeakHandler(this)
方法调用
webSocketUtils = WebSocketUtils(url,object : WebSocketListener() {
override fun onOpen(webSocket: WebSocket, response: Response) {
super.onOpen(webSocket, response)
Log.d(TAG, "onOpen")
}
override fun onMessage(webSocket: WebSocket, text: String) {
super.onMessage(webSocket, text)
Log.d(TAG, "onMessage-->text:$text")
}
override fun onMessage(webSocket: WebSocket, bytes: ByteString) {
super.onMessage(webSocket, bytes)
Log.d(TAG, "onMessage-->bytes:$bytes")
}
override fun onClosed(webSocket: WebSocket, code: Int, reason: String) {
super.onClosed(webSocket, code, reason)
Log.d(TAG, "onClosed-->code:$code\treason$reason")
webSocketUtils.endHeart()//停止心跳
}
override fun onClosing(webSocket: WebSocket, code: Int, reason: String) {
super.onClosing(webSocket, code, reason)
Log.d(TAG, "onClosing-->code:$code\treason$reason")
webSocketUtils.endHeart()//停止心跳
}
override fun onFailure(webSocket: WebSocket, t: Throwable, response: Response?) {
super.onFailure(webSocket, t, response)
Log.d(TAG, "onFailure-->throwable:$t")
//webSocketUtils.reConnect()
webSocketUtils.endHeart()//停止心跳
}
})
webSocketUtils.startHeart("心跳消息", 1000)//启动心跳
Demo
补充
建议使用Service进行webSocket连接
