演进之路:原生Android框架不好用 ---- HttpUrlConnect 和 Apache HTTPClient
第一版 底层使用HTTPURLConnect
第二版 Square构建 从Android4.4开始
基本使用:
val okhttp = OkHttpClient()
val request = Request.Builder()
.url("http://www.baidu.com")
.build()
okhttp.newCall(request)
.enqueue(object : okhttp3.Callback{
override fun onFailure(call: okhttp3.Call, e: IOException) {
Log.e("--->",e.message!!)
}
override fun onResponse(call: okhttp3.Call, response: okhttp3.Response) {
Log.e("--->",response.body!!.string())
}
})
//enqueue Call接口定义的抽象方法
//newCall RealCall创建出 有三个参数 1 okhttpclient 2.quest originnalRequest 3. forWebSocket //Booleaan
//WebSocket 是通过http创建连接
//
override fun enqueue(responseCallback: Callback) {
check(executed.compareAndSet(false, true)) { "Already Executed" }
callStart()
//dispatcher 用来做线程调度 管理 Executor 线程池
//MaxRequests = 64 最大64个线程
//MaxRequestPerHost = 5 最多同一主机线程 5
client.dispatcher.enqueue(AsyncCall(responseCallback))
}
override fun isExecuted(): Boolean = executed.get()
private fun callStart() {
//跟踪错误分析和记录
this.callStackTrace = Platform.get().getStackTraceForCloseable("response.body().close()")
//监听一系列事件 连接建立 断开连接 报文 head body 发送等
eventListener.callStart(this)
}
@get:Synchronized var maxRequests = 64 最多连接数量 64
@get:Synchronized var maxRequestsPerHost = 5 同一主机 5
internal fun enqueue(call: AsyncCall) {
synchronized(this) {
readyAsyncCalls.add(call)
// Mutate the AsyncCall so that it shares the AtomicInteger of an existing running call to
// the same host.
if (!call.call.forWebSocket) {
val existingCall = findExistingCallWithHost(call.host)
if (existingCall != null) call.reuseCallsPerHostFrom(existingCall)
}
}
promoteAndExecute()
}
同步方法,Deque 双向队列
AsyncCall 共享变量 记录连接数等
if (!call.call.forWebSocket) { //记录数量 val existingCall = findExistingCallWithHost(call.host) if (existingCall != null) call.reuseCallsPerHostFrom(existingCall) }
private fun promoteAndExecute(): Boolean {
this.assertThreadDoesntHoldLock()
val executableCalls = mutableListOf()
val isRunning: Boolean
synchronized(this) {
val i = readyAsyncCalls.iterator()
while (i.hasNext()) {
val asyncCall = i.next()
if (runningAsyncCalls.size >= this.maxRequests) break // Max capacity.
if (asyncCall.callsPerHost.get() >= this.maxRequestsPerHost) continue // Host max capacity.
i.remove()
asyncCall.callsPerHost.incrementAndGet()
executableCalls.add(asyncCall)
runningAsyncCalls.add(asyncCall)
}
isRunning = runningCallsCount() > 0
}
for (i in 0 until executableCalls.size) {
val asyncCall = executableCalls[i]
asyncCall.executeOn(executorService)
}
return isRunning
}
promoteAndExecute 准备执行函数
readyAsyncCalls 没有执行过的请求 不会超出限制 64 or 5
executableCalls 添加到calls 然后取出遍历 执行 executeOn
val i = readyAsyncCalls.iterator() 遍历被执行的call
if (runningAsyncCalls.size >= this.maxRequests) break // Max capacity. if (asyncCall.callsPerHost.get() >= this.maxRequestsPerHost) continue // Host max capacity. 超出连接限制的数量 终止请求
i.remove() //移除当前请求 asyncCall.callsPerHost.incrementAndGet() executableCalls.add(asyncCall) runningAsyncCalls.add(asyncCall)
runningAsyncCalls 正在执行的Call
for (i in 0 until executableCalls.size) {
val asyncCall = executableCalls[i]
遍历准备执行的call 然后调用executeOn
asyncCall.executeOn(executorService)
}
Okhttp enqueue ----> newCall ---> RealCall enqueue ------> 执行 dispatcher . enqueue ----> 添加到readyAsyncCalls ----> promoteAndExecute ---executeOn 执行
fun executeOn(executorService: ExecutorService) {
client.dispatcher.assertThreadDoesntHoldLock()
var success = false
try {
executorService.execute(this)
success = true
} catch (e: RejectedExecutionException) {
val ioException = InterruptedIOException("executor rejected")
ioException.initCause(e)
noMoreExchanges(ioException)
responseCallback.onFailure(this@RealCall, ioException)
} finally {
if (!success) {
client.dispatcher.finished(this) // This call is no longer running!
}
}
}
executorService dispatcher 内部类管理的对象 线程调度 参数是runnable
executorService.execute(this) 线程切换到后台线程 Async 实现了Runnable
线程调度
override fun run() {
threadName("OkHttp ${redactedUrl()}") {
var signalledCallback = false
timeout.enter()
try {
val response = getResponseWithInterceptorChain()
signalledCallback = true
responseCallback.onResponse(this@RealCall, response)
} catch (e: IOException) {
if (signalledCallback) {
// Do not signal the callback twice!
Platform.get().log("Callback failure for ${toLoggableString()}", Platform.INFO, e)
} else {
responseCallback.onFailure(this@RealCall, e)
}
} catch (t: Throwable) {
cancel()
if (!signalledCallback) {
val canceledException = IOException("canceled due to $t")
canceledException.addSuppressed(t)
responseCallback.onFailure(this@RealCall, canceledException)
}
throw t
} finally {
client.dispatcher.finished(this)
}
}
}
val response = getResponseWithInterceptorChain() 获取相应
getResponseWithInterceptorChain 请求数据的方法封装
responseCallback 代码里声明传入的Callback