Http请求超时的一种处理方法

URLConnection类常见的超时处理就是调用其setConnectTimeout和setReadTimeout方法：

setConnectTimeout：设置连接主机超时（单位：毫秒）

setReadTimeout：设置从主机读取数据超时（单位：毫秒）

还有一种比较另类的就是利用java Object对象的wait()和notify()、notifyAll()方法，利用线程的等待和通知机制处理urlConnection的超时，下面直接贴代码：

public class HttpConnProcessThread implements Runnable {

public boolean isStop = false;

public boolean readOK = false;

private HttpURLConnection reqConnection = null;

public Thread readingThread;

private int readLen;

private String msg = null;

private String reqMethod;

private byte[] data;

/**
* ReadThread constructor comment.
*/
public HttpConnProcessThread(HttpURLConnection reqConnection, String msg, String reqMethod ) {
super();
this.reqConnection = reqConnection;
this.msg = msg;
this.reqMethod = reqMethod;
}

public void run() {

InputStream input = null;
OutputStream output = null;

try{
//reqConnection.connect();
output = reqConnection.getOutputStream();
if ("post".equalsIgnoreCase(reqMethod) && msg != null && msg.length() >0)
{
output.write(msg.getBytes());
output.close();
output = null;
}

// 处理HTTP响应的返回状态信息
int responseCode = reqConnection.getResponseCode();// 响应的代码if( responseCode != 200 )
System.out.println("connect failed! responseCode = " + responseCode + " msg=" + reqConnection.getResponseMessage());

input = reqConnection.getInputStream();

int len;
byte[] buf = new byte[2048];
readLen = 0;
ByteArrayOutputStream outStream = new ByteArrayOutputStream();
　　　　　　　// 读取inputStream
while (!isStop)
{
len = input.read(buf);
if (len <= 0)
{
this.readOK = true;
input.close();
data=outStream.toByteArray();
break;
}
outStream.write(buf, 0, len);
readLen += len;
}
}
catch( IOException ie)
{}
catch(Exception e)
{}
finally
{
try{
reqConnection.disconnect();
if( input != null )
input.close();
if( output != null )
output.close();

//唤醒线程，跳出等待
wakeUp();
}catch(Exception e)
{

}
}
}

public String getMessage(){
if (!readOK) //超时
{
return "";
}

if (readLen <= 0) {
return "";
}
return new String(data, 0, readLen);
}

public void startUp() {
this.readingThread = new Thread(this);
readingThread.start();
}

//唤醒线程，不再等待
private synchronized void wakeUp() {
notifyAll();
}

public synchronized void waitForData(int timeout)
{
try {
//指定超时时间，等待connection响应
wait(timeout);
}
catch (Exception e)
{
}

if (!readOK)
{
isStop = true;
try{
//中断线程
if( readingThread.isAlive() )
readingThread.interrupt();
}catch(Exception e)
{

}
}
}

public static main(String[] args){
String msg="";
URL reqUrl = new URL("http://127.0.0.1:8080/");

// 建立URLConnection连接
reqConnection = (HttpURLConnection) reqUrl.openConnection();
HttpConnProcessThread rec = new HttpConnProcessThread(reqConnection, msg, "post" );
rec.startUp();
　　     // 如果顺利连接到并读完数据，则跳出等待，否则等待超时
rec.waitForData(2000);

String retMessage = rec.getMessage();
}
}