Http請求超時的一種處理方法

2019-11-14 15:41:59

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來源：轉載

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URLConnection類常見的超時處理就是調用其setConnectTimeout和setReadTimeout方法：

setConnectTimeout：設置連接主機超時（單位：毫秒）
setReadTimeout：設置從主機讀取數據超時（單位：毫秒）

還有一種比較另類的就是利用java Object對象的wait()和notify()、notifyAll()方法，利用線程的等待和通知機制處理urlConnection的超時，下面直接貼代碼：

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;            }            // 處理HTTP響應的返回狀態信息            int responseCode = reqConnection.getResponseCode();// 響應的代碼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();  　　　　　　　// 讀取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();                                //喚醒線程，跳出等待                wakeUp();            }catch(Exception e)            {                            }        }    }    public String getMessage(){        if (!readOK) //超時        {            return "";        }                if (readLen <= 0) {            return "";        }        return new String(data, 0, readLen);    }    public void startUp() {        this.readingThread = new Thread(this);        readingThread.start();    }    //喚醒線程，不再等待    private synchronized void wakeUp() {        notifyAll();    }    public synchronized void waitForData(int timeout)     {        try {            //指定超時時間，等待connection響應            wait(timeout);        }         catch (Exception e)         {        }                    if (!readOK)        {            isStop = true;            try{                //中斷線程                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連接        reqConnection = (HttpURLConnection) reqUrl.openConnection();        HttpConnProcessThread rec = new HttpConnProcessThread(reqConnection, msg, "post" );        rec.startUp();
　　     // 如果順利連接到并讀完數據，則跳出等待，否則等待超時        rec.waitForData(2000);                String retMessage = rec.getMessage();    }}