HttpClient設置連接超時時間

使用HttpClient，一般都需要設置連接超時時間和獲取數據超時時間。這兩個參數很重要，目的是為了防止訪問其他http時，由於超時導致自己的應用受影響。

4.5版本中，這兩個參數的設置都抽象到了RequestConfig中，由相應的Builder構建，具體的例子如下:

CloseableHttpClient httpclient = HttpClients.createDefault(); HttpGet httpGet = new HttpGet("http://www.baidu.com"); RequestConfig requestConfig = RequestConfig.custom() .setConnectTimeout(5000).setConnectionRequestTimeout(1000) .setSocketTimeout(5000).build(); httpGet.setConfig(requestConfig); CloseableHttpResponse response = null; try { response = httpclient.execute(httpGet); } catch (IOException e) { e.printStackTrace(); } System.out.println("得到的結果:" + response.getStatusLine());//得到請求結果
HttpEntity entity = response.getEntity();//得到請求回來的數據
String s = EntityUtils.toString(response.getEntity(), "UTF-8"); System.out.println(s);

setConnectTimeout：設置連接超時時間，單位毫秒。

setConnectionRequestTimeout：設置從connect Manager獲取Connection 超時時間，單位毫秒。這個屬性是新加的屬性，因為目前版本是可以共享連接池的。

setSocketTimeout：請求獲取數據的超時時間，單位毫秒。 如果訪問一個接口，多少時間內無法返回數據，就直接放棄此次調用。

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一、連接超時：connectionTimeout

指的是連接一個url的連接等待時間。比如連google.

org.apache.http.conn.ConnectTimeoutException: Connect to www.google.com:80 [www.google.com/203.98.7.65] failed: connect timed out
    at org.apache.http.impl.conn.HttpClientConnectionOperator.connect(HttpClientConnectionOperator.java:132)
    at org.apache.http.impl.conn.PoolingHttpClientConnectionManager.connect(PoolingHttpClientConnectionManager.java:318)
    at org.apache.http.impl.execchain.MainClientExec.establishRoute(MainClientExec.java:363)
    at org.apache.http.impl.execchain.MainClientExec.execute(MainClientExec.java:219)
    at org.apache.http.impl.execchain.ProtocolExec.execute(ProtocolExec.java:195)
    at org.apache.http.impl.execchain.RetryExec.execute(RetryExec.java:86)
    at org.apache.http.impl.execchain.RedirectExec.execute(RedirectExec.java:108)
    at org.apache.http.impl.client.InternalHttpClient.doExecute(InternalHttpClient.java:184)
    at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:82)
    at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:106)
    at Test.main(Test.java:22)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at com.intellij.rt.execution.application.AppMain.main(AppMain.java:144)
Caused by: java.net.SocketTimeoutException: connect timed out
    at java.net.DualStackPlainSocketImpl.waitForConnect(Native Method)
    at java.net.DualStackPlainSocketImpl.socketConnect(DualStackPlainSocketImpl.java:85)
    at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:350)
    at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:206)
    at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:188)
    at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:172)
    at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
    at java.net.Socket.connect(Socket.java:589)
    at org.apache.http.conn.socket.PlainConnectionSocketFactory.connectSocket(PlainConnectionSocketFactory.java:72)
    at org.apache.http.impl.conn.HttpClientConnectionOperator.connect(HttpClientConnectionOperator.java:123)
    ... 15 more

二、讀取數據超時：SocketTimeout

指的是連接上一個url，獲取response的返回等待時間。

測試的時候連接url可以是本地開啟的一個url，http://localhost:8080/firstTest.htm?method=test

當訪問到這個鏈接時，線程sleep一段時間，來模擬返回response超時。

@RequestMapping(params = "method=test")
public String testMethod(ModelMap model) {
    try {
        Thread.sleep(3000);
    } catch (InterruptedException e) {
        e.printStackTrace();
    }
    System.out.println("call testMethod method.");
    model.addAttribute("name", "test method");
    return "test";
}

參考：

http://blog.csdn.net/hi_kevin/article/details/32316171