使用HttpClient,一般都需要设置连接超时时间和获取数据超时时间。这两个参数很重要,目的是为了防止访问其他http时,由于超时导致自己的应用受影响。
4.5版本中,这两个参数的设置都抽象到了RequestConfig中,由相应的Builder构建,具体的例子如下:
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("得到的结果:" + response.getStatusLine());//得到请求结果
HttpEntity entity = response.getEntity();//得到请求回来的数据
String s = EntityUtils.toString(response.getEntity(), "UTF-8"); System.out.println(s);
setConnectTimeout:设置连接超时时间,单位毫秒。
setConnectionRequestTimeout:设置从connect Manager获取Connection 超时时间,单位毫秒。这个属性是新加的属性,因为目前版本是可以共享连接池的。
setSocketTimeout:请求获取数据的超时时间,单位毫秒。 如果访问一个接口,多少时间内无法返回数据,就直接放弃此次调用。
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一、连接超时:connectionTimeout
指的是连接一个url的连接等待时间。比如连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、读取数据超时:SocketTimeout
指的是连接上一个url,获取response的返回等待时间。
测试的时候连接url可以是本地开启的一个url,http://localhost:8080/firstTest.htm?method=test
当访问到这个链接时,线程sleep一段时间,来模拟返回response超时。
@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"; }
参考:
http://blog.csdn.net/hi_kevin/article/details/32316171