httpClient创建对象、设置超时

从老版本和新版本进行比较说明：

1.创建HttpClient对象

3.X：

HttpClient httpClient = new DefaultHttpClient();

4.3:

CloseableHttpClient httpClient = HttpClients.createDefault();

2.超时设置:

3.X:

HttpClient httpClient = new HttpClient();
client.setConnectionTimeout(30000); 
client.setTimeout(30000);

或者：

HttpClient httpClient= new HttpClient(); 
httpClient.getHttpConnectionManager().getParams().setConnectionTimeout(5000);

4.X(4.3后已过时)：

HttpClient httpClient=new DefaultHttpClient();
httpClient.getParams().setParameter(CoreConnectionPNames.CONNECTION_TIMEOUT,2000);//连接时间
httpClient.getParams().setParameter(CoreConnectionPNames.SO_TIMEOUT,2000);    //数据传输时间

4.3：

CloseableHttpClient httpClient = HttpClients.createDefault();
HttpPost httpPost=new HttpPost("http://www.baidu.com");    //HTTP post请求
// 请求获取数据的超时时间 、 设置从connect Manager获取Connection超时时间、设置连接超时时间
RequestConfig requestConfig = RequestConfig.custom().setSocketTimeout(10000).setConnectionRequestTimeout(3000).setConnectTimeout(10000).build();
httpPost.setConfig(requestConfig);

3.httpclient 4.3.1，当不设置 超时时间的时候

　　如果请求的url是通的，但服务器没有响应，会一直等待响应；
　　如果请求的url是不通的，21秒后会报：Connection timed out: connect