在web开发中,我们经常需要模拟post及get请求,现在网上比较多的是使用httpclient3.x,然而httpclient4.x已经发布好几年了,而且4.x之后改名为HttpComponents,显然是今后的趋势.
Apache HttpComponents4.x中的HttpClient是一个很好的工具,它符合HTTP1.1规范，是基于HttpCore类包的实现。但是 HttpComponents4.x较之前httpclient3.x的API变化比较大,已经分为 HttpClient,HttpCore,HttpAsyncClient等多个组件,在模拟post及get请求时的编码也出现了较大的变化.

下面是httpclient4.3.4模拟get请求的例程

public void requestGet(String urlWithParams) throws Exception {          CloseableHttpClient httpclient = HttpClientBuilder.create().build();                     //HttpGet httpget = new HttpGet("http://www.baidu.com/");          HttpGet httpget = new HttpGet(urlWithParams);             //配置请求的超时设置          RequestConfig requestConfig = RequestConfig.custom()                    .setConnectionRequestTimeout(50)                  .setConnectTimeout(50)                    .setSocketTimeout(50).build();            httpget.setConfig(requestConfig);                      CloseableHttpResponse response = httpclient.execute(httpget);                  System.out.println("StatusCode -> " + response.getStatusLine().getStatusCode());                     HttpEntity entity = response.getEntity();                  String jsonStr = EntityUtils.toString(entity);//, "utf-8");          System.out.println(jsonStr);                     httpget.releaseConnection();  }

public void requestPost(String url,List<NameValuePair> params) throws ClientProtocolException, IOException {      CloseableHttpClient httpclient = HttpClientBuilder.create().build();                 HttpPost httppost = new HttpPost(url);          httppost.setEntity(new UrlEncodedFormEntity(params));                     CloseableHttpResponse response = httpclient.execute(httppost);          System.out.println(response.toString());                     HttpEntity entity = response.getEntity();          String jsonStr = EntityUtils.toString(entity, "utf-8");          System.out.println(jsonStr);                     httppost.releaseConnection();  }

public static void main(String[] args){      try {          String loginUrl = "http://localhost:8080/yours";          List<NameValuePair> params = new ArrayList<NameValuePair>();          params.add(new BasicNameValuePair("name", "zhang"));          params.add(new BasicNameValuePair("passwd", "123"));                         requestPost(loginUrl,params);      } catch (ClientProtocolException e) {          e.printStackTrace();      } catch (IOException e) {          e.printStackTrace();      }  }