项目要求：实现post请求，且请求格式是json格式。

maven依赖包


    org.apache.httpcomponents
    httpclient
    4.5.3
 
 
    commons-httpclient
    commons-httpclient
    3.1
  

java代码实现：

HttpClient httpClient = new HttpClient();
httpClient.getParams().setContentCharset("UTF-8");
PostMethod method = new PostMethod(url);
String str = "{\r\n" + 
    			"	\"beginDate\":\"2017-11-01\",\r\n" + 
    			"	\"endDate\":\"2017-11-01\"\r\n" + 
    			"}";
RequestEntity entity = new StringRequestEntity(str,"application/json","UTF-8");
method.setRequestEntity(entity);
httpClient.executeMethod(method);
InputStream in = method.getResponseBodyAsStream();
//下面将stream转换为String
StringBuffer sb = new StringBuffer();
InputStreamReader isr = new InputStreamReader(in, "UTF-8");
char[] b = new char[4096];
for(int n; (n = isr.read(b)) != -1;) {
    		sb.append(new String(b, 0, n));
    	}
 String returnStr = sb.toString();
 System.out.println(returnStr);