java模拟post请求发送json数据

import com.alibaba.fastjson.JSONObject;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.ContentType;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.util.EntityUtils;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.net.HttpURLConnection;
import java.net.URL;


public class HttpRequest2 {
      public static String sendPost(String url,String param){
          OutputStreamWriter out =null;
          BufferedReader reader = null;
          String response = "";

          //创建连接
          try {
              URL httpUrl = null; //HTTP URL类 用这个类来创建连接
              //创建URL
              httpUrl = new URL(url);
              //建立连接
              HttpURLConnection conn = (HttpURLConnection) httpUrl.openConnection();
              conn.setRequestMethod("POST");
              conn.setRequestProperty("Content-Type", "application/json");
              conn.setRequestProperty("connection", "keep-alive");
              conn.setUseCaches(false);//设置不要缓存
              conn.setInstanceFollowRedirects(true);
              conn.setDoOutput(true);
              conn.setDoInput(true);
              conn.connect();
              //POST请求
              out = new OutputStreamWriter(
                      conn.getOutputStream());
              out.write(param);
              out.flush();
              //读取响应
              reader = new BufferedReader(new InputStreamReader(
                      conn.getInputStream()));
              String lines;
              while ((lines = reader.readLine()) != null) {
                  lines = new String(lines.getBytes(), "utf-8");
                  response+=lines;
              }
              reader.close();
              // 断开连接
              conn.disconnect();

          } catch (Exception e) {
              System.out.println("发送 POST 请求出现异常！"+e);
              e.printStackTrace();
          }
          //使用finally块来关闭输出流、输入流
          finally{
              try{
                  if(out!=null){
                      out.close();
                  }
                  if(reader!=null){
                      reader.close();
                  }
              }
              catch(IOException ex){
                  ex.printStackTrace();
              }
          }

          return response;
      }


    public static String sendPost2(String url, String data) {
        String response = null;

        try {
            CloseableHttpClient httpclient = null;
            CloseableHttpResponse httpresponse = null;
            try {
                httpclient = HttpClients.createDefault();
                HttpPost httppost = new HttpPost(url);
                StringEntity stringentity = new StringEntity(data,
                        ContentType.create("text/json", "UTF-8"));
                httppost.setEntity(stringentity);
                httpresponse = httpclient.execute(httppost);
                response = EntityUtils
                        .toString(httpresponse.getEntity());

            } finally {
                if (httpclient != null) {
                    httpclient.close();
                }
                if (httpresponse != null) {
                    httpresponse.close();
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        return response;
    }

    public static void main(String[] args) {
        JSONObject jsonParam = new JSONObject();
        jsonParam.put("id", "12306");
        jsonParam.put("name", "zhangsan");
        String param = jsonParam.toJSONString();

        String url="http://localhost:8080/demo/one";

        String sendPost = sendPost2(url, param);
        System.out.println(sendPost);

    }

}

下面是后台的代码

@RestController
@RequestMapping("/demo")
public class PostController {

    @Resource
    protected HttpServletRequest request;

    @RequestMapping(value = "/one",method = RequestMethod.POST)
    public String getResult(String str)throws Exception{

        InputStreamReader reader = new InputStreamReader(request.getInputStream(),"UTF-8");
        char[] buff = new char[1024];
        int length =0;
        while((length =reader.read(buff))!=-1){
            String message = new String(buff,0,length);
            System.out.println("接收到的信息   "+ message);
        }

        return JSON.toJSONString("这是post请求");
    }
}

 依赖的jar包

 <!--http 请求需要的jar包-->
        <dependency>
            <groupId>org.apache.httpcomponents</groupId>
            <artifactId>httpcore</artifactId>
            <version>4.4.10</version>
        </dependency>
        <dependency>
            <groupId>org.apache.httpcomponents</groupId>
            <artifactId>httpclient</artifactId>
            <version>4.5.6</version>
        </dependency>