java实现向服务端发送GET和POST请求

 
package com.hongyuan.test;
  
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.HttpURLConnection;
import java.net.URL;
  
public class HttpClient {
    //发送一个GET请求
    public static String get(String path) throws Exception{
        HttpURLConnection httpConn=null;
        BufferedReader in=null;
        try {
            URL url=new URL(path);
            httpConn=(HttpURLConnection)url.openConnection();
              
            //读取响应
            if(httpConn.getResponseCode()==HttpURLConnection.HTTP_OK){
                StringBuffer content=new StringBuffer();
                String tempStr="";
                in=new BufferedReader(new InputStreamReader(httpConn.getInputStream()));
                while((tempStr=in.readLine())!=null){
                    content.append(tempStr);
                }
                return content.toString();
            }else{
                throw new Exception("请求出现了问题!");
            }
        } catch (IOException e) {
            e.printStackTrace();
        }finally{
            in.close();
            httpConn.disconnect();
        }
        return null;
    }
    //发送一个GET请求,参数形式key1=value1&key2=value2...
    public static String post(String path,String params) throws Exception{
        HttpURLConnection httpConn=null;
        BufferedReader in=null;
        PrintWriter out=null;
        try {
            URL url=new URL(path);
            httpConn=(HttpURLConnection)url.openConnection();
            httpConn.setRequestMethod("POST");
            httpConn.setDoInput(true);
            httpConn.setDoOutput(true);
              
            //发送post请求参数
            out=new PrintWriter(httpConn.getOutputStream());
            out.println(params);
            out.flush();
              
            //读取响应
            if(httpConn.getResponseCode()==HttpURLConnection.HTTP_OK){
                StringBuffer content=new StringBuffer();
                String tempStr="";
                in=new BufferedReader(new InputStreamReader(httpConn.getInputStream()));
                while((tempStr=in.readLine())!=null){
                    content.append(tempStr);
                }
                return content.toString();
            }else{
                throw new Exception("请求出现了问题!");
            }
        } catch (IOException e) {
            e.printStackTrace();
        }finally{
            in.close();
            out.close();
            httpConn.disconnect();
        }
        return null;
    }
      
    public static void main(String[] args) throws Exception {
        //String resMessage=HttpClient.get("http://localhost:3000/hello?hello=hello get");
        String resMessage=HttpClient.post("http://localhost:3000/hello","hello=hello post");
        System.out.println(resMessage);
    }
  
}