Java实现向Web站点发送GET/POST请求

如何用Java实现本地调用远程接口并获取数据？本文章将告诉你答案。

废话不多说，直接撸代码。

package com.future.net;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.URL;
import java.net.URLConnection;
import java.nio.charset.Charset;
import java.util.List;
import java.util.Map;


public class GetPostTest {


    /** @Description: GET请求方法
     * @Author:future
     * @Date:2020/5/31/17:27 
     * @Param 
     * @return java.lang.String
     */
    public static String sendGet(String url,String param){
        String result = "";
        String urlName = url+"?"+param;

        try {
            URL realUrl = new URL(urlName);
            // 打开和URL之间的连接
            URLConnection conn = realUrl.openConnection();
            // 设置通用的请求属性
            conn.setRequestProperty("accept","*/*" );
            conn.setRequestProperty("connection","Keep-Alive" );
            conn.setRequestProperty("user-agent","Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1)" );
            // 获取实际的连接
            conn.connect();
            Map<String ,List<String>> map = conn.getHeaderFields();
            for (Map.Entry<String ,List<String >> m:map.entrySet()){
                System.out.println("key:"+m.getKey()+",value:"+m.getValue());
            }

            // 定义BufferedReader输入流来读取URL的响应
            BufferedReader in = new BufferedReader(new InputStreamReader(conn.getInputStream(),"utf-8"));
            String line;

            while ((line=in.readLine())!= null){
                result  += "\n"+line;
            }

        }catch (Exception e){
            
        }
        return result;
    }

    /** @Description:POST请求方法
     * @Author:future
     * @Date:2020/5/31/19:56
     * @Param
     * @return java.lang.String
     */
    public static String sendPost(String url,String param){
        String result = "";
        try {
            URL realUrl = new URL(url);
            // 打开和URL之间的连接
            URLConnection conn = realUrl.openConnection();
            // 设置通用的请求属性
            conn.setRequestProperty("accept","*/*" );
            conn.setRequestProperty("connection","Keep-Alive" );
            conn.setRequestProperty("user-agent","Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1)" );
            // 发送POST请求必须设置如下两行
            conn.setDoOutput(true);
            conn.setDoInput(true);
            PrintWriter out = new PrintWriter(conn.getOutputStream());
            out.print(param);
            out.flush();
            Map<String ,List<String>> map = conn.getHeaderFields();
            for (Map.Entry<String ,List<String >> m:map.entrySet()){
                System.out.println("key:"+m.getKey()+",value:"+m.getValue());
            }

            // 定义BufferedReader输入流来读取URL的响应
            BufferedReader in = new BufferedReader(new InputStreamReader(conn.getInputStream(),"utf-8"));
            String line;

            while ((line=in.readLine())!= null){
                result  += "\n"+line;
            }

        }catch (Exception e){
            System.out.println("发送POST请求出现异常:"+e.getMessage());
            e.printStackTrace();
        }
        return result;
    }
}

测试：

public class GetPostTest {
 public static void main(String args[]){
        // 大家注意，这里测试的地址都是我本地项目的请求地址
        //(记得换成自己的地址或者网上可以访问的地址)
        String url2 = "http://localhost:8080/xxx/getProductList?page=1&limit=10";
        String s = GetPostTest.sendGet(url,null);
        System.out.println(s);
        System.out.println("==========");
        String post_url = "http://localhost:8080/xxx/updateUser";
        String param = "userId=1&userName=admin&description=test&pwd=666666";

        String result = GetPostTest.sendPost(post_url,param );
        System.out.println(new String(result.getBytes(), Charset.forName("UTF-8")));;
    }
}

测试结果：

完毕！！