java后台调用HttpURLConnection类模拟浏览器请求实例(可用于接口调用)

import java.io.BufferedReader;
import java.io.DataOutputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLEncoder;

public class HttpURLConnectionTest {
    public static final String GET_URL = "http://112.4.27.9/mall-back/if_user/store_list?storeId=32";
    public static final String POST_URL = "http://112.4.27.9/mall-back/if_user/store_list";
   
    /**
     * 接口调用 GET
     */
    public static void httpURLConectionGET() {
        try {
            URL url = new URL(GET_URL);    // 把字符串转换为URL请求地址
            HttpURLConnection connection = (HttpURLConnection) url.openConnection();// 打开连接
            connection.connect();// 连接会话
            // 获取输入流
            BufferedReader br = new BufferedReader(new InputStreamReader(connection.getInputStream()));
            String line;
            StringBuilder sb = new StringBuilder();
            while ((line = br.readLine()) != null) {// 循环读取流
                sb.append(line);
            }
            br.close();// 关闭流
            connection.disconnect();// 断开连接
            System.out.println(sb.toString());
        } catch (Exception e) {
            e.printStackTrace();
            System.out.println("失败!");
        }
    }
   
    /**
     * 接口调用  POST
     */
    public static void httpURLConnectionPOST () {
        try {
            URL url = new URL(POST_URL);
           
            // 将url 以 open方法返回的urlConnection  连接强转为HttpURLConnection连接  (标识一个url所引用的远程对象连接)
            HttpURLConnection connection = (HttpURLConnection) url.openConnection();// 此时cnnection只是为一个连接对象,待连接中
           
            // 设置连接输出流为true,默认false (post 请求是以流的方式隐式的传递参数)
            connection.setDoOutput(true);
           
            // 设置连接输入流为true
            connection.setDoInput(true);
           
            // 设置请求方式为post
            connection.setRequestMethod("POST");
           
            // post请求缓存设为false
            connection.setUseCaches(false);
           
            // 设置该HttpURLConnection实例是否自动执行重定向
            connection.setInstanceFollowRedirects(true);
           
            // 设置请求头里面的各个属性 (以下为设置内容的类型,设置为经过urlEncoded编码过的from参数)
            // application/x-javascript text/xml->xml数据 application/x-javascript->json对象 application/x-www-form-urlencoded->表单数据
            connection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
           
            // 建立连接 (请求未开始,直到connection.getInputStream()方法调用时才发起,以上各个参数设置需在此方法之前进行)
            connection.connect();
           
            // 创建输入输出流,用于往连接里面输出携带的参数,(输出内容为?后面的内容)
            DataOutputStream dataout = new DataOutputStream(connection.getOutputStream());
            String parm = "storeId=" + URLEncoder.encode("32", "utf-8"); //URLEncoder.encode()方法  为字符串进行编码
           
            // 将参数输出到连接
            dataout.writeBytes(parm);
           
            // 输出完成后刷新并关闭流
            dataout.flush();
            dataout.close(); // 重要且易忽略步骤 (关闭流,切记!)
           
            System.out.println(connection.getResponseCode());
           
            // 连接发起请求,处理服务器响应  (从连接获取到输入流并包装为bufferedReader)
            BufferedReader bf = new BufferedReader(new InputStreamReader(connection.getInputStream()));
            String line;
            StringBuilder sb = new StringBuilder(); // 用来存储响应数据
           
            // 循环读取流,若不到结尾处
            while ((line = bf.readLine()) != null) {
                sb.append(bf.readLine());
            }
            bf.close();    // 重要且易忽略步骤 (关闭流,切记!)
            connection.disconnect(); // 销毁连接
            System.out.println(sb.toString());
   
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
   
    public static void main(String[] args) {
//        httpURLConectionGET();
        httpURLConnectionPOST();
    }
}