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微信小程序 auth.getAccessToken 获取access_token JAVA

一、认清auth.getAccessToken

这个接口不是wx.request()之类的在小程序端使用，它在服务器中编写代码使用，是一种请求规范。向微信服务器请求access_token时必须遵守的规范。即：(1)请求方式为GET （2）请求网址为https://api.weixin.qq.com/cgi-bin/token?（3）必须附带三个参数：grant_type，appid,secret.满足以上条件可以向服务器申请获得access_token，因而需要掌握网络请求相关的代码知识。

二、代码实现(JAVA为例)

(1)编写HttpRequest工具类

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package com.data.service;
 
import java.io.BufferedReader;
 
import java.io.IOException;
 
import java.io.InputStreamReader;
 
import java.io.OutputStreamWriter;
 
import java.io.PrintWriter;
 
import java.net.URL;
 
import java.net.URLConnection;
 
import java.util.List;
 
import java.util.Map;
public class HttpRequest {
       
     public  String sendGet(String url, String param) {
 
            String result = "";
 
            BufferedReader in = null;
 
            try {
 
                String urlNameString = url + "?" + param;
 
                URL realUrl = new URL(urlNameString);
 
                // 打开和URL之间的连接
 
                URLConnection connection = realUrl.openConnection();
 
                // 设置通用的请求属性
 
                connection.setRequestProperty("accept", "*/*");
 
                connection.setRequestProperty("connection", "Keep-Alive");
 
                connection.setRequestProperty("user-agent", "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");
 
                // 建立实际的连接
 
                connection.connect();
 
                // 获取所有响应头字段
 
                Map<String, List<String>> map = connection.getHeaderFields();
 
                // 遍历所有的响应头字段
 
                for (String key : map.keySet()) {
 
                    // System.out.println(key + "--->" + map.get(key));
 
                }
 
                // 定义 BufferedReader输入流来读取URL的响应
 
                in = new BufferedReader(new InputStreamReader(connection.getInputStream(), "utf-8"));
 
                // in = new BufferedReader(new
                // InputStreamReader(connection.getInputStream()));
 
                String line;
 
                while ((line = in.readLine()) != null) {
 
                    result += line;
 
                }
 
            } catch (Exception e) {
 
                System.out.println("发送GET请求出现异常！" + e);
 
                e.printStackTrace();
 
            }
 
            // 使用finally块来关闭输入流
 
            finally {
 
                try {
 
                    if (in != null) {
 
                        in.close();
 
                    }
 
                } catch (Exception e2) {
 
                    e2.printStackTrace();
 
                }
 
            }
 
            return result;
 
        }
}

　　(2调用工具类发起请求：

import com.data.service.HttpRequest;
import net.sf.json.JSONObject;
String APP_ID=request.getParameter("id");
String APPSECRET=request.getParameter("secret");
String grant_type="client_credential";
HttpRequest requestion=new HttpRequest();
String params = "grant_type=" + grant_type + "&secret=" + APPSECRET + "&appid="+ APP_ID; 
String sendGet = requestion.sendGet("https://api.weixin.qq.com/cgi-bin/token", params);
JSONObject json = JSONObject.fromObject(sendGet);
 String accesstoken = (String) json.get("access_token");
//accesstoken即为申请得到的access_token（这个值两小时就会失效  2022）