小程序登录，通过code获取openId

小程序的登录，通过前端传过来code，在服务端（java）获取openId.

首先你得有appid以及secret(秘钥).

 

下面是业务逻辑代码（这里为了方便展示直接写在了controller）

@GetMapping("getCode")
public AjaxResult getCode(String code){
    // 授权（必填）
    String wxspAppid = "填写小程序appid";
    String wxspSecret = "填写小程序密钥";
    //默认是authorization_code
    String grant_type = "authorization_code";
    // 请求参数
    String params = "appid=" + wxspAppid + "&secret=" + wxspSecret + "&js_code=" + code + "&grant_type=" + grant_type;
    // 发送请求
    String sr = HttpRequest.sendPost("https://api.weixin.qq.com/sns/jscode2session", params);
    // 解析相应内容（转换成json对象）
    JSONObject json = JSONObject.parseObject(sr);
    logger.info("解析code请求结果:"+json.toString());
    // 获取会话密钥（session_key）
    //String session_key = json.getString("session_key");
    //获取openId
    String openid = json.getString("openid");
    return AjaxResult.success(openid);
}

JSONObject 引入的是alibaba的jar

import com.alibaba.fastjson.JSONObject;

 

       <!--      alibaba json 工具  -->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>fastjson</artifactId>
        </dependency>

 

HttpRequest工具类类

package com.ckf.common.core.utils; /** * @author serence * @date 2020/12/21 11:47 */ import com.alibaba.fastjson.JSONObject; import lombok.extern.slf4j.Slf4j; import java.io.*; import java.net.HttpURLConnection; import java.net.MalformedURLException; import java.net.URL; import java.net.URLConnection; import java.util.List; import java.util.Map; @Slf4j public class HttpRequest { /** * 向指定URL发送GET方法的请求 * * @param url * 发送请求的URL * @param param * 请求参数，请求参数应该是 name1=value1&name2=value2 的形式。 * @return URL 所代表远程资源的响应结果 */
    public static 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")); String line; while ((line = in.readLine()) != null) { result += line; } } catch (Exception e) { log.error("发送GET请求出现异常:"+e); } // 使用finally块来关闭输入流
        finally { try { if (in != null) { in.close(); } } catch (Exception e2) { e2.printStackTrace(); } } return result; } /** * 单参数数据访问 * */
    public static String sendGet(String url) { String result = ""; BufferedReader in = null; try { String urlNameString = url; 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")); 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; } /** * 向指定 URL 发送POST方法的请求 * * @param url * 发送请求的 URL * @param param * 请求参数，请求参数应该是 name1=value1&name2=value2 的形式。 * @return 所代表远程资源的响应结果 */
    public static String sendPost(String url, String param) { PrintWriter out = null; BufferedReader in = null; 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); // 获取URLConnection对象对应的输出流
            out = new PrintWriter(conn.getOutputStream()); // 发送请求参数
            out.print(param); // flush输出流的缓冲
            out.flush(); // 定义BufferedReader输入流来读取URL的响应
            in = new BufferedReader(new InputStreamReader(conn.getInputStream())); String line; while ((line = in.readLine()) != null) { result += line; } } 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 (in != null) { in.close(); } } catch (IOException ex) { ex.printStackTrace(); } } return result; } public static String doPost(String postUrl, JSONObject obj) { String lines = ""; StringBuffer sb = new StringBuffer(""); try { // 创建连接
            URL url = new URL(postUrl); HttpURLConnection connection = (HttpURLConnection) url.openConnection(); connection.setDoOutput(true); connection.setDoInput(true); connection.setRequestMethod("POST"); connection.setUseCaches(false); connection.setInstanceFollowRedirects(true); connection.setRequestProperty("Content-Type", "application/json"); connection.connect(); // POST请求
            DataOutputStream out = new DataOutputStream(connection.getOutputStream()); // out.writeChars(obj.toString()); // out.write(obj.toString().getBytes("UTF-8"));
            out.write(obj.toString().getBytes()); out.flush(); out.close(); // 读取响应
            BufferedReader reader = new BufferedReader(new InputStreamReader(connection.getInputStream(), "UTF-8")); while ((lines = reader.readLine()) != null) { lines = new String(lines.getBytes()); sb.append(lines); } System.out.println(sb); reader.close(); // 断开连接
 connection.disconnect(); } catch (MalformedURLException e) { // TODO Auto-generated catch block
 e.printStackTrace(); } catch (UnsupportedEncodingException e) { // TODO Auto-generated catch block
 e.printStackTrace(); } catch (IOException e) { // TODO Auto-generated catch block
 e.printStackTrace(); } return sb.toString(); } }

 

好了，有问题的小伙伴请留言哦！