微信小程序加后端源码大全

### 微信小程序与后端集成的完整源码示例

#### Laravel 实现微信小程序用户登录功能
为了实现微信小程序用户的登录验证，可以采用基于Laravel框架的服务端逻辑。此过程涉及获取前端传来的临时登录凭证code并将其发送给微信服务器以换取session_key和openid[^1]。

// app/Http/Controllers/WXLoginController.php
public function login(Request $request){
    $code = $request->input('code');
    
    // 调用微信接口获得 session_key 和 openid
    $url = "https://api.weixin.qq.com/sns/jscode2session?appid=APPID&secret=SECRET&js_code=$code&grant_type=authorization_code";
    $response = file_get_contents($url);
    $data = json_decode($response, true);

    if(isset($data['errcode'])){
        return response()->json(['error' => 'Invalid code'], 400);
    }

    Session::put('open_id', $data['openid']);
    Session::save();

    return response()->json([
        'success' => true,
        'message' => 'Logged In',
        'user_openid'=> $data['openid']
    ]);
}

#### 使用Python作为后端服务支持微信小程序
对于希望利用Python构建的小程序后台应用而言，Flask或Django都是不错的选择。这里给出一段简单的Flask应用程序片段用于处理来自微信小程序的数据请求[^3]。

from flask import Flask, request, jsonify
import pymysql.cursors

app = Flask(__name__)

@app.route('/login', methods=['POST'])
def login():
    data = request.get_json()
    wx_code = data.get('code')

    # 假设已经完成了与微信API交互得到openid的过程...
    open_id = get_openid_from_wechat_api(wx_code)

    connection = pymysql.connect(
        host='localhost',
        user='root',
        password='',
        db='wechat_mini_program_db'
    )

    try:
        with connection.cursor() as cursor:
            sql = "INSERT INTO `users` (`wx_openid`) VALUES (%s)"
            cursor.execute(sql, (open_id,))
        
        connection.commit()

        return jsonify({
            'status': 'ok',
            'msg': f'Successfully registered new user {open_id}'
        })
    finally:
        connection.close()

#### Java Servlet 连接MySQL数据库实例
当选用Java技术栈时，则可以通过创建Servlet来接收从前端发过来的信息，并进一步操作存储于关系型数据库中的数据记录。下面展示了一个基本的例子说明如何完成这项任务[^2]。

@WebServlet("/register")
public class RegisterServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;

    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        String username = req.getParameter("username");
        String pwd = req.getParameter("password");

        Connection conn;
        PreparedStatement pst;
        ResultSet rs;

        try{
            Class.forName("com.mysql.jdbc.Driver").newInstance();
            conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/wechat", "root", "");

            String query = "SELECT * FROM users WHERE name=?";
            pst = conn.prepareStatement(query);
            pst.setString(1, username);
            rs = pst.executeQuery();

            if(!rs.next()){
                // 用户不存在则注册新账户
                String insertQuery = "INSERT INTO users(name,password)VALUES (?,?)";
                pst = conn.prepareStatement(insertQuery);
                pst.setString(1, username);
                pst.setString(2, pwd);
                
                int result = pst.executeUpdate();
                System.out.println(result+" row(s) affected.");
            }else{
                out.print("User already exists!");
            }
            
            pst.close();
            conn.close();
        }catch(Exception e){e.printStackTrace();}
    }
}