微信小程序授权登录，前后端代码，Java版本，并获取手机号、昵称和头像

前端代码：

1. 在页面中引入微信登录组件：

<login wx:if="{{!isLogin}}" bind:success="onLoginSuccess" bind:fail="onLoginFail"></login>

2. 在页面中定义微信登录组件的回调函数：

onLoginSuccess(event) {
  const { code } = event.detail;
  wx.request({
    url: 'https://your-backend-server.com/wechat/login',
    method: 'POST',
    data: {
      code: code,
    },
    success: res => {
      const { token } = res.data;
      wx.setStorageSync('token', token);
      this.setData({
        isLogin: true,
      });
    },
  });
},
onLoginFail() {
  wx.showToast({
    title: '登录失败，请重试',
    icon: 'none',
  });
},

3. 在页面中调用微信提供的获取用户信息的接口：

wx.getUserInfo({
  success: res => {
    const { encryptedData, iv } = res;
    wx.request({
      url: 'https://your-backend-server.com/wechat/user-info',
      method: 'POST',
      header: {
        Authorization: `Bearer ${wx.getStorageSync('token')}`,
      },
      data: {
        encryptedData: encryptedData,
        iv: iv,
      },
      success: res => {
        const { nickName, avatarUrl } = res.data;
        this.setData({
          nickName: nickName,
          avatarUrl: avatarUrl,
        });
      },
    });
  },
});

后端代码：

1. 在后端中实现微信登录的接口：

@PostMapping("/wechat/login")
public ResponseEntity<Object> login(@RequestParam String code) {
  String appId = "your-app-id";
  String appSecret = "your-app-secret";
  String url = "https://api.weixin.qq.com/sns/jscode2session?" +
      "appid=" + appId +
      "&secret=" + appSecret +
      "&js_code=" + code +
      "&grant_type=authorization_code";
  RestTemplate restTemplate = new RestTemplate();
  String response = restTemplate.getForObject(url, String.class);
  ObjectMapper objectMapper = new ObjectMapper();
  try {
    JsonNode jsonNode = objectMapper.readTree(response);
    if (jsonNode.has("openid")) {
      String openid = jsonNode.get("openid").asText();
      String sessionKey = jsonNode.get("session_key").asText();
      String token = jwtService.generateToken(openid, sessionKey);
      return ResponseEntity.ok(Map.of("token", token));
    }
  } catch (JsonProcessingException e) {
    e.printStackTrace();
  }
  return ResponseEntity.badRequest().build();
}

2. 在后端中实现获取微信用户信息的接口：

@PostMapping("/wechat/user-info")
public ResponseEntity<Object> getUserInfo(@RequestHeader("Authorization") String authorization,
    @RequestParam String encryptedData, @RequestParam String iv) {
  String sessionKey = jwtService.getSessionKey(authorization);
  byte[] sessionKeyBytes = Base64.getDecoder().decode(sessionKey);
  byte[] encryptedDataBytes = Base64.getDecoder().decode(encryptedData);
  byte[] ivBytes = Base64.getDecoder().decode(iv);
  try {
    Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
    SecretKeySpec secretKeySpec = new SecretKeySpec(sessionKeyBytes, "AES");
    IvParameterSpec ivParameterSpec = new IvParameterSpec(ivBytes);
    cipher.init(Cipher.DECRYPT_MODE, secretKeySpec, ivParameterSpec);
    byte[] decryptedDataBytes = cipher.doFinal(encryptedDataBytes);
    String decryptedDataString = new String(decryptedDataBytes, StandardCharsets.UTF_8);
    ObjectMapper objectMapper = new ObjectMapper();
    JsonNode jsonNode = objectMapper.readTree(decryptedDataString);
    if (jsonNode.has("nickName") && jsonNode.has("avatarUrl")) {
      String nickName = jsonNode.get("nickName").asText();
      String avatarUrl = jsonNode.get("avatarUrl").asText();
      return ResponseEntity.ok(Map.of("nickName", nickName, "avatarUrl", avatarUrl));
    }
  } catch (NoSuchAlgorithmException | NoSuchPaddingException | InvalidKeyException | InvalidAlgorithmParameterException | IllegalBlockSizeException | BadPaddingException | JsonProcessingException e) {
    e.printStackTrace();
  }
  return ResponseEntity.badRequest().build();
}

3. 在后端中实现JWT的生成和解析：

@Service
public class JwtService {
  private final String secret = "your-jwt-secret";
  private final long expirationTime = 86400000L;

  public String generateToken(String openid, String sessionKey) {
    Date now = new Date();
    Date expirationDate = new Date(now.getTime() + expirationTime);
    return Jwts.builder()
        .setSubject(openid)
        .claim("session_key", sessionKey)
        .setIssuedAt(now)
        .setExpiration(expirationDate)
        .signWith(SignatureAlgorithm.HS512, secret)
        .compact();
  }

  public String getSessionKey(String authorization) {
    String token = authorization.replace("Bearer ", "");
    String sessionKey = Jwts.parser().setSigningKey(secret).parseClaimsJws(token).getBody().get("session_key", String.class);
    return sessionKey;
  }
}