1、调用Tao.login(),获取临时code，将获取到的 code 发送给后台换取用户唯一标识OpenID和会话密钥 sessionKey

app.ts

import { createApp } from 'vue'
import './app.scss'
import 'taro-ui-vue3/dist/style/index.scss' 
import Taro from '@tarojs/taro'
import globalData from './common/globalData'

var baseUrl = 'http://localhost:8080/'
const App = createApp({
  onLaunch: function() {
    //调用 wx.login(),获取临时 code
    Taro.login({  
      success: function (res) {  
          if (res.code) {
              //将获取到的 code 发送给后台换取用户唯一标识OpenID和会话密钥 sessionKey
              Taro.request({
                url: baseUrl + 'app/code2seesion',
                method: "POST",
                data: {
                  code: res.code
                },
                success: function (res2) {
                  globalData.sessionKey = res2.data.sessionKey
                  globalData.openid = res2.data.openid
                }
              })
          } else {  
              console.log('获取用户登录态失败！' + res.errMsg)  
          }  
      }  
  });  

  }
})

export default App

java后台：

@RestController
@RequestMapping("/app")
public class MiniController {
    @Autowired
    private RestTemplate restTemplate;

    @PostMapping("/code2seesion")
    public Result code2seesion(@RequestBody Map<String,Object> params) {
        // code取得
        String code = params.get("code").toString();
        Map<String, String> requestMap = new HashMap<>();
        requestMap.put("appid", "XXXXXXX");
        requestMap.put("secret", "SSSSSSS");
        requestMap.put("code", code);

        String url = String.format("https://api.weixin.qq.com/sns/jscode2session?appid=%s&secret=%s&js_code=%s&grant_type=%s", "XXXXXXX", "SSSSSSS", code, "authorization_code");
        ResponseEntity<String> responseEntity = restTemplate.getForEntity(url, String.class,requestMap);
        JSONObject jsonObject=JSONObject.parseObject(responseEntity.getBody());
        String openId=jsonObject.getString("openid");
        String session_key=jsonObject.getString("session_key");
        return Result.OK(new HashMap(){{
            put("sessionKey", session_key);
            put("openid", openId);
        }});
    }

2、页面使用getPhoneNumber获取信息，传到后台解析手机号

index.vue

    <view class="other-login-type-text">其他登录方式</view>
    <view>
      <button open-type="getPhoneNumber" @getphonenumber="getPhoneNumber"> 
         <image src="../../images/weixin.jpg" class="weixin-image"></image>
      </button>
    </view>


   //使用微信方式登录
    getPhoneNumber(e) {
      if (e.detail.errMsg == "getPhoneNumber:ok") {
        let params = {
          encryptedData: e.detail.encryptedData,
          iv: e.detail.iv,
          sessionKey: globalData.sessionKey,
        }
        //解析加密的用户信息
        commonUtil.requestPost("app/decodePhone", params, function success(res){
          if(res.code == "0000") {
            globalData.driverPhone = res.phone;
            //登录成功，跳转到首页
            Taro.reLaunch({
              url: "../home/home",
            });
          }
        })
      }
    },

java后台：

    @PostMapping("/decodePhone")
    public Result decodePhone(@RequestBody Map<String,Object> params) {
        String encryptedData = params.get("encryptedData").toString();
        String iv = params.get("iv").toString();
        String sessionKey = params.get("sessionKey").toString();
        // 解析电话号码
        String mobile = this.decodePhone(encryptedData, iv, sessionKey);
        if (mobile == null) {
            return Result.error("解析电话号码失败！");
        }
        return Result.OK(new HashMap(){{
            put("phone", mobile);
        }});
    }


    public String decodePhone(String encryptedData, String iv, String sessionKey) {
        // 被加密的数据
        byte[] encryptedDataByte = org.bouncycastle.util.encoders.Base64.decode(encryptedData);
        // 加密秘钥
        byte[] sessionKeyByte = org.bouncycastle.util.encoders.Base64.decode(sessionKey);
        // 偏移量
        byte[] ivByte = org.bouncycastle.util.encoders.Base64.decode(iv);

        try {
            // 如果密钥不足16位，那么就补足.  这个if 中的内容很重要
            int base = 16;
            if (sessionKeyByte.length % base != 0) {
                int groups = sessionKeyByte.length / base + (sessionKeyByte.length % base != 0 ? 1 : 0);
                byte[] temp = new byte[groups * base];
                Arrays.fill(temp, (byte) 0);
                System.arraycopy(sessionKeyByte, 0, temp, 0, sessionKeyByte.length);
                sessionKeyByte = temp;
            }
            // 初始化
            Security.addProvider(new BouncyCastleProvider());
            Cipher cipher = Cipher.getInstance("AES/CBC/PKCS7Padding");
            SecretKeySpec spec = new SecretKeySpec(sessionKeyByte, "AES");
            AlgorithmParameters parameters = AlgorithmParameters.getInstance("AES");
            parameters.init(new IvParameterSpec(ivByte));
            cipher.init(Cipher.DECRYPT_MODE, spec, parameters);// 初始化
            byte[] resultByte = cipher.doFinal(encryptedDataByte);
            if (null != resultByte && resultByte.length > 0) {
                String result = new String(resultByte, "UTF-8");
                return JSONObject.parseObject(result).getString("phoneNumber");
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }