微信小程序开发之异步转同步

App({
  onLaunch: function(){

  },
  getToken: function(){
    let _this = this;
    return new Promise(function(resolve, reject){
      wx.checkSession({
        success: function (res) { resolve(res); },
        fail: function (res) {
          wx.login({
            success: res => {
              // 发送 res.code 到后台换取 openId, sessionKey, unionId
              if (res.code) {
                wx.request({
                  url: CONFIG.loginUrl,
                  data: {
                    code: res.code
                  },
                  header: {
                    'shopId': CONFIG.shopId
                  },
                  method: 'POST',
                  success: res => {
                    wx.setStorageSync('token', res.data);  //储存返回的token
                    resolve(res);
                  }
                })
              } else {
                console.log('获取用户登录态失败！' + res.errMsg);
                reject('error');
              }
            }
          })
        }
      })
    })
  }
})

const app = getApp();
Page({
  onLoad: function(){
    let token = wx.getStorageSync('token');
    if (token == ''){
      //第一次登录，获取登录状态
      app.getToken().then(function (res) {
        _this.getData();   //此时token必然已经获取到，且getData()在此时才会执行
      })
    }else{
      //有token的情况直接获取数据
      _this.getData();
    }
  },
  //获取数据
  getData: function(){
    wx.request({
      header: {
        'token': wx.getStorageSync('token')
      },
      url: 'https://xxxxx.xxxxx',
      method: 'GET',
      success: res => {
        console.log(res);
      }
    })
  }
})

//封装wx.request() 
function request(requestMapping, data, requestWay, contentType) {
  wx.showLoading({
    title: '请稍后',
  })
  return new Promise(function(resolve, reject) {
    console.log('请求中。。。。。')
    wx.request({
      url: '自己的服务器地址' + requestMapping,
      data: data,
      header: {
        'content-type': contentType // 默认值
      },
      timeout: 3000,
      method: requestWay,
      success(res) {
        //console.log(res)
        if (res.data.success == false || res.data.statusCode == 404) {
          reject(res)
        } else {
          resolve(res)
        }
      },
      fail: (e) => {  
        wx.showToast({
          title: '连接失败',
          icon: 'none'
        })},
      complete: () => {
        wx.hideLoading()
      }
    })
  })
}

//获取openid
function getOpenId(app, that){
  return new Promise(function (resolve, reject) {
        wx.login({
          success: function (yes) {
            // 发送 res.code 到后台换取 openId, sessionKey, unionId
            var requestMapping = '/testopenid'
            var data = {
              code: yes.code
            }
            var requestWay = 'GET'
            var contentType = 'application/json'
            var p =request(requestMapping, data, requestWay, contentType)
            p.then(res => {
              //console.log(res) 做一些后续操作
              app.globalData.openId = res.data;
                    resolve(res)
            }).catch(e => {
              reject(e)  
            })
          },
          fail(e) {
            console.log(e)
          }
        })  
  })
}

 @RequestMapping("/testopenid")
    public String getUserInfo(@RequestParam(name = "code") String code) throws Exception {
        System.out.println("code" + code);
        String url = "https://api.weixin.qq.com/sns/jscode2session";
        url += "?appid=xxxxxxxxxxxxx";//自己的appid
        url += "&secret=xxxxxxxxxxxxxxxxxxx";//自己的appSecret
        url += "&js_code=" + code;
        url += "&grant_type=authorization_code";
        url += "&connect_redirect=1";
        String res = null;
        CloseableHttpClient httpClient = HttpClientBuilder.create().build();
        // DefaultHttpClient();
        HttpGet httpget = new HttpGet(url);    //GET方式
        CloseableHttpResponse response = null;
        // 配置信息
        RequestConfig requestConfig = RequestConfig.custom()          // 设置连接超时时间(单位毫秒)
                .setConnectTimeout(5000)                    // 设置请求超时时间(单位毫秒)
                .setConnectionRequestTimeout(5000)             // socket读写超时时间(单位毫秒)
                .setSocketTimeout(5000)                    // 设置是否允许重定向(默认为true)
                .setRedirectsEnabled(false).build();           // 将上面的配置信息 运用到这个Get请求里
        httpget.setConfig(requestConfig);                         // 由客户端执行(发送)Get请求
        response = httpClient.execute(httpget);                   // 从响应模型中获取响应实体
        HttpEntity responseEntity = response.getEntity();
        System.out.println("响应状态为:" + response.getStatusLine());
        if (responseEntity != null) {
            res = EntityUtils.toString(responseEntity);
            System.out.println("响应内容长度为:" + responseEntity.getContentLength());
            System.out.println("响应内容为:" + res);
        }
        // 释放资源
        if (httpClient != null) {
            httpClient.close();
        }
        if (response != null) {
            response.close();
        }
        JSONObject jo = JSON.parseObject(res);
        String openid = jo.getString("openid");
        System.out.println("openid" + openid);
        return openid;
    }