在app.js中添加如下两个方法即可：

// 设置需要回调的地址
    setCallbackUrl: function(mode) {
        return new Promise((resolve,reject) => {
            let pages = getCurrentPages(); //获取加载的页面
            let currentPage = pages[pages.length - 1]; //获取当前页面的对象
            let urlPage = ''; // 存储的跳转地址
            let url = currentPage.route; //当前页面url
            let argumentsStr = '';
            let options = currentPage.options; //如果要获取url中所带的参数可以查看options
            for (let key in options) {
                    let value = options[key];
                    argumentsStr += key + '=' + value + '&';
            }
            if(argumentsStr) {
                 argumentsStr = argumentsStr.substring(0, argumentsStr.length - 1);
                 urlPage = url + '?' + argumentsStr;
            } else {
                urlPage = url;
            }
            let callbackObj = {
                callbackUrl: `/${urlPage}`,
                mode: mode || 'redirectTo'
            }
             wx.setStorageSync('callbackObj', JSON.stringify(callbackObj));
             resolve();
        })
    },
    
    // 获取本地可以回调的地址
    getCallBackUrl: function() {
        return new Promise((resolve,reject) => {
            const callbackObj = wx.getStorageSync('callbackObj');
            if(callbackObj) {
                let resultObj = JSON.parse(callbackObj);
                let callbackUrl = resultObj.callbackUrl;
                let mode = resultObj.mode;
                mode == 'redirectTo' && wx.redirectTo({url: callbackUrl});
                mode == 'switchTab' && wx.switchTab({url: callbackUrl});
                mode == 'reLaunch' && wx.reLaunch({url: callbackUrl});
                mode == 'navigateTo' && wx.navigateTo({url: callbackUrl});
            } else {
                reject();
            }
        })
    },

跳转到登录页面前通过setCallbackUrl方法获取即将跳转的当前页面，当登录后调用getCallBackUrl方法，查看本地是否有需要跳转的地址，没有就在catch中执行登录后的正常逻辑，比如跳转到我的模块页面。代码如下:

app.getCallBackUrl().catch(() => {
    // catch中执行默认的操作
    wx.redirectTo({
        url: '/pages/my/mycenter/mycenter'
    })
})