angularjs如何处理多个异步请求的方法总结

$http.get('url1').success(function (d1) {
        $http.get('url2').success(function (d2) {
            //处理逻辑
        });
    });

var app = angular.module('app',[]);
app.controller('promiseControl',function($scope,$q,$http) {
    function getJson(url){
        var deferred = $q.defer();
        $http.get(url)
            .success(function(d){
                d = parseInt(d);
                console.log(d);
                deferred.resolve(d);
            });
        return deferred.promise;
    }
    getJson('json1.txt').then(function(){
        return getJson('json2.txt');
    }).then(function(){
        return getJson('json1.txt');
    }).then(function(){
        return getJson('json2.txt');
    }).then(function(d){
        console.log('end');
    });
});

var app = angular.module('app',[]);
app.controller('promiseControl',function($scope,$q,$http) {
    $q.all({first: $http.get('json1.txt'),second: $http.get('json2.txt')}).then(function(arr){
        console.log(arr);
        angular.forEach(arr,function(d){
            console.log(d);
            console.log(d.data);
        })
    });
});