var list = [];//大的集合
$.each(that.categoryList, function(index,value){
   $.ajax({
       type: 'get',
       url: that.getHotUrl,
       data:{
           category:value.id,
           pageIndex:1,
           pageSize:2,
           token:token
       },
       dataType: 'json',
       success: function(response){
          if(response.code==200){
              var obj = new Object();  //集合对象
              obj.category_name=value.name;
              obj.items = response.data.items;
              console.log(obj);
              list.push(obj);
          }
      },
      error: function(err) {
           console.log(err);
     }
  });
});
console.log(list);

循环调用接口拿到数据构建一个对象数组，console结果list为空，但obj都正确