AngularJS中.save和$save到资源的区别

我见过两者都调用的代码$save and save到角度的 $resource。

有什么区别以及什么时候使用？

最好的解释===例子 ：

// by writing '{ id: '@id' }' we want the id to be taken from 'id' parameter in request data, hence the '@' sign. Note that this mechanism is available for non-GET RQs only:
var Notes = $resource('/notes/:id', { id: '@id' });

var noteId = "my_note1";
// below we specify 'id' explicitly - has to be done for GET RQ:
// operations on our note are done inside callback function, just to make sure that the note is resolved:
var note = Notes.get({ id: noteId }, function () {

    // let's make some changes:
    note.topic = "A brand new topic here!";

    // save using $resource "static" action (aka "class" action). 'id' is taken from data object:
    Notes.save(note);
    // We can overwrite 'id' just like this: 
    Notes.save({ id: "some_other_noteId" }, note);

    // even more changes:
    note.body = "Blah blah blah, new boring body is here";

    // this time save using instance action. Again: 'id' is taken from data object:
    note.$save();
    // changing id with instance action? there you go:
    note.$save({ id: "yet_another_noteId" });

    // Naturally, we could just:
    note.id = "OMG_how_many_of_those_noteIds_has_he_left";
    Notes.save(note);
    // ... and with instance action:
    note.id = "OK_he_wins";
    note.$save();
});

甚至定制$resource行动（由您定义）有其$- 带前缀的对应项，只要它们不是 GET - 请参阅http://docs.angularjs.org/api/ngResource.$resource#example_creating-a-custom-put-request http://docs.angularjs.org/api/ngResource.%24resource#example_creating-a-custom-put-request.
不，并非所有操作都有实例方法版本。调用的意义是什么GET在一个实例上？来自官方ngResource docs:

可以使用以下参数调用类对象或实例对象上的操作方法：

• HTTP GET“类”操作：Resource.action([参数], [成功], [错误])
• 非 GET“类”操作：Resource.action([参数], postData, [成功], [错误])
• 非 GET 实例操作：instance.$action([参数], [成功], [错误])