1.Class objc_getClass(const char *aClassName)

1> 傳入字符串類名

2> 返回對(duì)應(yīng)的類對(duì)象

2.Class object_getClass(id obj)

1> 傳入的obj可能是instance對(duì)象、class對(duì)象、meta-class對(duì)象

2> 返回值

a) 如果是instance對(duì)象，返回class對(duì)象

b) 如果是class對(duì)象，返回meta-class對(duì)象

c) 如果是meta-class對(duì)象，返回NSObject（基類）的meta-class對(duì)象

3.- (Class)class、+ (Class)class

1> 返回的就是類對(duì)象

- (Class)class {

    return self->isa;

}

+ (Class)class {

    return self;

}