有时我们需要获取某个类对应的属性，实例方法，类方法等，下面就是个人做的简单总结:
导入：

#import <objc/message.h>

协议方法的获取

- (NSArray<NSString *> *)methodListWithProtocol:(Protocol *)protocol {
    unsigned int count = 0;
    NSMutableArray<NSString *> *methodList = @[].mutableCopy;
    struct objc_method_description *methods = protocol_copyMethodDescriptionList(protocol, YES, YES, &count);
    for (unsigned int i = 0; i < count; i++) {
        struct objc_method_description method = methods[i];
        NSString *name = NSStringFromSelector(method.name);
        [methodList addObject:name];
    }
    free(methods);
    return methodList;
}

类属性的获取

- (void)getIvarAndChange {
    NSLog(@"修改前:%@", self.name);
    unsigned int count = 0;
    Ivar *members = class_copyIvarList([self class], &count);
    for(int i = 0; i < count; i++) {
        Ivar ivar = members[i];
        const char *memberName = ivar_getName(ivar);
        const char *memberType = ivar_getTypeEncoding(ivar);
        //依次打印属性名称和属性类型
        NSLog(@"%s : %s", memberName, memberType);
        if(strcmp(memberName, "_name") == 0) {
            // 修改前
            NSString *name = (NSString *)object_getIvar(self, members[i]);
            NSLog(@"-name:%@", name);
            // 修改后
            object_setIvar(self, members[i], @"test");
            NSString *nameReset = (NSString *)object_getIvar(self, members[i]);
            NSLog(@"-nameReset:%@", nameReset);
            break;
        }
    }
    free(members);
    NSLog(@"修改后:%@", self.name);
}

实例方法的获取

- (void)getMethod {
    unsigned int count;
    Method *methods = class_copyMethodList([self class], &count);
    for (int i = 0; i < count; i++) {
        Method method = methods[i];
        SEL selector = method_getName(method);
        NSString *name = NSStringFromSelector(selector);
        NSLog(@"实例方法：%@",name);
    }
    free(methods);
}

类方法的获取

- (void)getClassMethod {
    Class metaClass = object_getClass([self class]);
    unsigned int count;
    Method *classMethods = class_copyMethodList(metaClass, &count);
    for (int i = 0; i < count; i++) {
        Method classMethod = classMethods[i];
        SEL selector = method_getName(classMethod);
        NSString *name = NSStringFromSelector(selector);
        NSLog(@"类方法：%@",name);
    }
    free(classMethods);
}

demo

参考资料：OC运行时
Objective-C 中的元类（meta class）是什么