Category分类

Student.h:

#import <Foundation/Foundation.h>

@interface Student : NSObject

@property(nonatomic) int no;
-(void)TestStudent;
@end

Student.m:

#import "Student.h"

@implementation Student
-(void)TestStudent{
    NSLog(@"我是测试Student的方法");
}
@end

Student+Test.h

#import "Student.h"
//()分类文件方法
//Test是分类的方法名
@interface Student (Test)
//注意：只能扩展方法，不能添加成员变量
-(void) Test2;
@end
@interface Student(Addtion)
-(void) Test3;
@end

Student+Test.m:

#import "Student+Test.h"

@implementation Student (Test)
-(void)Test2
{
    NSLog(@"我是分类方法Test2");
}
@end
@implementation Student(Addtion)
-(void)Test3{
    NSLog(@"我是分类方法test3");
}
@end

NSString+JSON.h:

#import <Foundation/Foundation.h>

@interface NSString (JSON)
+(NSString *)json;
@end

NSString+JSON.m:

#import "NSString+JSON.h"

@implementation NSString (JSON)
+(NSString *)json{
    return @"{'name':'dxw','id':10}";
}
@end

main:

#import <Foundation/Foundation.h>
#import "Student.h"
#import "Student+Test.h"
#import "NSString+JSON.h"

int main(int argc, const char * argv[])
{

    @autoreleasepool {
        
        Student *stu=[[[Student alloc] init] autorelease];
        [stu TestStudent];
        [stu Test2];
        [stu Test3];
        NSLog(@"%@",[NSString json]);
    }
    return 0;
}

结果：

2013-08-02 15:47:57.364 Category[1322:303] 我是测试Student的方法

2013-08-02 15:47:57.366 Category[1322:303] 我是分类方法Test2

2013-08-02 15:47:57.367 Category[1322:303] 我是分类方法test3

2013-08-02 15:47:57.368 Category[1322:303] {'name':'dxw','id':10}