先来打一下实例：
创建一个Person类：
Person.h:
#import <Foundation/Foundation.h>
@interface Person : NSObject<NSCopying>
@property(nonatomic,assign) int age;
@property(nonatomic,retain) NSString *name;
@end Person.m:
#import "Person.h"
@implementation Person
- (id)init
{
self = [super init];
if (self) {
self.name = @"xiaoming";
self.age = 22;
}
return self;
}
//构造拷贝函数,虽然说内存管理的原则是谁retain谁release，但是对copy来说比较特殊，是放在外面release的
-(id)copyWithZone:(NSZone *)zone
{
Person *p = [[Person allocWithZone:zone] init];
p.name = self.name; //浅拷贝，只是拷贝了地址
p.age = self.age;
//深拷贝
//p.name = [self.name copy];//内容拷贝一份
return p;
}
- (void)dealloc
{
[_name release];
[super dealloc];
}
@end
main:
#import <Foundation/Foundation.h>
#import "Person.h"
int main(int argc, const char * argv[])
{
@autoreleasepool {
Person *p = [[Person alloc] init];
p.age = 11;
NSMutableString *str = [NSMutableString stringWithFormat:@"xiaohua"];
p.name = str;
NSLog(@"person age = %d name = %@",p.age,p.name);
Person *p1 = [p copy];
[str appendString:@"1"]; //在原来的基础上加1
NSLog(@"person age = %d name = %@",p.age,p.name); //验证原来的对象是否改变
NSLog(@"p1 age = %d name = %@",p1.age,p1.name); //打印当然的拷贝对象，这个要看前面的拷贝实现的函数是深拷贝还是浅拷贝
[p1 release];
[p release];
}
return 0;
}
浅拷贝结果：
2013-08-05 11:35:39.688 对象拷贝[862:303] person age = 11 name = xiaohua
2013-08-05 11:35:39.690 对象拷贝[862:303] person age = 11 name = xiaohua1
2013-08-05 11:35:39.691 对象拷贝[862:303] p1 age = 11 name = xiaohua1
深拷贝：
2013-08-05 11:39:26.579 对象拷贝[892:303] person age = 11 name = xiaohua
2013-08-05 11:39:26.581 对象拷贝[892:303] person age = 11 name = xiaohua1
2013-08-05 11:39:26.582 对象拷贝[892:303] p1 age = 11 name = xiaohua
