objective-C中的序列化(serialize)与反序列化(deserialize)

最新推荐文章于 2025-09-09 00:23:52 发布

最新推荐文章于 2025-09-09 00:23:52 发布 · 157 阅读

转载自：http://www.cnblogs.com/yjmyzz/archive/2011/03/03/1969859.html

obj-c中有一类对象：NSArray,NSDictionary,NSString,NSNumber,NSDate,NSData以及它们的可变版本(指NSMutableArray,NSMutableDictionary...这一类) ，都可以方便的将自身的数据以某种格式(比如xml格式)序列化后保存成本地文件。

示例代码：NSArrayTest.h

 
       1  #import <Foundation/Foundation.h> 

       2  #define FILE_NAME @"/tmp/data.txt" 

       3  

       4  @interfaceNSArrayTest:NSObject{ 

       5  } 

       6  

       7  -(void) Test; 

       8  

       9  @end

NSArrayTest.m

 
       01  #import "NSArrayTest.h" 

       02  

       03  @implementationNSArrayTest 

       04  

       05  -(void) Test 

       06  { 

       07  NSArray*arr = [NSArrayarrayWithObjects:@"one",@"two",@"three",nil];//注:最后一个要以nil结尾 

       08  [arr writeToFile:FILE_NAME atomically:YES];//(序列化为xml格式后)保存文件 

       09   

       10  NSArray*arr2 = [NSArrayarrayWithContentsOfFile:FILE_NAME];//read file 

       11  NSLog(@"%@",arr2); 

       12  

       13  } 

       14  

       15  @end

运行结果：

2011-03-03 14:20:01.501 pList[1246:a0f] (
one,
two,
three
)

如果查看/tmp/data.txt，能看到下面的内容：

 
       1  <?xmlversion="1.0"encoding="UTF-8"?> 

       2  <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd"> 

       3  <plistversion="1.0"> 

       4  <array> 

       5  <string>one</string> 

       6  <string>two</string> 

       7  <string>three</string> 

       8  </array> 

       9  </plist>

即NSArray默认是以xml格式来序列化对象的.

如果你用来存放数据的类是自己定义的，并不是上面这些预置的对象，那么就要借助正式协议NSCoding来实现序列化和反序列化。

比如，我们有一个自己的类Sample.h

 
       01  #import <Foundation/Foundation.h> 

       02  

       03  @interfaceSample :NSObject<NSCoding> { 

       04  

       05  NSString* name; 

       06  intmagicNumber; 

       07  floatshoeSize; 

       08  NSMutableArray*subThingies; 

       09  } 

       10  

       11  @property(copy)NSString* name; 

       12  @propertyintmagicNumber; 

       13  @propertyfloatshoeSize; 

       14  @property(retain)NSMutableArray*subThingies; 

       15  

       16  

       17  -(id) initWithName:(NSString*)n magicNumber:(int)m shoeSize:(float) ss; 

       18  

       19  @end

这里我们定义几个不同类型的属性，有字符串，有整数，有浮点数，还有一个可变长的数组对象

Sample.m

 
       01  #import "Sample.h" 

       02  

       03  @implementationSample 

       04  

       05  @synthesizename; 

       06  @synthesizemagicNumber; 

       07  @synthesizeshoeSize; 

       08  @synthesizesubThingies; 

       09  

       10  -(id) initWithName:(NSString*)n magicNumber:(int)m shoeSize:(float)ss 

       11  { 

       12  if(self=[superinit]) 

       13  { 

       14  self.name = n; 

       15  self.magicNumber = m; 

       16  self.shoeSize = ss; 

       17  self.subThingies = [NSMutableArrayarray]; 

       18  } 

       19  return(self); 

       20  } 

       21  

       22  -(void) dealloc 

       23  { 

       24  [name release]; 

       25  [subThingies release]; 

       26  [superdealloc]; 

       27  } 

       28  

       29  //将对象编码(即:序列化) 

       30  -(void) encodeWithCoder:(NSCoder*)aCoder 

       31  { 

       32  [aCoder encodeObject:name forKey:@"name"]; 

       33  [aCoder encodeInt:magicNumber forKey:@"magicNumber"]; 

       34  [aCoder encodeFloat:shoeSize forKey:@"shoeSize"]; 

       35  [aCoder encodeObject:subThingies forKey:@"subThingies"]; 

       36  } 

       37  

       38  //将对象解码(反序列化) 

       39  -(id) initWithCoder:(NSCoder*)aDecoder 

       40  { 

       41  if(self=[superinit]) 

       42  { 

       43  self.name = [aDecoder decodeObjectForKey:@"name"]; 

       44  self.magicNumber = [aDecoder decodeIntForKey:@"magicNumber"]; 

       45  self.shoeSize = [aDecoder decodeFloatForKey:@"shoeSize"]; 

       46  self.subThingies = [aDecoder decodeObjectForKey:@"subThingies"]; 

       47  } 

       48  return(self); 

       49   

       50  } 

       51  

       52  

       53  -(NSString*) description 

       54  { 

       55  NSString*description = [NSStringstringWithFormat:@"%@:%d/%.1f %@",name,magicNumber,shoeSize,subThingies]; 

       56  return(description); 

       57  } 

       58  

       59  

       60  @end

注意其中的： encodeWithCoder与 initWithCoder，这是NSCoding协议中定义的二个方法，用来实现对象的编码与解码。其实现也不复杂，利用的是key-value的经典哈希结构。当然一般在编码中，对于key的名字字符串，建议用define以常量方式事先定义好，以避免开发人员字符串键入错误。

测试一下：

 
       01  #import <Foundation/Foundation.h> 

       02  #import "Sample.h" 

       03  

       04  intmain (intargc,constchar* argv[]) { 

       05  NSAutoreleasePool* pool = [[NSAutoreleasePoolalloc] init]; 

       06  

       07  Sample *s1 = [[Sample alloc] initWithName:@"thing1"magicNumber:42 shoeSize:10.5]; 

       08  [s1.subThingies addObject:@"1"]; 

       09  [s1.subThingies addObject:@"2"]; 

       10  NSLog(@"%@",s1); 

       11  NSData*data1 = [NSKeyedArchiverarchivedDataWithRootObject:s1];//将s1序列化后,保存到NSData中 

       12  [s1 release]; 

       13  [data1 writeToFile:@"/tmp/data.txt"atomically:YES];//持久化保存成物理文件 

       14   

       15  NSData*data2 = [NSDatadataWithContentsOfFile:@"/tmp/data.txt"];//读取文件 

       16  Sample *s2 = [NSKeyedUnarchiverunarchiveObjectWithData:data2];//反序列化 

       17  NSLog(@"%@",s2); 

       18   

       19  [pool drain]; 

       20  return0; 

       21  }