NSData，NSImage,NSDictionary,NSString，NSInteger，Float，NSURL 等等互相转换

NSData，NSImage,NSDictionary,NSString，NSInteger，Float，NSURL 等等互相转换  

 

一：NSString和NSURL 转换

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1. //NSString->NSURL  
2. NSString *urlString=[@"http://www.google.com" stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];  
3. NSURL *url=[NSURL URLWithString:urlString];   
4. //NSURL->NSString   
5. NSString *urlString=[[url absoluteString] stringByReplacingPercentEscapesUsingEncoding:NSUTF8StringEncoding];  

二：NSString和NSData转换（即可作json串互相转换）

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1. //NSData－> NSString  
2. NSString *testString = [[NSString alloc] initWithData:testData encoding:NSUTF8StringEncoding];  
3. //NSString－>NSData  
4. NSString *aString = @"我是NSString";  
5. NSData *testData = [testString dataUsingEncoding: NSUTF8StringEncoding];  

三：NSData和NSImage转换

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1. //NSData－>UIImage  
2. UIImage *testImage = [UIImage imageWithData: imageData];  
3. //UIImage->NSData  
4. NSData *imageData = UIImagePNGRepresentation(testImage)  
5. //或者  
6. NSData *imageData = UIImageJPEGRepresentation(testImage,1.0)  

四：NSData和NSDictionary转换

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1. //NSData-->NSDictionary  
2. NSDictionary *testDict = [NSJSONSerialization JSONObjectWithData:testData options:NSJSONReadingMutableContainers error:nil]  
3. //或者  
4. NSKeyedUnarchiver *unarchiver = [[NSKeyedUnarchiver alloc] initForReadingWithData:testData];    
5. NSDictionary *myDictionary = [[unarchiver decodeObjectForKey:@"Some Key Value"] retain];    
6. [unarchiver finishDecoding];  
7. //NSDictionay --> NSData  
8. NSMutableData *data = [[NSMutableData alloc] init];    
9. NSKeyedArchiver *archiver = [[NSKeyedArchiver alloc] initForWritingWithMutableData:data];    
10. [archiver encodeObject:params forKey:@"Some Key Value"];    
11. [archiver finishEncoding];  

五：NSDictionary和JSON转换

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1. //NSDictionary -> JSON:  //这个方法是SBJson类库里的，需要导入SBJson.h  
2. NSString *jsonStr=[dict JSONRepresentation];  
3. //建议（特别是http取回来的jsonStr转换如下）  
4. //JSON->NSDictionary:  
5. NSData *jsonData = [testJsonStr dataUsingEncoding:NSUTF8StringEncoding];  
6. NSDictionary *dict = [NSJSONSerialization JSONObjectWithData:jsonData options:NSJSONReadingMutableContainers error:nil]  

//摘录其他同学的

NSData 与 Byte
NSData－> Byte数组
NSString *testString = @"1234567890";
NSData *testData = [testString dataUsingEncoding: NSUTF8StringEncoding];
Byte *testByte = (Byte *)[testData bytes];
for(int i=0;i<[testData length];i++)
printf("testByte = %d ",testByte[i]);

Byte数组－> NSData
Byte byte[] = {0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23};
NSData *adata = [[NSData alloc] initWithBytes:byte length:24];

Byte数组－>16进制数
Byte *bytes = (Byte *)[aData bytes];
NSString *hexStr=@"";
for(int i=0;i<[encryData length];i++)
{
NSString *newHexStr = [NSString stringWithFormat:@"%x",bytes[i]&0xff]; ///16进制数
if([newHexStr length]==1)
hexStr = [NSString stringWithFormat:@"%@0%@",hexStr,newHexStr];
else
hexStr = [NSString stringWithFormat:@"%@%@",hexStr,newHexStr];
}
NSLog(@"bytes 的16进制数为:%@",hexStr);