iOS NSDictionary、NSData、JSON数据类型相互转换
2015-12-05 15:35
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iOS经常需要用到数据类型的转换,下面列举一下常用类型的转换。 1.NSDictionary类型转换为NSData类型: [cpp] view plaincopy //NSDictionary -> NSData: NSDictionary *params = [NSDictionary dictionaryWithObjectsAndKeys: @"balance", @"key", @"remaining balance", @"label", @"45", @"value", @"USD", @"currencyCode",nil]; NSMutableData *data = [[NSMutableData alloc] init]; NSKeyedArchiver *archiver = [[NSKeyedArchiver alloc] initForWritingWithMutableData:data]; [archiver encodeObject:params forKey:@"Some Key Value"]; [archiver finishEncoding]; 2.NSData类型转换为NSDictionary类型: [cpp] view plaincopy //NSData -> NSDictionary NSData *data = [[NSMutableData alloc] initWithContentsOfFile:[self dataFilePath]]; NSKeyedUnarchiver *unarchiver = [[NSKeyedUnarchiver alloc] initForReadingWithData:data]; NSDictionary *myDictionary = [[unarchiver decodeObjectForKey:@"Some Key Value"] retain]; [unarchiver finishDecoding]; [unarchiver release]; [data release]; 3.NSDictionary类型转换为JSON数据类型: [cpp] view plaincopy //NSDictionary -> JSON: NSString *jsonStr=[dict JSONRepresentation]; 注意JSON与NSDictionary类型的转换一般会用到第三方公开的JSON库,读者可以在网上找到很多。 1. NSData 与 NSString NSData-> NSString NSString *aString = [[NSString alloc] initWithData:adata encoding:NSUTF8StringEncoding]; NSString->NSData NSString *aString = @"1234abcd"; NSData *aData = [aString dataUsingEncoding: NSUTF8StringEncoding]; 2.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\n",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); 16进制数->Byte数组 ///// 将16进制数据转化成Byte 数组 NSString *hexString = @"3e435fab9c34891f"; //16进制字符串 int j=0; Byte bytes[128]; ///3ds key的Byte 数组, 128位 for(int i=0;i<[hexString length];i++) { int int_ch; /// 两位16进制数转化后的10进制数 unichar hex_char1 = [hexString characterAtIndex:i]; ////两位16进制数中的第一位(高位*16) int int_ch1; if(hex_char1 >= '0' && hex_char1 <='9') int_ch1 = (hex_char1-48)*16; //// 0 的Ascll - 48 else if(hex_char1 >= 'A' && hex_char1 <='F') int_ch1 = (hex_char1-55)*16; //// A 的Ascll - 65 else int_ch1 = (hex_char1-87)*16; //// a 的Ascll - 97 i++; unichar hex_char2 = [hexString characterAtIndex:i]; ///两位16进制数中的第二位(低位) int int_ch2; if(hex_char2 >= '0' && hex_char2 <='9') int_ch2 = (hex_char2-48); //// 0 的Ascll - 48 else if(hex_char1 >= 'A' && hex_char1 <='F') int_ch2 = hex_char2-55; //// A 的Ascll - 65 else int_ch2 = hex_char2-87; //// a 的Ascll - 97 int_ch = int_ch1+int_ch2; NSLog(@"int_ch=%d",int_ch); bytes[j] = int_ch; ///将转化后的数放入Byte数组里 j++; } NSData *newData = [[NSData alloc] initWithBytes:bytes length:128]; NSLog(@"newData=%@",newData); 3. NSData 与 UIImage NSData->UIImage UIImage *aimage = [UIImage imageWithData: imageData]; //例:从本地文件沙盒中取图片并转换为NSData NSString *path = [[NSBundle mainBundle] bundlePath]; NSString *name = [NSString stringWithFormat:@"ceshi.png"]; NSString *finalPath = [path stringByAppendingPathComponent:name]; NSData *imageData = [NSData dataWithContentsOfFile: finalPath]; UIImage *aimage = [UIImage imageWithData: imageData]; UIImage-> NSData NSData *imageData = UIImagePNGRepresentation(aimae);
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