1 . NSData 与 NSString
2
3 NSData－> NSString
4
5 NSString *aString = [[NSString alloc] initWithData:adataencoding:NSUTF8StringEncoding];
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7
8
9 NSString－>NSData
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11 NSString *aString = @"1234abcd";
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13 NSData *aData = [aString dataUsingEncoding: NSUTF8StringEncoding];
14 .NSData 与 Byte
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16 NSData－> Byte数组
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18 NSString *testString = @"1234567890";
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20 NSData *testData = [testString dataUsingEncoding: NSUTF8StringEncoding];
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22 Byte *testByte = (Byte *)[testData bytes];
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24 for(int i=0;i<[testData length];i++)
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26 printf("testByte = %d\n",testByte[i]);
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28
29
30 Byte数组－> NSData
31
32 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};
33
34 NSData *adata = [[NSData alloc] initWithBytes:byte length:24];
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36
37
38 Byte数组－>16进制数
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40 Byte *bytes = (Byte *)[aData bytes];
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42 NSString *hexStr=@"";
43
44 for(int i=0;i<[encryData length];i++)
45
46 {
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48 NSString *newHexStr = [NSString stringWithFormat:@"%x",bytes[i]&0xff];///16进制数
49
50 if([newHexStr length]==1)
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52 hexStr = [NSString stringWithFormat:@"%@0%@",hexStr,newHexStr];
53
54 else
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56 hexStr = [NSString stringWithFormat:@"%@%@",hexStr,newHexStr];
57
58 }
59
60 NSLog(@"bytes 的16进制数为:%@",hexStr);
61 进制数－>Byte数组
62
63 ///// 将16进制数据转化成Byte 数组
64
65 NSString *hexString = @"3e435fab9c34891f"; //16进制字符串
66
67 int j=0;
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69 Byte bytes[128]; ///3ds key的Byte 数组， 128位
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71 for(int i=0;i<[hexString length];i++)
72
73 {
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75 int int_ch; /// 两位16进制数转化后的10进制数
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77
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79 unichar hex_char1 = [hexString characterAtIndex:i]; ////两位16进制数中的第一位(高位*16)
80
81 int int_ch1;
82
83 if(hex_char1 >= '0' && hex_char1 <='9')
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85 int_ch1 = (hex_char1-48)*16; //// 0 的Ascll - 48
86
87 else if(hex_char1 >= 'A' && hex_char1 <='F')
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89 int_ch1 = (hex_char1-55)*16; //// A 的Ascll - 65
90
91 else
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93 int_ch1 = (hex_char1-87)*16; //// a 的Ascll - 97
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95 i++;
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97
98
99 unichar hex_char2 = [hexString characterAtIndex:i]; ///两位16进制数中的第二位(低位)
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101 int int_ch2;
102
103 if(hex_char2 >= '0' && hex_char2 <='9')
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105 int_ch2 = (hex_char2-48); //// 0 的Ascll - 48
106
107 else if(hex_char1 >= 'A' && hex_char1 <='F')
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109 int_ch2 = hex_char2-55; //// A 的Ascll - 65
110
111 else
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113 int_ch2 = hex_char2-87; //// a 的Ascll - 97
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115
116
117 int_ch = int_ch1+int_ch2;
118
119 NSLog(@"int_ch=%d",int_ch);
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121 bytes[j] = int_ch; ///将转化后的数放入Byte数组里
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123 j++;
124
125 }
126
127 NSData *newData = [[NSData alloc] initWithBytes:bytes length:128];
128
129 NSLog(@"newData=%@",newData);
130 . NSData 与 UIImage
131
132 NSData－>UIImage
133
134 UIImage *aimage = [UIImage imageWithData: imageData];
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136
137
138 //例：从本地文件沙盒中取图片并转换为NSData
139
140 NSString *path = [[NSBundle mainBundle] bundlePath];
141
142 NSString *name = [NSString stringWithFormat:@"ceshi.png"];
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144 NSString *finalPath = [path stringByAppendingPathComponent:name];
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146 NSData *imageData = [NSData dataWithContentsOfFile: finalPath];
147
148 UIImage *aimage = [UIImage imageWithData: imageData];
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150
151
152 UIImage－> NSData
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154 NSData *imageData = UIImagePNGRepresentation(aimae);
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