字符串和byte[]的转换

 1     public static String bytesToHexString(byte[] src){
 2         StringBuilder stringBuilder = new StringBuilder("");
 3         if (src == null || src.length <= 0) {
 4             return null;
 5         }
 6         for (int i = 0; i < src.length; i++) {
 7             int v = src[i] & 0xFF;
 8             String hv = Integer.toHexString(v).toUpperCase();
 9             if (hv.length() < 2) {
10                 stringBuilder.append(0);
11             }
12             stringBuilder.append(hv);
13         }
14         return stringBuilder.toString();
15     }
16     //这个是为了转15693的数据专用的，略去第一个字符，接下来中间每5个字符取后面4个字符，然后将其转为字符串
17     //为了存储用
18     public static String bytesToHexString1(byte[] src){
19         StringBuilder stringBuilder = new StringBuilder("");
20         if (src == null || src.length <= 0) {
21             return null;
22         }
23         for (int i = 2; i < src.length; i++) {
24             if(((i-1) % 5 == 0) && (i > 2))
25                 continue;
26             int v = src[i] & 0xFF;
27             String hv = Integer.toHexString(v).toUpperCase();
28             if (hv.length() < 2) {
29                 stringBuilder.append(0);
30             }
31             stringBuilder.append(hv);
32         }
33         return stringBuilder.toString();
34     }
35     //这个是为了转15693的数据专用的，略去第一个字符，接下来中间每5个字符取后面4个字符，然后将其转为字符串
36     //为了显示用
37     public static String bytesToHexString2(byte[] src){
38         StringBuilder stringBuilder = new StringBuilder("");
39         if (src == null || src.length <= 0) {
40             return null;
41         }
42         for (int i = 2; i < src.length; i++) {
43             if(((i-1) % 5 == 0) && (i > 2))
44                 continue;
45             int v = src[i] & 0xFF;
46             String hv = Integer.toHexString(v).toUpperCase();
47             if (hv.length() < 2) {
48                 stringBuilder.append(0);
49             }
50             stringBuilder.append(hv + " ");
51         }
52         return stringBuilder.toString();
53     }
54 
55     /**
56      * Convert hex string to byte[]
57      * @param hexString the hex string
58      * @return byte[]
59      */
60     public static byte[] hexStringToBytes(String hexString) {
61         if (hexString == null || hexString.equals("")) {
62             return null;
63         }
64         hexString = hexString.toUpperCase();
65         int length = hexString.length() / 2;
66         char[] hexChars = hexString.toCharArray();
67         byte[] d = new byte[length];
68         for (int i = 0; i < length; i++) {
69             int pos = i * 2;
70             d[i] = (byte) (charToByte(hexChars[pos]) << 4 | charToByte(hexChars[pos + 1]));
71         }
72         return d;
73     }
74     /**
75      * Convert char to byte
76      * @param c char
77      * @return byte
78      */
79     public static byte charToByte(char c) {
80         return (byte) "0123456789ABCDEF".indexOf(c);
81     }