java格式转换的一些方法

//byte 与 int 的相互转换  
    public static byte intToByte(int x) {  
        return (byte) x;  
    }  
      
    public static int byteToInt(byte b) {  
        //Java 总是把 byte 当做有符处理；我们可以通过将其和 0xFF 进行二进制与得到它的无符值  
        return b & 0xFF;  
    }  
      
    //byte 数组与 int 的相互转换  
    public static int byteArrayToInt(byte[] b) {  
        return   b[3] & 0xFF |  
                (b[2] & 0xFF) << 8 |  
                (b[1] & 0xFF) << 16 |  
                (b[0] & 0xFF) << 24;  
    }  
  
    public static byte[] intToByteArray(int a) {  
        return new byte[] {  
            (byte) ((a >> 24) & 0xFF),  
            (byte) ((a >> 16) & 0xFF),     
            (byte) ((a >> 8) & 0xFF),     
            (byte) (a & 0xFF)  
        };  
    }  
  
    //byte 数组与 long 的相互转换  
    public static byte[] longToBytes(long x) {  
        buffer.putLong(0, x);  
        return buffer.array();  
    }  
  
    public static long bytesToLong(byte[] bytes) {  
        buffer.put(bytes, 0, bytes.length);  
        buffer.flip();//need flip   
        return buffer.getLong();  
    } 

/**

* 将short转成byte[2]

*

* @param a

* @return

*/

public static byte[] short2Byte(short a)

{

byte[] b = new byte[2];

b[0] = (byte) (a >> 8);

b[1] = (byte) (a);

return b;
}

/**

* 将short转成byte[2]

*

* @param a

* @param b

* @param offset b中的偏移量

*/

public static void short2Byte(short a, byte[] b, int offset)

{

b[offset] = (byte) (a >> 8);

b[offset + 1] = (byte) (a);

}

/**

* 字符串转换成十六进制字符串

*

* @param str 待转换的ASCII字符串

* @return String 每个Byte之间空格分隔，如: [61 6C 6B]

*/

public static String str2HexStr(String str)

{

char[] chars = "0123456789ABCDEF".toCharArray();

StringBuilder sb = new StringBuilder("");

byte[] bs = str.getBytes();

int bit;

for (int i = 0; i < bs.length; i++)

{

bit = (bs[i] & 0x0f0) >> 4;

sb.append(chars[bit]);

bit = bs[i] & 0x0f;

sb.append(chars[bit]);

sb.append(' ');

}

return sb.toString().trim();

}

/**

* 十六进制转换字符串

*

* @param hexStr Byte字符串(Byte之间无分隔符 如:[616C6B])

* @return String 对应的字符串

*/

public static String hexStr2Str(String hexStr)

{

String str = "0123456789ABCDEF";

char[] hexs = hexStr.toCharArray();

byte[] bytes = new byte[hexStr.length() / 2];

int n;

for (int i = 0; i < bytes.length; i++)

{

n = str.indexOf(hexs[2 * i]) * 16;

n += str.indexOf(hexs[2 * i + 1]);

bytes[i] = (byte) (n & 0xff);

}

return new String(bytes);

}

/**

* bytes转换成十六进制字符串

*

* @param b byte数组

* @return String 每个Byte值之间空格分隔

*/

public static String byte2HexStr(byte[] b)

{

String stmp = "";

StringBuilder sb = new StringBuilder("");

for (int n = 0; n < b.length; n++)

{

stmp = Integer.toHexString(b
& 0xFF);

sb.append((stmp.length() == 1) ? "0" + stmp : stmp);

}

return sb.toString().toUpperCase().trim();

}

/**

* bytes字符串转换为Byte值

*

* @param src Byte字符串，每个Byte之间没有分隔符

* @return byte[]

*/

public static byte[] hexStr2Bytes(String src)

{

String hexString = src.toLowerCase();

final byte[] byteArray = new byte[hexString.length() / 2];

int k = 0;

for (int i = 0; i < byteArray.length; i++)

{

// 转换成字节需要两个16进制的字符，高位在先

// 将hex 转换成byte "&" 操作为了防止负数的自动扩展

// hex转换成byte 其实只占用了4位，然后把高位进行右移四位

// 然后“|”操作 低四位 就能得到 两个 16进制数转换成一个byte.

byte high = (byte) (Character.digit(hexString.charAt(k), 16) & 0xff);

byte low = (byte) (Character.digit(hexString.charAt(k + 1), 16) & 0xff);

byteArray[i] = (byte) (high << 4 | low);

k += 2;

}

return byteArray;

}

/**

* bytes转换成十六进制字符串0补FF

*

* @param b byte数组

* @return String 每个Byte值之间空格分隔

*/

public static String byte2HexStr2(byte[] b)

{

String stmp = "";

StringBuilder sb = new StringBuilder("");

for (int n = 0; n < b.length; n++)

{

stmp = Integer.toHexString(b
& 0xFF);

if("0".equals(stmp)){

sb.append("FF");

}else {

sb.append((stmp.length() == 1) ? "0" + stmp : stmp);

}

}

return sb.toString().toUpperCase().trim();

}

/**

* bytes转换成十六进制字符串不补0

*

* @param b byte数组

* @return String 每个Byte值之间空格分隔

*/

public static String byte2HexStr1(byte[] b)

{

String stmp = "";

StringBuilder sb = new StringBuilder("");

for (int n = 0; n < b.length; n++)

{

stmp = Integer.toHexString(b
& 0xFF);

sb.append((stmp.length() == 1) ? "" + stmp : stmp);

}

return sb.toString().toUpperCase().trim();

}

/**

* bytes转换成十进制字符串

*

* @param b byte数组

* @return String 每个Byte值之间空格分隔

*/

public static String byte2DecimalStr(byte[] b)

{

String stmp = "";

StringBuilder sb = new StringBuilder("");

for (int n = 0; n <
9013
b.length; n++)

{

stmp = Integer.toString(b
& 0xFF);

sb.append((stmp.length() == 1) ? "0" + stmp : stmp);

}

return sb.toString().toUpperCase().trim();

}