byte[]数组和int之间如何互相转换呢?

int与byte[]之间的转换

 
/**  
* 将int数值转换为占四个字节的byte数组
* @param value  
*            要转换的int值 
* @return byte数组 
*/    
public static byte[] intToBytes( int value )   
{   
    byte[] src = new byte[4];  
    src[3] =  (byte) ((value>>24) & 0xFF);  
    src[2] =  (byte) ((value>>16) & 0xFF);  
    src[1] =  (byte) ((value>>8) & 0xFF);    
    src[0] =  (byte) (value & 0xFF);                  
    return src;   
}  
 /**  
    * 将int数值转换为占四个字节的byte数组 
    */    
public static byte[] intToBytes2(int value)   
{   
    byte[] src = new byte[4];  
    src[0] = (byte) ((value>>24) & 0xFF);  
    src[1] = (byte) ((value>>16)& 0xFF);  
    src[2] = (byte) ((value>>8)&0xFF);    
    src[3] = (byte) (value & 0xFF);       
    return src;  
}  

byte[]转int

/**  
    * byte数组中取int数值
    * @param src  
    *            byte数组  
    * @param offset  
    *            从数组的第offset位开始  
    * @return int数值  
    */    
public static int bytesToInt(byte[] src, int offset) {  
    int value;    
    value = (int) ((src[offset] & 0xFF)   
            | ((src[offset+1] & 0xFF)<<8)   
            | ((src[offset+2] & 0xFF)<<16)   
            | ((src[offset+3] & 0xFF)<<24));  
    return value;  
}  
  
 /**  
    * byte数组中取int数值，本方法适用于(低位在后，高位在前)的顺序。和intToBytes2（）配套使用 
    */  
public static int bytesToInt2(byte[] src, int offset) {  
    int value;    
    value = (int) ( ((src[offset] & 0xFF)<<24)  
            |((src[offset+1] & 0xFF)<<16)  
            |((src[offset+2] & 0xFF)<<8)  
            |(src[offset+3] & 0xFF));  
    return value;  
}  

int与byte[]之间的转换

 /**  
    * 将int数值转换为占四个字节的byte数组 
    * @param value  
    *            要转换的int值 
    * @return byte数组 
    */    
public static byte[] intToBytes(int value)   
{   
    byte[] byte_src = new byte[4];  
    byte_src[3] = (byte) ((value & 0xFF000000)>>24);  
    byte_src[2] = (byte) ((value & 0x00FF0000)>>16);  
    byte_src[1] = (byte) ((value & 0x0000FF00)>>8);    
    byte_src[0] = (byte) ((value & 0x000000FF));          
    return byte_src;  
}  

byte[]转int

 /**  
    * byte数组中取int数值
    *   
    * @param ary  
    *            byte数组  
    * @param offset  
    *            从数组的第offset位开始  
    * @return int数值  
    */    
public static int bytesToInt(byte[] ary, int offset) {  
    int value;    
    value = (int) ((ary[offset]&0xFF)   
            | ((ary[offset+1]<<8) & 0xFF00)  
            | ((ary[offset+2]<<16)& 0xFF0000)   
            | ((ary[offset+3]<<24) & 0xFF000000));  
    return value;  
}