整型int和字符數組byte相互轉換的源程序
我目前在做一個有關網絡數據流的程序，需要實現整型int和字符數組byte相互轉換的功能，在網上搜索時沒找到相關文章，最後自己寫了一個封裝類，把它貼出來，興許別人能用上。
/**
* Name : ByteIntSwitch.java
* Date : Created on 2004/11/05 14:40
* Author : ZHUO Bibo
* Function: get an int, convert it to a byte[];
* get a byte[], convert it to int value;
*
* Compiler: Eclipse 3.0
*
*/
/**
* @author ZHUO Bibo
*
*/
public final class ByteIntSwitch {
/*
public static void main(String args[] ) {
int i = 1000;
byte[] b = toByteArray(i, 4);
System.out.println( "1000's bin: " + Integer.toBinaryString(1000));
System.out.println( "1000's hex: " + Integer.toHexString(1000));
}
*/
// 將iSource轉爲長度爲iArrayLen的byte數組，低位是低字節－－見代碼中舉例
// 若低位是高字節，只需for中從高到低遞減，而非從低到高遞增
public static byte[] toByteArray(int iSource, int iArrayLen) {
byte[] bLocalArr = new byte[iArrayLen];
// Note that an int is 4 bytes long
for ( int i = 0; (i < 4) && (i < iArrayLen); i++) {
bLocalArr[i] = (byte)( iSource>>8*i & 0xFF );
//System.out.print(Integer.toHexString(bLocalArr[i]) + " "); //for
// testing e.g: if 1000==iSource, then result is ffffffe8 03 00 00
}
return bLocalArr;
} // End of 'toByteArray()'
// 將byte數組bRefArr轉爲一個整數，低位是低字節－－見代碼中舉例
// 若低位是高字節，只需for中從低到高遞增，而非從高到低遞減
public static int toInt(byte[] bRefArr) {
int iOutcome = 0;
byte bLoop;
for ( int i = bRefArr.length - 1; i >= 0 ; i--) {
bLoop = bRefArr[i];
iOutcome += (bLoop & 0xFF) << (8 * (3 - i));
/*
* The another method is as follow, but the efficiency is low
switch (i) {
case 3: iOutcome += (bLoop & 0xFF)<<24; break;
case 2: iOutcome += (bLoop & 0xFF)<<16; break;
case 1: iOutcome += (bLoop & 0xFF)<<8; break;
case 0: iOutcome += bLoop & 0xFF; break;
}
*/ // System.out.println("iOutcome is: " + iOutcome +
// " bRefArr[" + i + "] is " + bRefArr[i] + " ");
} // End of for loop
return iOutcome;
} // End of 'toInt()'
} // End of 'public class ByteArrToInt '
