[JAVA]유용한 형변환 함수들

public class ByteUtil {
    private ByteUtil()
    {
    }

    public static final byte[] short2byte(short s)
    {
        byte dest[] = new byte[2];
        dest[1] = (byte)(s & 0xff);
        dest[0] = (byte)(s >>> 8 & 0xff);
        return dest;
    }

    public static final byte[] int2byte(int i)
    {
        byte dest[] = new byte[4];
        dest[3] = (byte)(i & 0xff);
        dest[2] = (byte)(i >>> 8 & 0xff);
        dest[1] = (byte)(i >>> 16 & 0xff);
        dest[0] = (byte)(i >>> 24 & 0xff);
        return dest;
    }

    public static final byte[] long2byte(long l)
    {
        byte dest[] = new byte[8];
        dest[7] = (byte)(int)(l & 255L);
        dest[6] = (byte)(int)(l >>> 8 & 255L);
        dest[5] = (byte)(int)(l >>> 16 & 255L);
        dest[4] = (byte)(int)(l >>> 24 & 255L);
        dest[3] = (byte)(int)(l >>> 32 & 255L);
        dest[2] = (byte)(int)(l >>> 40 & 255L);
        dest[1] = (byte)(int)(l >>> 48 & 255L);
        dest[0] = (byte)(int)(l >>> 56 & 255L);
        return dest;
    }

    public static final byte[] float2byte(float f)
    {
        byte dest[] = new byte[4];
        return setfloat(dest,0,f);
    }
    public static final byte[] double2byte(double d)
    {
        byte dest[] = new byte[8];
        return setdouble(dest,0,d);
    }

    public static final byte getbyte(byte src[], int offset)
    {
        return src[offset];
    }

    public static final byte[] getbytes(byte src[], int offset, int length)
    {
        byte dest[] = new byte[length];
        System.arraycopy(src, offset, dest, 0, length);
        return dest;
    }

    public static final short getshort(byte src[], int offset)
    {
        return (short)((src[offset] & 0xff) << 8 | src[offset + 1] & 0xff);
    }

    public static final int getint(byte src[], int offset)
    {
        return 
            (src[offset] & 0xff) << 24 | 
            (src[offset + 1] & 0xff) << 16 | 
            (src[offset + 2] & 0xff) << 8 | 
            src[offset + 3] & 0xff;
    }

    public static final long getlong(byte src[], int offset)
    {
        return 
            (long)getint(src, offset) << 32 | 
            (long)getint(src, offset + 4) & 0xffffffffL;
    }

    public static final float getfloat(byte src[], int offset)
    {
        return Float.intBitsToFloat(getint(src, offset));
    }

    public static final double getdouble(byte src[], int offset)
    {
        return Double.longBitsToDouble(getlong(src, offset));
    }

    public static final byte[] setbyte(byte dest[], int offset, byte b)
    {
        dest[offset] = b;
        return dest;
    }

    public static final byte[] setbytes(byte dest[], int offset, byte src[])
    {
        System.arraycopy(src, 0, dest, offset, src.length);
        return dest;
    }

    public static final byte[] setbytes(byte dest[], int offset, byte src[], int len)
    {
        System.arraycopy(src, 0, dest, offset, len);
        return dest;
    }

    public static final byte[] setshort(byte dest[], int offset, short s)
    {
        dest[offset] = (byte)(s >>> 8 & 0xff);
        dest[offset + 1] = (byte)(s & 0xff);
        return dest;
    }

    public static final byte[] setint(byte dest[], int offset, int i)
    {
        dest[offset] = (byte)(i >>> 24 & 0xff);
        dest[offset + 1] = (byte)(i >>> 16 & 0xff);
        dest[offset + 2] = (byte)(i >>> 8 & 0xff);
        dest[offset + 3] = (byte)(i & 0xff);
        return dest;
    }

    public static final byte[] setlong(byte dest[], int offset, long l)
    {
        setint(dest, offset, (int)(l >>> 32));
        setint(dest, offset + 4, (int)(l & 0xffffffffL));
        return dest;
    }

    public static final byte[] setfloat(byte dest[], int offset, float f)
    {
        return setint(dest, offset, Float.floatToIntBits(f));
    }

    public static final byte[] setdouble(byte dest[], int offset, double d)
    {
        return setlong(dest, offset, Double.doubleToLongBits(d));
    }
    //sjkim
    public static final byte[] string2byte(String s) {
        return string2byte(s,65535);
    }
    public static final byte[] string2byte(String s, int max) {
        if (s == null)
            return short2byte((short) 0);
        else {
            byte[] strBuf = s.getBytes();
            int len = strBuf.length;
            if (len == 0)
                return short2byte((short) 0);
            else if(len>max) len = max;
            else if (len > 65535) len = 65535;
            byte[] lenBuf = short2byte((short) len);

            byte[] rtnBuf = new byte[2 + len];

            System.arraycopy(lenBuf, 0, rtnBuf, 0, 2);
            System.arraycopy(strBuf, 0, rtnBuf, 2, len);
            return rtnBuf;
        }
    }

    public static final boolean isEquals(byte b[], String s)
    {
        if(b == null || s == null)
            return false;
        int slen = s.length();
        if(b.length != slen)
            return false;
        for(int i = slen; i-- > 0;)
            if(b[i] != s.charAt(i))
                return false;

        return true;
    }

    public static final boolean isEquals(byte a[], byte b[])
    {
        if(a == null || b == null)
            return false;
        if(a.length != b.length)
            return false;
        for(int i = a.length; i-- > 0;)
            if(a[i] != b[i])
                return false;

        return true;
    }

}

NOTE: Socket 으로 타 OS 와 주고 받을 목적이라면, 해당 OS 에서  short,int,long 
 값에 대한 내부적 표현이 다를 수 있으니 먼저 확인하고 사용하셔야 할 겁니다.


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제목 : Re: ByteUtil.java 글쓴이: 이원영(javaservice) 2005/03/19 20:41:57 조회수:1173 줄수:203

시간이 지나면서, 필요에 의해 추가시킨 메소드가 있습니다. ---------------------------8><------------------------------------------ /** * @(#) ByteUtil.java * Copyright 1999 by Java Service Network Community, KOREA. * All rights reserved. http://www.javaservice.net * * NOTICE ! You can copy or redistribute this code freely, * but you should not remove the information about the copyright notice * and the author. * * @author WonYoung Lee, lwy@javaservice.com */ package org.jsn.jdf.util; public class ByteUtil { private ByteUtil() { } public static final byte[] short2byte(short s) { byte dest[] = new byte[2]; dest[1] = (byte)(s & 0xff); dest[0] = (byte)(s >>> 8 & 0xff); return dest; } public static final byte[] int2byte(int i) { byte dest[] = new byte[4]; dest[3] = (byte)(i & 0xff); dest[2] = (byte)(i >>> 8 & 0xff); dest[1] = (byte)(i >>> 16 & 0xff); dest[0] = (byte)(i >>> 24 & 0xff); return dest; } public static final byte[] long2byte(long l) { byte dest[] = new byte[8]; dest[7] = (byte)(int)(l & 255L); dest[6] = (byte)(int)(l >>> 8 & 255L); dest[5] = (byte)(int)(l >>> 16 & 255L); dest[4] = (byte)(int)(l >>> 24 & 255L); dest[3] = (byte)(int)(l >>> 32 & 255L); dest[2] = (byte)(int)(l >>> 40 & 255L); dest[1] = (byte)(int)(l >>> 48 & 255L); dest[0] = (byte)(int)(l >>> 56 & 255L); return dest; } public static final byte[] float2byte(float f) { byte dest[] = new byte[4]; return setfloat(dest,0,f); } public static final byte[] double2byte(double d) { byte dest[] = new byte[8]; return setdouble(dest,0,d); } public static final byte getbyte(byte src[], int offset) { return src[offset]; } public static final byte[] getbytes(byte src[], int offset, int length) { byte dest[] = new byte[length]; System.arraycopy(src, offset, dest, 0, length); return dest; } public static final short getshort(byte src[], int offset) { return (short)((src[offset] & 0xff) << 8 | src[offset + 1] & 0xff); } public static final int getint(byte src[], int offset) { return (src[offset] & 0xff) << 24 | (src[offset + 1] & 0xff) << 16 | (src[offset + 2] & 0xff) << 8 | src[offset + 3] & 0xff; } public static final long getlong(byte src[], int offset) { return (long)getint(src, offset) << 32 | (long)getint(src, offset + 4) & 0xffffffffL; } public static final float getfloat(byte src[], int offset) { return Float.intBitsToFloat(getint(src, offset)); } public static final double getdouble(byte src[], int offset) { return Double.longBitsToDouble(getlong(src, offset)); } public static final byte[] setbyte(byte dest[], int offset, byte b) { dest[offset] = b; return dest; } public static final byte[] setbytes(byte dest[], int offset, byte src[]) { System.arraycopy(src, 0, dest, offset, src.length); return dest; } public static final byte[] setbytes(byte dest[], int offset, byte src[], int len) { System.arraycopy(src, 0, dest, offset, len); return dest; } public static final byte[] setshort(byte dest[], int offset, short s) { dest[offset] = (byte)(s >>> 8 & 0xff); dest[offset + 1] = (byte)(s & 0xff); return dest; } public static final byte[] setint(byte dest[], int offset, int i) { dest[offset] = (byte)(i >>> 24 & 0xff); dest[offset + 1] = (byte)(i >>> 16 & 0xff); dest[offset + 2] = (byte)(i >>> 8 & 0xff); dest[offset + 3] = (byte)(i & 0xff); return dest; } public static final byte[] setlong(byte dest[], int offset, long l) { setint(dest, offset, (int)(l >>> 32)); setint(dest, offset + 4, (int)(l & 0xffffffffL)); return dest; } public static final byte[] setfloat(byte dest[], int offset, float f) { return setint(dest, offset, Float.floatToIntBits(f)); } public static final byte[] setdouble(byte dest[], int offset, double d) { return setlong(dest, offset, Double.doubleToLongBits(d)); } public static final boolean isEquals(byte b[], String s) { if(b == null || s == null) return false; int slen = s.length(); if(b.length != slen) return false; for(int i = slen; i-- > 0;) if(b[i] != s.charAt(i)) return false; return true; } public static final boolean isEquals(byte a[], byte b[]) { if(a == null || b == null) return false; if(a.length != b.length) return false; for(int i = a.length; i-- > 0;) if(a[i] != b[i]) return false; return true; } } ---------------------------8><------------------------------------------ PS: 545 Re: TcpUtil.java http://www.javaservice.net/~java/bbs/read.cgi?m=devtip&b=javatip&c=r_p&n=1111232348 ------------------------------------------------------- 본 문서는 자유롭게 배포/복사 할 수 있으나 반드시 이 문서의 저자에 대한 언급을 삭제하시면 안됩니다 ================================================ 자바서비스컨설팅 이원영 Phone: 010-6239-6498 E-mail: lwy@javaservice.com MSN: javaservice@hanmail.net