java 中 Hex的转换

CHexConver.java

package mobi.dzs.util;

/**
 * 16进制值与String/Byte之间的转换
 * @author JerryLi
 * @email lijian@dzs.mobi
 * @data 2011-10-16
 * */
public class CHexConver
{
	/** 
	 * 字符串转换成十六进制字符串
	 * @param String 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 String str 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 byte[] 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[n] & 0xFF);
            sb.append((stmp.length()==1)? "0"+stmp : stmp);
            sb.append(" ");
        }
        return sb.toString().toUpperCase().trim();
    }
    
    /**
     * bytes字符串转换为Byte值
     * @param String src Byte字符串，每个Byte之间没有分隔符
     * @return byte[]
     */
    public static byte[] hexStr2Bytes(String src)
    {
        int m=0,n=0;
        int l=src.length()/2;
        System.out.println(l);
        byte[] ret = new byte[l];
        for (int i = 0; i < l; i++)
        {
            m=i*2+1;
            n=m+1;
            ret[i] = Byte.decode("0x" + src.substring(i*2, m) + src.substring(m,n));
        }
        return ret;
    }

    /**
     * String的字符串转换成unicode的String
     * @param String strText 全角字符串
     * @return String 每个unicode之间无分隔符
     * @throws Exception
     */
    public static String strToUnicode(String strText)
    	throws Exception
    {
        char c;
        StringBuilder str = new StringBuilder();
        int intAsc;
        String strHex;
        for (int i = 0; i < strText.length(); i++)
        {
            c = strText.charAt(i);
            intAsc = (int) c;
            strHex = Integer.toHexString(intAsc);
            if (intAsc > 128)
            	str.append("\\u" + strHex);
            else // 低位在前面补00
            	str.append("\\u00" + strHex);
        }
        return str.toString();
    }
    
    /**
     * unicode的String转换成String的字符串
     * @param String hex 16进制值字符串 （一个unicode为2byte）
     * @return String 全角字符串
     */
    public static String unicodeToString(String hex)
    {
        int t = hex.length() / 6;
        StringBuilder str = new StringBuilder();
        for (int i = 0; i < t; i++)
        {
            String s = hex.substring(i * 6, (i + 1) * 6);
            // 高位需要补上00再转
            String s1 = s.substring(2, 4) + "00";
            // 低位直接转
            String s2 = s.substring(4);
            // 将16进制的string转为int
            int n = Integer.valueOf(s1, 16) + Integer.valueOf(s2, 16);
            // 将int转换为字符
            char[] chars = Character.toChars(n);
            str.append(new String(chars));
        }
        return str.toString();
    }
}

gistfile1.java

///
String hexStr = "0123456789ABCDEF";
 long i = Long.valueOf(hexStr, 16);
 System.out.println(Long.toHexString(i));

///
public static String toHexString(byte[] ba) {
    StringBuilder str = new StringBuilder();
    for(int i = 0; i < ba.length; i++)
        str.append(String.format("%x", ba[i]));
    return str.toString();
}

public static String fromHexString(String hex) {
    StringBuilder str = new StringBuilder();
    for (int i = 0; i < hex.length(); i+=2) {
        str.append((char) Integer.parseInt(hex.substring(i, i + 2), 16));
    }
    return str.toString();
}

///
byte[] bytes = string.getBytes(CHARSET); // you didn't say what charset you wanted
BigInteger bigInt = new BigInteger(bytes);
String hexString = bigInt.toString(16); // 16 is the radix

HexStr.java

import org.apache.commons.codec.DecoderException;
import org.apache.commons.codec.binary.Hex;

import java.math.BigInteger;
import java.util.Arrays;

/**
 * Date: 2013-06-26 3:45 PM
 *
 * @author WangChengyi
 */
public class HexStr {
    public static String toHex(String arg) {
        return String.format("%040x", new BigInteger(arg.getBytes(/*YOUR_CHARSET?*/)));
        return String.format("%x", new BigInteger(arg.getBytes(/*YOUR_CHARSET?*/)));
    }

    public static void main2(String[] args) throws DecoderException {
        System.out.println(toHex("mat12345"));
        System.out.println(Hex.encodeHex("mat12345".getBytes()));
        System.out.println(new String(Hex.decodeHex("00006d61743132333435".toCharArray())));
    }
}

StringToHex.java

/**
 * Date: 2013-06-26 3:56 PM
 *
 * @author WangChengyi
 */
public class StringToHex {
    public String convertStringToHex(String str){

        char[] chars = str.toCharArray();

        StringBuffer hex = new StringBuffer();
        for(int i = 0; i < chars.length; i++){
            hex.append(Integer.toHexString((int)chars[i]));
        }

        return hex.toString();
    }

    public String convertHexToString(String hex){

        StringBuilder sb = new StringBuilder();
        StringBuilder temp = new StringBuilder();

        //49204c6f7665204a617661 split into two characters 49, 20, 4c...
        for( int i=0; i<hex.length()-1; i+=2 ){

            //grab the hex in pairs
            String output = hex.substring(i, (i + 2));
            //convert hex to decimal
            int decimal = Integer.parseInt(output, 16);
            //convert the decimal to character
            sb.append((char)decimal);

            temp.append(decimal);
        }
        System.out.println("Decimal : " + temp.toString());

        return sb.toString();
    }

    public static void main(String[] args) {

        StringToHex strToHex = new StringToHex();
        System.out.println("\n***** Convert ASCII to Hex *****");
        String str = "I Love Java!";
        System.out.println("Original input : " + str);

        String hex = strToHex.convertStringToHex(str);

        System.out.println("Hex : " + hex);

        System.out.println("\n***** Convert Hex to ASCII *****");
        System.out.println("Hex : " + hex);
        System.out.println("ASCII : " + strToHex.convertHexToString(hex));
    }
}

About CHexConver.java method hexStr2Str on the line 40 _maybe there are some bug.
For example, Byte.decode("0xcc") will not be executed，although 0xcc isn't a acsii value.
Here are my code：
public static byte[] HexStringToBinary(String src){ int m=0,n=0; int len=src.length()/2; System.out.println(len); byte[] ret = new byte[len]; for (int i = 0; i < len; i++) { m=i*2+1; n=m+1; //Height nibble int h = Byte.decode("0x" + src.substring(i*2, m))<<4; //Low nibble int l=Byte.decode("0x"+ src.substring(m,n)); ret[i]=(byte)(h|l); } return ret; }