byte数组转换成Base64字符编码

public class ConvertBytesToBase64 {
    // 下面的代码转换byte数组到 Base64
    private static char[] CharCode = {
    	'A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P',
    	'Q','R','S','T','U','V','W','X','Y','Z','a','b','c','d','e','f',
    	'g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v',
    	'w','x','y','z','0','1','2','3','4','5','6','7','8','9','+','/'
    	};
    private static String ConvertByte3ToString(byte[] bytes){
    	String temp = new String("");
    	temp += CharCode[((bytes[0])>>>2)&0x3f];
    	temp += CharCode[((bytes[0]&0x03)<<4)|((bytes[1]>>>4)&0x0f)];
    	temp += CharCode[((bytes[1]&0x0f)<<2)|((bytes[2]>>>6)&0x03)];
    	temp += CharCode[bytes[2]&0x3f];
    	return temp;
    }
    
    private static String ConvertByte2ToString(byte[] bytes){
    	String temp = new String("");
    	temp += CharCode[((bytes[0])>>>2)&0x3f];
    	temp += CharCode[((bytes[0]&0x03)<<4)|((bytes[1]>>>4)&0x0f)];
    	temp += CharCode[((bytes[1]&0x0f)<<2)];
    	temp += '=';
    	return temp;
    }
    
    private static String ConvertByteToString(byte[] bytes){
    	String temp = new String("");
    	temp += CharCode[((bytes[0])>>>2)&0x3f];
    	temp += CharCode[((bytes[0]&0x03)<<4)];
    	temp += "==";
    	return temp;
    }

    public static String BytesToBase64String(byte[] buffer){
    	String reslut = new String("");
		int length = buffer.length;
		int index = 0;
		for(index = 0;(index+3)<length;index+=3){
			byte[] temp = {buffer[index],buffer[index+1],buffer[index+2]};
			reslut += ConvertByte3ToString(temp);
		}
		if(length%3 == 1){
			byte[] temp = {buffer[length-1]};
			reslut += ConvertByteToString(temp);
		}else if(length%3 == 2){
			byte[] temp = {buffer[length-2],buffer[length-1]};
			reslut += ConvertByte2ToString(temp);
		}
    	return reslut;
    }
}

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http://my.oschina.net/u/251121/blog/65383