二进制直接转16进制

[wasdasdfqwer]

自己尝试着写了第一种，后来在网友提示下修改了下写了第二种，
想问下还有什么好的思路和优化的地方。

/** 
	 * 10 0010 1111 按每4个一组分开，在binarys[]中找到对应的下标idx，对应的hexs[idx]相连接。
	 * @param binaryStr 10 0010 1111
	 * @return  hexStr 22F
	 */
		public static String binaryToHex(String binaryStr){
		String binarys[] = new String[]{
				"0000","0001","0010","0011",
				"0100","0101","0110","0111",
				"1000","1001","1010","1011",
				"1100","1101","1110","1111"
				};
		String hexs[] = new String[]{
				"0","1","2","3",
				"4","5","6","7",
				"8","9","A","B",
				"C","D","E","F"
		};
		int n = binaryStr.length()%4;
		if(n != 0){
			int zeroNum = 0;
			zeroNum = 4 - n;
			for(int i=0; i< zeroNum; i++){
				binaryStr = "0"+binaryStr;
			}
			n = n+1;
		}
		String hexStr = "";
		for(int j=0; j<binaryStr.length()/4; j++){
			String temp = binaryStr.substring(j*4, (j+1)*4);
			int index = -1;
			for(int k=0;k<16;k++){
				if(binarys[k].equals(temp)){
					index = k;
				}
			}
			if(index != -1){
				hexStr = hexStr + hexs[index];
			}
		}
		
		return hexStr;
	}

	/** 
	 * 10 0010 1111 按每4个一组分开，转化为int型数据index，然后hexs[index]相加。
	 * @param binaryStr 10 0010 1111
	 * @return hexStr 22F
	 */
	public static String binaryToHex2(String binaryStr){
		
		String hexs[] = new String[]{
				"0","1","2","3",
				"4","5","6","7",
				"8","9","A","B",
				"C","D","E","F"
		};
		int n = binaryStr.length()%4;
		if(n != 0){
			int zeroNum = 0;
			zeroNum = 4 - n;
			for(int i=0; i< zeroNum; i++){
				binaryStr = "0"+binaryStr;
			}
			n = n+1;
		}
		String hexStr = "";
		for(int j=0; j<binaryStr.length()/4; j++){
			String temp = binaryStr.substring(j*4, (j+1)*4);
			
			int index =0;//下标 index=15,则对应输出 hexs[15] = F
			int i = 3;
			for(char c : temp.toCharArray()) {
				String str = new String(new char[]{c});
				index = index + ((Integer.parseInt(str))<<i) ;
				i--;
			}
			hexStr = hexStr + hexs[index];
		}
		
		return hexStr;
		
	}

[wasdasdfqwer]

本来想怎么直接转呢？但是可能是10进制的思维惯性根深蒂固，思想上转不过来，从10进制转为其他进制都好理解，除2（16）取取。

[huasuoworld]

你可以参考jdk中Integer的进制转换，先把二进制转成10进制，再转成16进制。

Integer.toHexString(Integer.valueOf("1010",2))

[wasdasdfqwer]

java Integer.java中的： System.out.println(toUnsignedString(559,4));//打印16进制结果 22f

 final static char[] digits = {
	        '0' , '1' , '2' , '3' , '4' , '5' ,
	        '6' , '7' , '8' , '9' , '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'
	    };
	 private static String toUnsignedString(int i, int shift) {
	        char[] buf = new char[32];
	        int charPos = 32;
	        int radix = 1 << shift;
	        int mask = radix - 1;
	        do {
	            buf[--charPos] = digits[i & mask];
	            i >>>= shift;
	        } while (i != 0);

	        return new String(buf, charPos, (32 - charPos));
	    }

[huasuoworld]

你用计算器（程序员模式）看下，559的十六进制是22F啊。