java十进制与任意进制之间转换

 

import java.util.HashMap;
import java.util.Map;
import java.util.Stack;
public class HexTransformatUtil {  
	/**
	 * 将十进制转换为任意进制值
	 * @param digths 转换后的进制最小位上，依次出现的字符值，比如26进制"ABCDEFGHIJKLMNOPQRSTUVWXYZ"
	 * @param num 将被转换的十进制值
	 * @param length 转换到指定字符串后，如果不足length长度位，自动补足最小值，比如26进制"ABCDEFGHIJKLMNOPQRSTUVWXYZ"将在最前补"a"
	 * @return
	 */
    public static String hex10ToAnly(String digths, int num,int length){  
        StringBuffer str = new StringBuffer("");  
        int base = digths.trim().length();
        if(0==num){
        	str.append(digths.charAt(0));
        }else{
        	Stack<Character> s = new Stack<Character>();  
            while(num != 0){  
                s.push(digths.charAt(num%base));  
                num/=base;  
            }  
            while(!s.isEmpty()){  
                str.append(s.pop());  
            }
        }
        String prefix = "";
        String suffix = str.toString();
        if(length>suffix.length()){
        	for(int count = 0;count<length-suffix.length();count++){
        		prefix = prefix + digths.charAt(0);
        	}
        }
        return prefix + suffix;  
    }  
    
    /**
	 * 将任意进制转换为十进制值
     * @param digths 转换前的进制最小位上，依次出现的字符值，比如26进制"ABCDEFGHIJKLMNOPQRSTUVWXYZ"
     * @param hexValue 转换前的进制字符串值
     * @return
     */
    public static int hexAnlyTo10(String digths, String hexValue){  
    	if(null==hexValue||"".equals(hexValue.trim()))  return 0;
    	int base = digths.trim().length();
    	
    	Map<String,Integer> digthMap = new HashMap<String,Integer>();
    	int count=0;
    	for(char item : digths.trim().toCharArray()){
    		digthMap.put(""+item, count);
    		count++;
    	}
    	String str = new StringBuffer(hexValue.trim()).reverse().toString();
    	int sum = 0;
    	for(int index = 0;index<str.length();index++){
    		sum = new Double(Math.pow(base, index)).intValue() * digthMap.get(""+str.charAt(index)) +sum;
    	}
    	return sum;
    }  
    
    public static void main(String[] args) {
    	//将十进制"0123456789"值55转换为26进制“ABCDEFGHIJKLMNOPQRSTUVWXYZ”对应的值，不需要格式化最后输出字符串
		System.out.println(hex10ToAnly("ABCDEFGHIJKLMNOPQRSTUVWXYZ", 55, 0));
		
		//将26进制“ABCDEFGHIJKLMNOPQRSTUVWXYZ”字符串值“CD”转换为十进制"0123456789"值55对应的值，不需要格式化最后输出字符串
		System.out.println(hexAnlyTo10("ABCDEFGHIJKLMNOPQRSTUVWXYZ", "CD" ));
	}
}