NumericHelper.java

package com.ycsoft.commons.helper;

import java.math.BigDecimal;


/**
 * 提供高精度的运算支持
 * @author hh
 * @date 2009/12/3 pm
 */
public class NumericHelper {

	private NumericHelper(){
	}
	
	 /**金额为分的格式 */  
    public static final String CURRENCY_FEN_REGEX = "\\-?[0-9]+";  
      
    /**  
     * 将分为单位的转换为元并返回金额格式的字符串 （除100） 
     *  
     * @param amount 
     * @return 
     * @throws Exception  
     */  
    public static String changeF2Y(Long amount) throws Exception{  
        if(!amount.toString().matches(CURRENCY_FEN_REGEX)) {  
            throw new Exception("金额格式有误");  
        }  
          
        int flag = 0;  
        String amString = amount.toString();  
        if(amString.charAt(0)=='-'){  
            flag = 1;  
            amString = amString.substring(1);  
        }  
        StringBuffer result = new StringBuffer();  
        if(amString.length()==1){  
            result.append("0.0").append(amString);  
        }else if(amString.length() == 2){  
            result.append("0.").append(amString);  
        }else{  
            String intString = amString.substring(0,amString.length()-2);  
            for(int i=1; i<=intString.length();i++){  
                if( (i-1)%3 == 0 && i !=1){  
                    result.append(",");  
                }  
                result.append(intString.substring(intString.length()-i,intString.length()-i+1));  
            }  
            result.reverse().append(".").append(amString.substring(amString.length()-2));  
        }  
        if(flag == 1){  
            return "-"+result.toString();  
        }else{  
            return result.toString();  
        }  
    }  
      
    /** 
     * 将分为单位的转换为元 （除100） 
     *  
     * @param amount 
     * @return 
     * @throws Exception  
     */  
    public static String changeF2Y(String amount) throws Exception{  
        if(!amount.matches(CURRENCY_FEN_REGEX)) {  
            throw new Exception("金额格式有误");  
        }  
        return BigDecimal.valueOf(Long.valueOf(amount)).divide(new BigDecimal(100)).toString();  
    }  
      
    /**  
     * 将元为单位的转换为分 （乘100） 
     *  
     * @param amount 
     * @return 
     */  
    public static String changeY2F(Long amount){  
        return BigDecimal.valueOf(amount).multiply(new BigDecimal(100)).toString();  
    }  
      
    /**  
     * 将元为单位的转换为分 替换小数点，支持以逗号区分的金额 
     *  
     * @param amount 
     * @return 
     */  
    public static String changeY2F(String amount){  
        String currency =  amount.replaceAll("\\$|\\￥|\\,", "");  //处理包含, ￥ 或者$的金额  
        int index = currency.indexOf(".");  
        int length = currency.length();  
        Long amLong = 0l;  
        if(index == -1){  
            amLong = Long.valueOf(currency+"00");  
        }else if(length - index >= 3){  
            amLong = Long.valueOf((currency.substring(0, index+3)).replace(".", ""));  
        }else if(length - index == 2){  
            amLong = Long.valueOf((currency.substring(0, index+2)).replace(".", "")+0);  
        }else{  
            amLong = Long.valueOf((currency.substring(0, index+1)).replace(".", "")+"00");  
        }  
        return amLong.toString();  
    }  
      
    public static void main(String[] args) {  
        System.out.println(changeY2F("1.33"));  
        try {
			System.out.println(changeF2Y("1323332"));
		} catch (Exception e) {
			e.printStackTrace();
		}
          
    }  
}