선이의 一生牛步行

  <listener>
  	<display-name>ContextLoader</display-name>
  	<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
  </listener>

<?xml version="1.0" encoding="UTF-8"?>

<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xmlns:aop="http://www.springframework.org/schema/aop"
	xmlns:context="http://www.springframework.org/schema/context"
	xmlns:tx="http://www.springframework.org/schema/tx"
	xmlns:util="http://www.springframework.org/schema/util"
	xsi:schemaLocation="http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.0.xsd
		http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
		http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-3.0.xsd
		http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.0.xsd">

<bean id="FirstMessage" class="com.acme.FirstMessage" />

</beans>

public static String addComma(int intValue) {
    return addComma(String.valueOf(intValue));
}

public static String addComma(double doubleValue) {
    return addComma(String.valueOf(doubleValue));
}

public static String addComma(String strValue) {
    if( strValue == null || "".equals(strValue) ) {
        return "";
    }
    return strValue;
}

package com.acme.util;

public class MoneyFormat {

	public static String addComma(int intValue) {
		return addComma(String.valueOf(intValue));
	}

	public static String addComma(double doubleValue) {
		return addComma(String.valueOf(doubleValue));
	}

	public static String addComma(String strValue) {
		if( strValue == null || "".equals(strValue) ) {
			return "";
		}

		StringBuilder retValue = new StringBuilder();
		int isMinus = extractSignPart(strValue, retValue);
		int pointIdx = extractDecimal(strValue, retValue, isMinus);
		return extractBelow(strValue, retValue, pointIdx);
	}

	private static int extractSignPart(String strValue, StringBuilder retValue) {
		int isMinus = (strValue.charAt(0) == '-') ? 1 : 0;
		String signPart = (isMinus == 1) ? "-" : "";
		retValue.append(signPart);
		return isMinus;
	}

	private static int extractDecimal(String strValue, StringBuilder retValue,
			int isSign) {
		int pointIdx = strValue.indexOf('.');
		String intPart = (pointIdx == -1) ? strValue.substring(isSign)
				: strValue.substring(isSign, pointIdx);
		retValue.append(putComma(intPart));
		return pointIdx;
	}

	private static String extractBelow(String strValue, StringBuilder retValue,
			int pointIdx) {
		String belowPart = (pointIdx == -1) ? "" : strValue.substring(pointIdx);
		retValue.append(belowPart);
		return retValue.toString();
	}

	private static Object putComma(String intPart) {

		StringBuilder sb = new StringBuilder();
		int hop = 0;
		for (int idx = intPart.length() - 1; idx >= 0; idx--, hop++) {
			if (hop > 0 && hop % 3 == 0) {
				sb.insert(0, ",");
			}
			sb.insert(0, intPart.charAt(idx));
		}

		return sb.toString();
	}
}

package com.acme.test;

import org.junit.Assert;

import org.junit.runner.JUnitCore;
import org.junit.Test;

import com.acme.util.MoneyFormat;

public class MoneyFormatTest {

	@Test
	public void moneyFormat() {
		Assert.assertEquals( MoneyFormat.addComma(null), "" );
		Assert.assertEquals( MoneyFormat.addComma(""), "" );
		Assert.assertEquals(MoneyFormat.addComma(10), "10");
		Assert.assertEquals(MoneyFormat.addComma(100), "100");
		Assert.assertEquals(MoneyFormat.addComma(123), "123");
		Assert.assertEquals(MoneyFormat.addComma(123.45), "123.45");
		Assert.assertEquals(MoneyFormat.addComma(1234), "1,234");
		Assert.assertEquals(MoneyFormat.addComma(-12345), "-12,345");
		Assert.assertEquals(MoneyFormat.addComma(-12345.67), "-12,345.67");
		Assert.assertEquals(MoneyFormat.addComma(123456.78), "123,456.78");
	}
	
	public static void main(String[] args) {
		JUnitCore.main("com.acme.test.MoneyFormatTest");
	}
}