numberutility.java

采用JAVA开发

/**
 * $RCSfile: NumberUtility.java,v $
 * $Revision: 1.1.1.1 $
 * $Date: 2004/01/07 05:06:28 $
 *
 * Copyright (C) 2003 ICSS, Inc. All rights reserved.
 *
 * This software is the proprietary information of ICSS, Inc.
 * Use is subject to license terms.
 */
package com.gctech.misc.util;

import java.text.DecimalFormat;

/**
 * <p>Title: OA系统</p>
 * <p>Description: 数字常用的方法</p>
 * <p>Copyright: Copyright (c) 2002-12-5</p>
 * <p>Company: 中软远东国际</p>
 *
 * @version 1.0
 * @author  Andy
 */
public class NumberUtility {

    /**
     * 格式化double类型数字 保留decimalDigits位小数
     *
     * @param number 要格式化的double数字
     * @param decimalDigits 保留小数位数
     * @return java.lang.String
     */
    public static String formatNumber(double number, int decimalDigits) {
        String result;
        if (decimalDigits < 0)
            throw new IllegalArgumentException("小数位数decimalDigits不能为负。");
        if (decimalDigits == 0) {
            result = String.valueOf(Math.round(number));
        }
        else {
            StringBuffer format = new StringBuffer("0.");
            long l = 1;
            for (int i = 0; i < decimalDigits; i++) {
                format.append("0");
                l *= 10;
            }

            StringBuffer d = new StringBuffer();
            d.append(l).append(".");
            for (int i = 0; i < decimalDigits; i++) {
                d.append("0");
            }
            d.append("d");

            DecimalFormat decimalFormat = new DecimalFormat(format.toString());
            result = decimalFormat.format(Math.round(number * l) / Double.parseDouble(d.toString()));
        }

        return result;
    }

    /**
     * 格式化float类型数字 保留decimalDigits位小数
     *
     * @param number 要格式化的float数字
     * @param decimalDigits 保留小数位数
     * @return java.lang.String
     */
    public static String formatNumber(float number, int decimalDigits) {
        String result;
        if (decimalDigits < 0)
            throw new IllegalArgumentException("小数位数decimalDigits不能为负。");
        if (decimalDigits == 0) {
            result = String.valueOf(Math.round(number));
        }
        else {
            StringBuffer format = new StringBuffer("0.");
            long l = 1;
            for (int i = 0; i < decimalDigits; i++) {
                format.append("0");
                l *= 10;
            }

            StringBuffer d = new StringBuffer();
            d.append(l).append(".");
            for (int i = 0; i < decimalDigits; i++) {
                d.append("0");
            }
            d.append("d");

            DecimalFormat decimalFormat = new DecimalFormat(format.toString());
            result = decimalFormat.format(Math.round(number * l) / Double.parseDouble(d.toString()));
        }

        return result;

    }

    /**
     * 格式化String类型数字 保留decimalDigits位小数
     *
     * @param number 要格式化的String数字
     * @param decimalDigits 保留小数位数
     * @return java.lang.String
     */
    public static String formatNumber(String number, int decimalDigits) {
        return formatNumber(Double.parseDouble(number), decimalDigits);
    }

    public static void main(String args[]) {
        System.out.println(Long.MAX_VALUE);
        System.out.println("NumberUtility.formatNumber(12.2345, 3) = " + formatNumber(12.2345, 3));
        System.out.println("NumberUtility.formatNumber(12.2345, 2) = " + formatNumber(12.2345, 2));
        System.out.println("NumberUtility.formatNumber(\"12.2345\", 3) = " + formatNumber("12.2345", 3));
        System.out.println("NumberUtility.formatNumber(\"12.2345\", 2) = " + formatNumber("12.2345", 2));

        System.out.println("将会出错：");
        System.out.println(formatNumber(12.2345, -1));

    }
}