数字格式化工具类

/**
 * 数字格式化工具类.<br>
 */
public abstract class NumberUtils {
	/**
	 * 按指定的样式格式化数字.<br>
	 * 例如:
	 * <li><code>format(1,"#0.000")</code>,结果1.000
	 * <li><code>format(1.165686,"#0.000")</code>,结果1.166
	 * <li><code>format(0,"#0.00")</code>,结果0.00
	 * <li><code>format(0.2556,"#0.00%")</code>,结果25.56%
	 * <li><code>format(1,"#0%")</code>,结果100%
	 * @param d double
	 * @param pattern 格式化字符串. 如:#0.000(带三位小数点,四舍五入)
	 * @return
	 */
	public static String format(double d, String pattern) {
		DecimalFormat nf = new DecimalFormat(pattern);
		return nf.format(d);
	}

	/**
	 * {@link #format(double, String)}.
	 * @param doubleStr
	 * @param pattern
	 * @return
	 */
	public static String format(String doubleStr, String pattern) {
		double d = 0;
		try {
			d = Double.parseDouble(doubleStr);
		} catch (NumberFormatException e) {
			System.out.println("字符串转换成数字有异常!  doubleStr=" + doubleStr);
		}
		return format(d, pattern);
	}

	/**
	 * 和 {@link #format(double, String)}相似,区别在于返回值增加了一个html的空格字符(&nbsp;).
	 * @param d
	 * @param pattern
	 * @return 返回值增加了一个html格式的空格符(&nbsp;).
	 */
	public static String formatWithBlank(double d, String pattern) {
		return format(d, pattern) + "&nbsp;";
	}

	/**
	 * {@link #formatWithBlank(double, String)}
	 * @param doubleStr
	 * @param pattern
	 * @return
	 */
	public static String formatWithBlank(String doubleStr, String pattern) {
		double d = 0;
		try {
			d = Double.parseDouble(doubleStr);
		} catch (NumberFormatException e) {
			System.out.println("字符串转换成数字有异常!  doubleStr=" + doubleStr);
		}
		return formatWithBlank(d, pattern);
	}

	/**
	 * 给数字字符后增加一个html格式的空格符(&nbsp;);<br>
	 * 用途:在将html页面导出excel格式时,excel会默认将数字字符串转换成数字,这样会导致字符串前后的00被清掉.
	 * 调用此方法,增加了一个空格字符后,可以避免excel的自动转换. 如:1.200,excel会自动转换成1.2;
	 * 00012,excel会自动转换成12;
	 * @param numStr 数字字符串
	 * @return
	 */
	public static String addBlank(String numStr) {
		return numStr + "&nbsp;";
	}

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		double d = 1.165686;
		String result = NumberUtils.format(d, "#0.000");
		System.out.println("" + result);
		d = 1;
		result = NumberUtils.format(d, "#0.00%");
		System.out.println("" + result);
		d = 0;
		result = NumberUtils.format(d, "#0.0%");
		System.out.println("" + result);
		d = 0.2556;
		result = NumberUtils.format(d, "#0.00%");
		System.out.println("" + result);
		d = 1;
		result = NumberUtils.format(d, "#0%");
		System.out.println("" + result);
		System.out.println("-----------");
		System.out.println(NumberUtils.format("3.1415926", "#0.00%"));
	}

}