【总结文之一】1.14更新,自己写的一个格式化输出时间的JSP标签

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javaWeb开发

JSP 正则表达式 Web XML SUN

在写Web程序中，往往要处理大量的时间日期显示的工作，一个灵活的格式化输出日期的工具必不可少。之前在网上找了好一会儿，没找到满意的，苦恼不已。索性，自己写个算了。

在这里跟大家共享。

这个是1.13的有错误的代码：

package cn.lhx.taglib.toolkit;

import java.util.Calendar;
import java.util.Date;
import java.util.HashMap;
import java.util.Map;
import java.util.regex.Pattern;

public class TimeFunction {
	private final static String wtb_en[] = { "am", "pm", "monday", "tuesday",
			"wednesday", "thursday", "friday", "saturday", "sunday", "january",
			"february", "march", "april", "may", "june", "july", "august",
			"september", "october", "november", "december", "gmt", "ut", "utc",
			"est", "edt", "cst", "cdt", "mst", "mdt", "pst", "pdt" };
	private final static String wtb_cn[] = { "上午", "下午", "星期一", "星期二", "星期三",
			"星期四", "星期五", "星期六", "星期天", "一月", "二月", "三月", "四月", "五月", "六月",
			"七月", "八月", "九月", "十月", "十一月", "十二月", "gmt", "ut", "utc", "est",
			"edt", "cst", "cdt", "mst", "mdt", "pst", "pdt" };
	//profile缓存
	private final static Map<Date, Map<String, String>> proBuf=new HashMap<Date, Map<String,String>>(10);
	

	private final static Map<String,String> init(Date date){
		Map<String,String> profile =(HashMap<String, String>)proBuf.get(date);
		//查找缓存，有解析过的就直接返回
		if(profile!=null)return profile;
		date.toString();
		//new 一个Map
		profile=new HashMap<String, String>();
		//解析日期
		Calendar calendar=Calendar.getInstance();
		calendar.setTime(date);
		int year=calendar.get(Calendar.YEAR);
		int month=calendar.get(Calendar.MONTH);//月重0开始
		int day=calendar.get(Calendar.DAY_OF_MONTH);
		int weekDay=calendar.get(Calendar.DAY_OF_WEEK);
		weekDay=(weekDay==Calendar.SUNDAY)? 7:(weekDay-1);
		int hour=calendar.get(Calendar.HOUR_OF_DAY);
		int minute=calendar.get(Calendar.MINUTE);
		int am_pm=calendar.get(Calendar.AM_PM);//0 AM 1 PM
		//年
		profile.put("%Yc", year+"年");
		profile.put("%Ye", year+"");
		profile.put("%Y", year+"");
		//月
		profile.put("%Mc", wtb_cn[month+9]);
		profile.put("%Me", wtb_en[month+9]);
		profile.put("%M", (month+1)+"");
		//日
		profile.put("%D",day+"");
		String dayDix="th";
		//day调整1st、2nd、3rd
		dayDix=(day%10==1?"st":(day%10==2?"nd":(day%10==3?"rd":dayDix)));
		profile.put("%De",day+dayDix);
		profile.put("%Dc",day+"日");
		//星期
		profile.put("%W",weekDay+"");
		profile.put("%We",wtb_en[weekDay+1]);
		profile.put("%Wc",wtb_cn[weekDay+1]);
		//时间
		int hour12=hour>12?hour-12:hour;//转换成12小时格式
		profile.put("%T12",(hour12)+":"+minute);
		profile.put("%T24",hour+":"+minute);
		//上下午
		profile.put("%N",wtb_en[am_pm]);
		profile.put("%Ne",wtb_en[am_pm]);
		profile.put("%Nc",wtb_cn[am_pm]);
		//放入缓存
		proBuf.put(date, profile);
		return profile;
		}

	/**
	 * 将日期转换成格式化字符串
	 * @param str 带有给事标识符的字符串
	 * @param date 日期对象
	 *  @return
	 * %Y[?]:年<br/>
	 * %M[?]:月<br/>
	 * %D[?]:日<br/>
	 * %T[12|24]:时间，12表示十二小时制,24表示...
	 * <br/>详细参数列表
	 * <table border=1px>
	 * 	<tr><td>格式符</td><td>形式,示例</td><td>格式符</td><td>形式,示例</td></tr>
	 * <tr><td>%Y</td><td>数字,2010</td><td>%D</td><td>日,数字</td></tr>
	 * <tr><td>%Yc</td><td>数字+年,2010年</td><td>%Dc</td><td>数字+日,23日</td></tr>
	 * <tr><td>%Ye</td><td>数字,2009</td><td>%De</td><td>数字+th,23th</td></tr>
	 * <tr><td>%M</td><td>数字,12</td><td>%W</td><td>星期，数字,7</td></tr>
	 * <tr><td>%Mc</td><td>中文+月,十二月</td><td>%We</td><td>英文，sunday</td></tr>
	 * <tr><td>%Me</td><td>英文,dec</td><td>%Wc</td><td>中文,星期天</td></tr>
	 * <tr><td>%N</td><td>英文,am</td><td>%Ne</td><td>中文,星期天</td></tr>
	 * <tr><td>%Nc</td><td>中文,上午</td><td>%T[12|24]</td><td>数字,12:30</td></tr>
	 * </table>
	 * Example:<br/>
	 * str="今天是%Yc，%Mc,%Dc,%Wc"<br/>
	 * 输出:今天是2010年，一月,13日,星期三<br/>
	 * str=""今天是%Yc，%Me,%De,%We""<br/>
	 * 输出:今天是2010年，january,13rd,wednesday<br/>
	 */
	public static String getFormateTimeStr(String str,Date date){
		//获得参数
		Map<String, String> profile=init(date);
		//正则解析
		java.util.regex.Pattern pattern=Pattern.compile("\\%[M,D,Y,T,N,W]([ce~]|[124]{0,2})");
		java.util.regex.Matcher matcher=pattern.matcher(str);
		boolean isFind=matcher.find();
		StringBuffer sb=new StringBuffer();
		while (isFind) {
			String findStr=matcher.group();
//			System.out.println("findStr =="+findStr);
//			System.out.println("group1== "+matcher.group(1)); 
//			System.out.println("StartIndex== "+matcher.start());
//			System.out.println("EndIndex== "+matcher.end());
			if(profile.get(findStr)!=null){
				//如果找到了就用profile里格式化串替换标记
				matcher.appendReplacement(sb, profile.get(findStr));
			}
			isFind=matcher.find();
		}
		matcher.appendTail(sb);
		return sb.toString();
	}
	
	//测试
	public static void main(String[] args) {
		Date date=new Date();
		System.out.println(TimeFunction.getFormateTimeStr("今天是%Yc，%Mc,%Dc,%Wc", date));
		System.out.println(TimeFunction.getFormateTimeStr("今天是%Yc，%Me,%De,%We", date));
	}
}

使用到了java正则表达式库，和HashMap,其他的看代码应该不用过多解释了。

去掉代码中的一些system.out，可以观察解析过程。

1.14：修正了缓存的错误实现，以下是更新后的TimeFunction中的init方法，和静态量，对照旧版本，你会发现旧版本存在严重问题

    //缓存容量
    private final static int maxCapacity = 10;
    //profile缓存
    private final static Map<Date, Map<String, String>> proBuf = new HashMap<Date, Map<String, String>>(maxCapacity);

   private final static Map<String, String> init(Date date) {
        //查找缓存
        Date lastDate = date;
        for (Iterator it = proBuf.keySet().iterator(); it.hasNext();) {
            lastDate = (Date) it.next();
            if (lastDate.equals(date)) {
                return proBuf.get(lastDate);
            }
        }
        //缓存中没有找到，new 一个Map
        Map<String, String> profile = new HashMap<String, String>();
        //解析日期
        Calendar calendar = Calendar.getInstance();
        calendar.setTime(date);
        int year = calendar.get(Calendar.YEAR);
        int month = calendar.get(Calendar.MONTH);//月重0开始
        int day = calendar.get(Calendar.DAY_OF_MONTH);
        int weekDay = calendar.get(Calendar.DAY_OF_WEEK);
        weekDay = (weekDay == Calendar.SUNDAY) ? 7 : (weekDay - 1);
        int hour = calendar.get(Calendar.HOUR_OF_DAY);
        int minute = calendar.get(Calendar.MINUTE);
        int am_pm = calendar.get(Calendar.AM_PM);//0 AM 1 PM
        //年
        profile.put("%Yc", year + "年");
        profile.put("%Ye", year + "");
        profile.put("%Y", year + "");
        //月
        profile.put("%Mc", wtb_cn[month + 9]);
        profile.put("%Me", wtb_en[month + 9]);
        profile.put("%M", (month + 1) + "");
        //日
        profile.put("%D", day + "");
        String dayDix = "th";
        //day调整1st、2nd、3rd
        dayDix = (day % 10 == 1 ? "st" : (day % 10 == 2 ? "nd" : (day % 10 == 3 ? "rd" : dayDix)));
        profile.put("%De", day + dayDix);
        profile.put("%Dc", day + "日");
        //星期
        profile.put("%W", weekDay + "");
        profile.put("%We", wtb_en[weekDay + 1]);
        profile.put("%Wc", wtb_cn[weekDay + 1]);
        //时间
        int hour12 = hour > 12 ? hour - 12 : hour;//转换成12小时格式
        profile.put("%T12", (hour12) + ":" + minute);
        profile.put("%T24", hour + ":" + minute);
        //上下午
        profile.put("%N", wtb_en[am_pm]);
        profile.put("%Ne", wtb_en[am_pm]);
        profile.put("%Nc", wtb_cn[am_pm]);

        if (proBuf.size() < maxCapacity) {
            //放入缓存
            proBuf.put(date, profile);
        } else {
            //移除最旧的日期profile
            proBuf.remove(lastDate);
            proBuf.put(date, profile);
        }
//        System.out.println("proBuf.size= "+proBuf.size());
        return profile;
    }

标签定义文件：timefunction.tld

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

<taglib xmlns="http://java.sun.com/xml/ns/j2ee"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-jsptaglibrary_2_0.xsd"
  version="2.0">
 <description>MyTag 1.0</description>
 <tlib-version>1.0</tlib-version>
 <jsp-version>1.2</jsp-version>
 <short-name>tmf</short-name>
 <uri>/timefunction</uri>
 
 <function>
    <description>
    
    </description>
    <name>getFormateTimeStr</name>
    <function-class>cn.lhx.taglib.toolkit.TimeFunction</function-class>
    <function-signature>java.lang.String getFormateTimeStr(java.lang.String,java.util.Date)</function-signature>
    <example>
     
    </example>
  </function>
</taglib>

标签的使用：

1.在web.xml中加入：

	<taglib>
		<taglib-uri>/timefunction</taglib-uri>
		<taglib-location>/WEB-INF/timefunction.tld</taglib-location>
	</taglib>

2.在jsp页面中加入：

<%@ taglib uri="/timefunction" prefix="tmf"%>

3.在想要格式转换的地方加入自己的字符串，实例：

<div class="postDate">
							${tmf:getFormateTimeStr(
							'<p> %Mc </p>
							<p class=day>%D</p>
							<p> %Y</p>' 
							,article.postTime) }
							</div>

OK，不出意外的话，你应该看到结果了