Date获取时间段

/**
 * 
 */
package com.chinabase.common.util;

/**
 * @author yuanji
 * @created on:Sep 19, 2008
 */
import java.sql.Timestamp;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;

public class TimeFormat {

    /**
     * 获得当前时间精确到毫秒
     * 
     * @return
     */
    public static String getTimestamp() {
        Timestamp timestamp = new Timestamp(System.currentTimeMillis());
        return timestamp.toString();
    }

    /**
     * 生成文件夹名
     * 
     * @return
     */
    public static String toFileName() {
        return getTimestamp().replaceAll("-| |:|\.", "");
    }

    /**
     * 获得年-月-日
     * 
     * @return
     */
    public static String getDate() {
        return getTimestamp().substring(0, 10);
    }

    /**
     * 
     * @return 获取当月的第一天
     */
    public static String getFirstMonthDay(){
        SimpleDateFormat df1 = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");      
           Date date = new Date();
           Date da = new Date(date.getYear(),date.getMonth(),01);    
           Timestamp startTime=Timestamp.valueOf(df1.format(da));
           return startTime.toLocaleString();
    }
    //获取当月的最后-天
    public static String  getLastDayOfMonth()   {   
        Calendar cal = Calendar.getInstance(); 
        SimpleDateFormat datef=new SimpleDateFormat("yyyy-MM-dd");
                     cal.set( Calendar.DATE, 1 );
                     cal.roll(Calendar.DATE, - 1 );
                     Date endTime=cal.getTime();
                     String endTime1=datef.format(endTime)+" 23:59:59";
                    return endTime1;
}  
    public static String getTime() {
        return getTimestamp().substring(11);
    }

    public static void main(String[] args) {
        System.out.println(TimeFormat.getTimestamp());
        System.out.println(TimeFormat.toFileName());
        System.out.println(TimeFormat.getDate());
        System.out.println(getTime());
        System.out.println(getTime().substring(0, 8));
        System.out.println(getLastDayOfMonth());
        System.out.println(getFirstMonthDay());
    }
}