返回不同时间的字符串

package com.lg.util;

import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;


/**
*   根据当前时间返回不同时间点的字符串时间
*  
* @author  BaiFuyou
* @date: Jun 22, 2010 10:29:35 PM
*/
public class BeforeDay {

/**
*
* @return 格式化好的当前日期前一天的字符串时间：yyyy:MM:dd:HH:mm:ss
*/
public static String getBeforDay(){
Calendar cal =  Calendar.getInstance();
int year = cal.get(Calendar.YEAR);
int month = cal.get(Calendar.MONTH);
int day = cal.get(Calendar.DAY_OF_MONTH);
int hour =cal.get(Calendar.HOUR_OF_DAY);
int minute = cal.get(Calendar.MINUTE);
int second = cal.get(Calendar.SECOND);
cal.set(year, month, day, hour-24, minute, second);
Date date = cal.getTime();
SimpleDateFormat sdf = new SimpleDateFormat("yyyy:MM:dd:HH:mm:ss");
return sdf.format(date);
}
/**
*
* @return  返回当前日期前十个小时的字符串时间：yyyy:MM:dd:HH:mm:ss
*/
public static String getBeforeDayPlus10Hour(){
Calendar cal =  Calendar.getInstance();
int year = cal.get(Calendar.YEAR);
int month = cal.get(Calendar.MONTH);
int day = cal.get(Calendar.DAY_OF_MONTH);
int hour =cal.get(Calendar.HOUR_OF_DAY);
int minute = cal.get(Calendar.MINUTE);
int second = cal.get(Calendar.SECOND);
cal.set(year, month, day, hour-10, minute, second);
Date date = cal.getTime();
SimpleDateFormat sdf = new SimpleDateFormat("yyyy:MM:dd:HH:mm:ss");
return sdf.format(date);
}
/**
*
* @return 返回当前时间前12个小时的字符串时间：yyyy:MM:dd:HH:mm:ss
*/
public static String getBeforeDayPlus12Hour(){
Calendar cal =  Calendar.getInstance();
int year = cal.get(Calendar.YEAR);
int month = cal.get(Calendar.MONTH);
int day = cal.get(Calendar.DAY_OF_MONTH);
int hour =cal.get(Calendar.HOUR_OF_DAY);
int minute = cal.get(Calendar.MINUTE);
int second = cal.get(Calendar.SECOND);
cal.set(year, month, day, hour-12, minute, second);
Date date = cal.getTime();
SimpleDateFormat sdf = new SimpleDateFormat("yyyy:MM:dd:HH:mm:ss");
return sdf.format(date);
}
/**
*
* @return 返回当前时间前1小时的字符串时间：yyyy:MM:dd:HH:mm:ss
*
* 用作测试，实际使用会死机
*/
public static String getBeforeDayPlus1Hour(){
Calendar cal =  Calendar.getInstance();
int year = cal.get(Calendar.YEAR);
int month = cal.get(Calendar.MONTH);
int day = cal.get(Calendar.DAY_OF_MONTH);
int hour =cal.get(Calendar.HOUR_OF_DAY);
int minute = cal.get(Calendar.MINUTE);
int second = cal.get(Calendar.SECOND);
cal.set(year, month, day, hour-1, minute, second);
Date date = cal.getTime();
SimpleDateFormat sdf = new SimpleDateFormat("yyyy:MM:dd:HH:mm:ss");
return sdf.format(date);
}
/**
*
* @return 返回当前时间的字符串时间：yyyy:MM:dd:HH:mm:ss
*/
public static String getNowDate()
{
Calendar cal =  Calendar.getInstance();
int year = cal.get(Calendar.YEAR);
int month = cal.get(Calendar.MONTH);
int day = cal.get(Calendar.DAY_OF_MONTH);
int hour =cal.get(Calendar.HOUR_OF_DAY);
int minute = cal.get(Calendar.MINUTE);
int second = cal.get(Calendar.SECOND);
cal.set(year, month, day, hour, minute, second);
Date date = cal.getTime();
SimpleDateFormat sdf = new SimpleDateFormat("yyyy:MM:dd:HH:mm:ss");
return sdf.format(date);
}

}