1，

package com.banksteel.openerp.common.vo;

import java.io.Serializable;

public class TimeIntervalVO implements Serializable {

    /**
     * 
     */
    private static final long serialVersionUID = -1568237892596588268L;
    private Long beginInMillis; // 设置时间当天的零点
    private Long endInMillis;  // 设置时间当天最后一秒
    private String beginInString; // 显示时间
    private String endInString; // 显示时间

    public Long getBeginInMillis() {
        return beginInMillis;
    }

    public void setBeginInMillis(Long beginInMillis) {
        this.beginInMillis = beginInMillis;
    }

    public Long getEndInMillis() {
        return endInMillis;
    }

    public void setEndInMillis(Long endInMillis) {
        this.endInMillis = endInMillis;
    }

    public String getBeginInString() {
        return beginInString;
    }

    public void setBeginInString(String beginInString) {
        this.beginInString = beginInString;
    }

    public String getEndInString() {
        return endInString;
    }

    public void setEndInString(String endInString) {
        this.endInString = endInString;
    }

    @Override
    public String toString() {
        return "TimeIntervalVO [beginInMillis=" + beginInMillis + ", endInMillis=" + endInMillis + ", beginInString="
                + beginInString + ", endInString=" + endInString + "]";
    }

}

　　2.

/*jadclipse*/// Decompiled by Jad v1.5.8g. Copyright 2001 Pavel Kouznetsov.

package cn.mysteel.util;

import java.text.SimpleDateFormat;
import java.util.Date;
import org.apache.commons.lang.StringUtils;

public class DateUtils
{

    public DateUtils()
    {
    }

    public static Date getDate(String s)
    {
        return getDate(s, null);
    }

    public static Date getJustDate(String s)
    {
        return getDate(s, "yyyy-MM-dd");
    }

    public static Date getDate(long date)
    {
        return getDate(date, null);
    }

    public static Date getJustDate(long date)
    {
        return getDate(date, "yyyy-MM-dd");
    }

    public static Date getDate(long date, String format)
    {
        if(StringUtils.isEmpty(format))
            format = "yyyy-MM-dd HH:mm:ss";
        return getDate(formatDate(new Date(date), format), format);
    }

    public static Date getDate(String s, String format)
    {
        Date date;
        try
        {
            if(StringUtils.isEmpty(format))
                format = "yyyy-MM-dd HH:mm:ss";
            date = (new SimpleDateFormat(format)).parse(s);
        }
        catch(Exception e)
        {
            date = new Date(0L);
        }
        return date;
    }

    public static String formatDate(long date, String format)
    {
        return formatDate(new Date(date), format);
    }

    public static String formatDate(long date)
    {
        return formatDate(new Date(date), null);
    }

    public static String formatJustDate(long date)
    {
        return formatDate(new Date(date), "yyyy-MM-dd");
    }

    public static String formatDate(Date date, String format)
    {
        if(StringUtils.isEmpty(format))
            format = "yyyy-MM-dd HH:mm:ss";
        return (new SimpleDateFormat(format)).format(date);
    }

    public static final String DATE_FROMAT1 = "yyyy-MM-dd";
    public static final String DATE_FROMAT2 = "yyyy-MM-dd HH:mm:ss";
}


/*
    DECOMPILATION REPORT

    Decompiled from: D:\eclipse\demo-maven\repository\cn\mysteel\shgl-core\1.0.0-SNAPSHOT\shgl-core-1.0.0-SNAPSHOT.jar
    Total time: 321 ms
    Jad reported messages/errors:
    Exit status: 0
    Caught exceptions:
*/

　　3

package com.banksteel.openerp.utils;

import java.util.Calendar;

import com.banksteel.openerp.common.vo.TimeIntervalVO;

import cn.mysteel.util.DateUtils;

/**
 * 时间工具类
 * 
 * @description:
 * @projectName:openerp-webapp
 * @className:TimeUtils.java
 * @createTime:2016年9月27日 下午4:02:40
 * @version 1.0
 */
public class TimeUtils {

    private TimeUtils() {
    };

    /**
     * 获取基准时间戳计算指定天数后的当天00:00:00.000至23:59:59.999时间戳区间
     * 
     * @param millis
     *            基准时间戳
     * @param dayOffset
     *            偏移天数，0表示当天，正数表示基准时间戳之后N天，负数反之
     * @createTime:2016年9月29日 下午5:19:40
     */
    public static TimeIntervalVO getMillisInterval(Long millis, int dayOffset) {
        TimeIntervalVO interval = new TimeIntervalVO();
        Calendar calendar = Calendar.getInstance();
        if (millis > 0) {
            calendar.setTime(DateUtils.getDate(millis, "yyyy-MM-dd"));
            calendar.add(Calendar.DATE, dayOffset);
            interval.setBeginInMillis(calendar.getTimeInMillis());
            interval.setBeginInString(DateUtils.formatDate(calendar.getTimeInMillis(), "yyyy-MM-dd HH:mm:ss.SSS"));
            interval.setEndInMillis(calendar.getTimeInMillis() + 86400000L - 1L);
            interval.setEndInString(
                    DateUtils.formatDate(calendar.getTimeInMillis() + 86400000L - 1L, "yyyy-MM-dd HH:mm:ss.SSS"));
        }
        return interval;
    }

}

　　4，java调用

public static void main(String[] args)
    {
        //当前时间
        Long currentTimeMillis = System.currentTimeMillis();
        // 30天前时间
        TimeIntervalVO beginTime = null;
        beginTime = TimeUtils.getMillisInterval(currentTimeMillis, -30);
        // 昨天时间
        TimeIntervalVO endTime = null;
        endTime = TimeUtils.getMillisInterval(currentTimeMillis, -1);
        System.out.println(beginTime.toString());
        System.out.println(endTime.toString());
        
    }

显示结果