如何取前一个月的时间

给你一个很有用的时间类import java.util.Calendar;
import java.util.Date;
import java.text.*;
public class DateDealWith
{
  public DateDealWith(){
  }
    //取得系统当前时间,格式为yyyy-mm-dd
  public String getCurrentDate(){
        Calendar rightNow = Calendar.getInstance();
        int year=rightNow.get(rightNow.YEAR);
        int month=rightNow.get(rightNow.MONTH)+1;
        int day=rightNow.get(rightNow.DATE);
        return year+"-"+month+"-"+day;
  }
      //取得系统当前时间,格式为yyyy年mm月dd日
  public String getCurrentDate1(){
        Calendar rightNow = Calendar.getInstance();
        int year=rightNow.get(rightNow.YEAR);
        int month=rightNow.get(rightNow.MONTH)+1;
        int day=rightNow.get(rightNow.DATE);
        return year+"年"+month+"月"+day+"日";
  }
    //取得系统当前时间前n个月的相对应的一天
  public String getNMonthBeforeCurrentDay(int n){
      Calendar c = Calendar.getInstance();
      c.add(c.MONTH,-n);
      return ""+c.get(c.YEAR)+"-"+(c.get(c.MONTH)+1)+"-"+c.get(c.DATE);  }
    //取得系统当前时间后n个月的相对应的一天
  public String getNMonthAfterCurrentDay(int n){
      Calendar c = Calendar.getInstance();
      c.add(c.MONTH,n);
      return ""+c.get(c.YEAR)+"-"+(c.get(c.MONTH)+1)+"-"+c.get(c.DATE);  }

      //取得系统当前时间前n天,格式为yyyy-mm-dd
  public String getNDayBeforeCurrentDate(int n){
        Calendar c = Calendar.getInstance();
        c.add(c.DAY_OF_MONTH,-n);
       return ""+c.get(c.YEAR)+"-"+(c.get(c.MONTH)+1)+"-"+c.get(c.DATE);
  }
        //取得系统当前时间后n天,格式为yyyy-mm-dd
  public String getNDayAfterCurrentDate(int n){
        Calendar c = Calendar.getInstance();
        c.add(c.DAY_OF_MONTH,n);
       return ""+c.get(c.YEAR)+"-"+(c.get(c.MONTH)+1)+"-"+c.get(c.DATE);
  }
  //---------------------------------------------------------------------
      //取过去一个时间对应的系统当年的一天
  public String getCurrentDateAfterPastDate(String sPastDate){
    if(sPastDate!=null && !sPastDate.equals("")){
      Date date=switchStringToDate(sPastDate);
      Calendar c = Calendar.getInstance();
      c.setTime(date);
      int iPastYear=c.get(c.YEAR);
      Calendar c1 = Calendar.getInstance();
      int iCurrentYear=c1.get(c1.YEAR);
      c.add(c.YEAR,iCurrentYear-iPastYear);
      return ""+c.get(c.YEAR)+"-"+(c.get(c.MONTH)+1)+"-"+c.get(c.DATE);
    }else{
      return null;
    }
  }
  //-----------------------------------------------------------------
  //将一个日期字符串转化成日期
  public Date switchStringToDate(String sDate){
     Date date=null;
     try{
       SimpleDateFormat df=new SimpleDateFormat("yyyy-MM-dd");
       date=df.parse(sDate);

     }catch(Exception e){
       System.out.println("日期转换失败:"+e.getMessage());
     }
     return date;
  }  //输入两个字符串型的日期，比较两者的大小
  public boolean compareTwoDateBigOrSmall(String fromDate,String toDate){
     Date dateFrom = this.switchStringToDate(fromDate);
     Date dateTo = this.switchStringToDate(toDate);
     if(dateFrom.before(dateTo)){
        return true;
     }else{
        return false;
     }
  }

  //将一个日期字符串转化成Calendar
  public Calendar switchStringToCalendar(String sDate){
      Date date = switchStringToDate(sDate);
      Calendar c = Calendar.getInstance();
      c.setTime(date);
      return c;
  }
//将一个日期转化成Calendar
  public Calendar switchStringToCalendar(Date date){
      Calendar c = Calendar.getInstance();
      c.setTime(date);
      return c;
  }
//------------------------------------------------------------------------
    //取得某个时间前n个月的相对应的一天
  public String getNMonthBeforeOneDay(String sDate,int n){
      Calendar c = switchStringToCalendar(sDate);
      c.add(c.MONTH,-n);
      return ""+c.get(c.YEAR)+"-"+(c.get(c.MONTH)+1)+"-"+c.get(c.DATE);  }
    //取得某个时间后n个月的相对应的一天
  public String getNMonthAfterOneDay(String sDate,int n){
      Calendar c = switchStringToCalendar(sDate);
      c.add(c.MONTH,n);
      return ""+c.get(c.YEAR)+"-"+(c.get(c.MONTH)+1)+"-"+c.get(c.DATE);  }

      //取得某个时间前n天,格式为yyyy-mm-dd
  public String getNDayBeforeOneDate(String sDate,int n){
        Calendar c = switchStringToCalendar(sDate);
        c.add(c.DAY_OF_MONTH,-n);
       return ""+c.get(c.YEAR)+"-"+(c.get(c.MONTH)+1)+"-"+c.get(c.DATE);
  }
        //取得某个时间后n天,格式为yyyy-mm-dd
  public String getNDayAfterOneDate(String sDate,int n){
        Calendar c = switchStringToCalendar(sDate);
        c.add(c.DAY_OF_MONTH,n);
       return ""+c.get(c.YEAR)+"-"+(c.get(c.MONTH)+1)+"-"+c.get(c.DATE);
  }
  //判断系统当前时间是不是润年
  public boolean isRunNian(){
   java.util.Calendar rightNow = java.util.Calendar.getInstance();
   int year=rightNow.get(rightNow.YEAR);
   if(0==year%4 && (year%100!=0 || year%400==0)){
      return true;
   }else{
      return false;
   }  }
}

或者
java.util.Date xx=new java.util.Date();
long i=xx.getTime();
i=i-30*24*60*60*1000;
java.util.Date yy=new java.util.Date(i);

to:mtou(逆风)
你的方法只能取30天前的时间吧？

java.util.Date xx=new java.util.Date();
myyear=xx.getYear();
mymonth=xx.getMonth();
myday=xx.day();
if(mymonth==1)
{
  xx.setYear(myyear-1);
  xx.setMonth(12)
}
else
  xx.setMonth(mymonth-1)l

to: flymoods(放飞心情
你的方法我试了一下，好象还是有点问题：如果是20030331
它的前一个月的时间我要求是20030228
但是得到的结果是：20030303

public String getadd_month(String s, int i)
    {
        String s1 = "";
        String s2 = "";
        try
        {
            SimpleDateFormat simpledateformat = new SimpleDateFormat("yyyy-MM-dd");
            java.util.Date date = new java.util.Date();
            String s3;
            if(s.trim().compareTo("") == 0)
                s3 = simpledateformat.format(date);
            else
                s3 = s;
            int j = (new Integer(s3.substring(0, 4))).intValue();
            int k = (new Integer(s3.substring(5, 7))).intValue();
            int l = (new Integer(s3.substring(8, 10))).intValue();
            GregorianCalendar gregoriancalendar = new GregorianCalendar(j, k, l);
            gregoriancalendar.add(2, i - 1);
            java.util.Date date1 = gregoriancalendar.getTime();
            s1 = simpledateformat.format(date1);
        }
        catch(Exception exception)
        {
            System.out.print("trun month error" + exception.getMessage());
        }
        return s1;
    }

调试易

如何取前一个月的时间

解决方案 »