java获取某月最后一天 java获取某个月的最后一天

package com.printxls.test; 


 import java.text.SimpleDateFormat; 

 import java.util.Calendar; 

 import java.util.Date; 


 public class DateFormatTest { 


     public static void main(String[] args) { 

         String datadate = "2013-01-12"; 

         DateFormatTest test = new DateFormatTest(); 

         try { 

             System.out.println("第一天=" + test.getFirstDay(datadate)); 

             System.out.println("最后一天=" + test.getLastDay(datadate)); 

         } catch (Exception e) { 

             e.printStackTrace(); 

         } 

     } 

      

     public String getLastDay(String datadate)throws Exception{ 

         Date date = null; 

         String day_last = null; 

         SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd"); 

         date = format.parse(datadate); 

          

         //创建日历 

         Calendar calendar = Calendar.getInstance(); 

         calendar.setTime(date); 

         calendar.add(Calendar.MONTH, 1);    //加一个月 

         calendar.set(Calendar.DATE, 1);     //设置为该月第一天 

         calendar.add(Calendar.DATE, -1);    //再减一天即为上个月最后一天 

         day_last = format.format(calendar.getTime()); 

         return day_last; 

     } 

      

     public String getFirstDay(String datadate)throws Exception{ 

         Date date = null; 

         String day_first = null; 

         SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd"); 

         date = format.parse(datadate); 

          

         //创建日历 

         Calendar calendar = Calendar.getInstance(); 

         calendar.setTime(date); 

         calendar.set(Calendar.DAY_OF_MONTH, 1); 

         day_first = format.format(calendar.getTime()); 

         return day_first; 

     } 

 }