Calendar c = Calendar.getInstance();
       //第一天
        c.set(Calendar.DATE,1);
       //最后一天
        int max = c.getActualMaximum(Calendar.DATE);
       c.set(Calendar.DATE,max);

------解决方案--------------------
用javascript控制一下啊  
function changDate(theStr){
  var returnStr;
var the5Str;
the5Str = theStr.subSring(5);
  if(theStr != null && theStr != ""){
   if(the5Str  != "02"){
     if(the5Str=="1"  || the5Str ="3" || the5Str ="5"|| the5Str ="7"||  
the5Str ="8"|| the5Str ="10" || the5Str ="12"){
      returnStr = theStr +"01-"+theStr+"30"
}else{
  returnStr = theStr +"01-"+theStr+"31"
}
    
}else{
 returnStr = theStr +"01-"+theStr+"29"
}
  
}

}

------解决方案--------------------
JScript code

var myDate= new Date();
var s1 = myDate.getYear() + "-" + myDate.getMonth + "-01";//第一天
var s2 = myDate.getYear() + "-" + myDate.getMonth + "-" + myDate.getDate();//最后一天

------解决方案--------------------
更正：
JScript code

var myDate= new Date();
var s1 = myDate.getYear() + "-" + myDate.getMonth() + "-01";//第一天
var s2 = myDate.getYear() + "-" + myDate.getMonth() + "-" + myDate.getDate();//最后一天

------解决方案--------------------
膜拜LZ

------解决方案--------------------
探讨

Java code
       Calendar c = Calendar.getInstance();
       //第一天
        c.set(Calendar.DATE,1);
       //最后一天
        int max = c.getActualMaximum(Calendar.DATE);
       c.set(Calendar.DATE,max);


------解决方案--------------------

Java code

package com.dm.sck.action.audit;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
public class A
{
    /**
      * 给一个日期，根据这个日期该日期月的起止日期
      * @throws ParseException 
      * 
      */
     public static void main(String[] args) throws ParseException
     {
     // TODO Auto-generated method stub
       
     
       
        Calendar cal = A.transStringToCalendar("yyyy-MM-dd", "2009-12-15");
        int maxdate = cal.getActualMaximum(Calendar.DATE);   
        int mindate = cal.getActualMinimum(Calendar.DATE);   
      
     
        cal.set(Calendar.DATE, maxdate);
        Date max = cal.getTime();
        
        String maxStr = A.transDateToString("yyyy-MM-dd",  max);
        System.out.println("最大日期： " + maxStr);
        
        cal.set(Calendar.DATE, mindate);
        Date min = cal.getTime();
        
        String minStr = A.transDateToString("yyyy-MM-dd", min);
        System.out.println("最小日期： " + minStr);
        
     
     }
     
     /**
      * 将data转为string
      *
      */
     public static String transDateToString(String format, Date date) {
      if (date == null)
       return " ";
      SimpleDateFormat sdf = new SimpleDateFormat(format);
      return sdf.