package com.ishang.test;

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

public class Test {
	/**
	  * 得到本周周一
	  *
	  * @return yyyy-MM-dd
	  */
	 public static String getMondayOfThisWeek() {
	  Calendar c = Calendar.getInstance();
	  int dayofweek = c.get(Calendar.DAY_OF_WEEK) - 1;
	  if (dayofweek == 0)
	   dayofweek = 7;
	  c.add(Calendar.DATE, -dayofweek + 1);
	  SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
	  System.out.println("本周第一天="+sdf.format(c.getTime()));
	  return sdf.format(c.getTime());
	 }

	/**
	  *得到本周周日 
	  * @return yyyy-MM-dd
	  */
	 public static String getSundayOfThisWeek() {
	  Calendar c = Calendar.getInstance();
	  int dayofweek = c.get(Calendar.DAY_OF_WEEK) - 1;
	  if (dayofweek == 0)
	   dayofweek = 7;
	  c.add(Calendar.DATE, -dayofweek + 7);
	  SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
	  System.out.println(sdf.format(c.getTime()));
	  return sdf.format(c.getTime());
	 }

	/**
	  * 得到本月最后一天
	  *
	  * @return
	  */
	 public static String getLastDateOfMonth()
	 {
	  SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd");
	  Date dt = new Date();
	  if (dt == null)
	   return null;
	  Calendar cal = Calendar.getInstance();
	  cal.setTime(dt);
	  int days = cal.getActualMaximum(Calendar.DAY_OF_MONTH);
	  cal.set(Calendar.DAY_OF_MONTH, days);
	  String result = format.format(cal.getTime());
	  System.out.println("一个月最后一天" + result);
	  return result;
	 }

	 /**
	  * 得到本月第一天
	  *
	  * @return
	  */
	 public static String getFristDateOfMonth()
	 {
	  SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd");
	  Date dt = new Date();
	  if (dt == null)
	   return null;
	  Calendar cal = Calendar.getInstance();
	  cal.setTime(dt);
	  int days = cal.getActualMinimum(Calendar.DAY_OF_MONTH);
	  cal.set(Calendar.DAY_OF_MONTH, days);
	  String result = format.format(cal.getTime());
	  System.out.println("一个月第一天" + result);
	  return result;
	 }
	 
	 public static void main(String[] args) {
		 getMondayOfThisWeek();
		 getSundayOfThisWeek();
		 getFristDateOfMonth();
		 getLastDateOfMonth();
	}
	}