package com.dada.test;


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

/**
 * @author li_yueling
 * @version 1.0 2011-03-25
 *
 */
public class DateUtil {
	/**
	 * 預設日期格式
	 */
	public static String DEFAULT_FORMAT = "yyyy-MM-dd";

	/**
	 * 測試主方法
	 * @param args
	 */
	public static void main(String[] args) {
		for(int i = 1951;i < 1960;i++){
			System.out.println(formatDate(getYearFirst(i)));
			System.out.println(formatDate(getYearLast(i)));
		}
		
		System.out.println(formatDate(getCurrYearFirst()));
		System.out.println(formatDate(getCurrYearLast()));

	}
	
	/**
	 * 格式化日期
	 * @param date 日期物件
	 * @return String 日期字串
	 */
	public static String formatDate(Date date){
		SimpleDateFormat f = new SimpleDateFormat(DEFAULT_FORMAT);
		String sDate = f.format(date);
		return sDate;
	}
	
	/**
	 * 獲取當年的第一天
	 * @param year
	 * @return
	 */
	public static Date getCurrYearFirst(){
		Calendar currCal=Calendar.getInstance();  
		int currentYear = currCal.get(Calendar.YEAR);
		return getYearFirst(currentYear);
	}
	
	/**
	 * 獲取當年的最後一天
	 * @param year
	 * @return
	 */
	public static Date getCurrYearLast(){
		Calendar currCal=Calendar.getInstance();  
		int currentYear = currCal.get(Calendar.YEAR);
		return getYearLast(currentYear);
	}
	
	/**
	 * 獲取某年第一天日期
	 * @param year 年份
	 * @return Date
	 */
	public static Date getYearFirst(int year){
		Calendar calendar = Calendar.getInstance();
		calendar.clear();
		calendar.set(Calendar.YEAR, year);
		Date currYearFirst = calendar.getTime();
		return currYearFirst;
	}
	
	/**
	 * 獲取某年最後一天日期
	 * @param year 年份
	 * @return Date
	 */
	public static Date getYearLast(int year){
		Calendar calendar = Calendar.getInstance();
		calendar.clear();
		calendar.set(Calendar.YEAR, year);
		calendar.roll(Calendar.DAY_OF_YEAR, -1);
		Date currYearLast = calendar.getTime();
		
		return currYearLast;
	}

}