求个时间算法。

bx_521 2013-08-28 04:28:48

需求：求近一年的每周的周一，周日的日期格式为yyyy-MM-dd.

1：近一年为系统当前日期一直到去年的当前日期：例如，当前日期为2013-08-28，则需要从2012-08-28所在周的周一开始算起，一直到2013-08-28所在周，其中需要每周的周一和周日日期。

2：求某年每个月的第一天和最后一天（共12个月）。

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bx_521 2013-08-29

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引用 3 楼 preferme 的回复:

啥也不说，直接上代码。

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


public class Test_11 {

	private static final SimpleDateFormat SDF = new SimpleDateFormat("yyyy-MM-dd");
	
	/**
	 * 测试用例
	 */
	public static void main(String[] args) {
		List<String> days1 = findDays_1(new Date());
		for(String day : days1){
			System.out.println(day);
		}
		System.out.println("-------- 我是分割线 -----------");
		List<String> days2 = findDays_2(2013);
		for(String day : days2){
			System.out.println(day);
		}
	}

	public static List<String> findDays_1(Date day){
		ArrayList<String> days = new ArrayList<String>();
		Calendar cal = Calendar.getInstance();
		cal.setTime(day);
		cal.set(Calendar.DAY_OF_WEEK, Calendar.MONDAY);
		cal.add(Calendar.DAY_OF_MONTH, 1);
		Date end = cal.getTime();
		cal.setTime(day);
		cal.add(Calendar.YEAR, -1);
		Date cur = null;
		do{
			cal.set(Calendar.DAY_OF_WEEK, Calendar.MONDAY);
//			Date monday = cal.getTime();
			days.add(SDF.format(cal.getTime()));
			cal.add(Calendar.DAY_OF_MONTH, 6);
			cur = cal.getTime();
			days.add(SDF.format(cur));
		}while(cur.before(end));
		return days;
	}
	
	public static List<String> findDays_2(int year){
		ArrayList<String> days = new ArrayList<String>();
		Calendar cal = Calendar.getInstance();
		cal.set(Calendar.YEAR, year);
		cal.set(Calendar.MONTH, 0);
		cal.set(Calendar.DAY_OF_MONTH, 1);
		for(int i=0;i<12;i++){
			days.add(SDF.format(cal.getTime()));
			cal.add(Calendar.MONTH, 1);
			cal.add(Calendar.DAY_OF_MONTH, -1);
			days.add(SDF.format(cal.getTime()));
			cal.add(Calendar.DAY_OF_MONTH, 1);
		}
		return days;
	}
	
}

谢谢很受益

冰思雨 2013-08-28

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啥也不说，直接上代码。

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


public class Test_11 {

	private static final SimpleDateFormat SDF = new SimpleDateFormat("yyyy-MM-dd");
	
	/**
	 * 测试用例
	 */
	public static void main(String[] args) {
		List<String> days1 = findDays_1(new Date());
		for(String day : days1){
			System.out.println(day);
		}
		System.out.println("-------- 我是分割线 -----------");
		List<String> days2 = findDays_2(2013);
		for(String day : days2){
			System.out.println(day);
		}
	}

	public static List<String> findDays_1(Date day){
		ArrayList<String> days = new ArrayList<String>();
		Calendar cal = Calendar.getInstance();
		cal.setTime(day);
		cal.set(Calendar.DAY_OF_WEEK, Calendar.MONDAY);
		cal.add(Calendar.DAY_OF_MONTH, 1);
		Date end = cal.getTime();
		cal.setTime(day);
		cal.add(Calendar.YEAR, -1);
		Date cur = null;
		do{
			cal.set(Calendar.DAY_OF_WEEK, Calendar.MONDAY);
//			Date monday = cal.getTime();
			days.add(SDF.format(cal.getTime()));
			cal.add(Calendar.DAY_OF_MONTH, 6);
			cur = cal.getTime();
			days.add(SDF.format(cur));
		}while(cur.before(end));
		return days;
	}
	
	public static List<String> findDays_2(int year){
		ArrayList<String> days = new ArrayList<String>();
		Calendar cal = Calendar.getInstance();
		cal.set(Calendar.YEAR, year);
		cal.set(Calendar.MONTH, 0);
		cal.set(Calendar.DAY_OF_MONTH, 1);
		for(int i=0;i<12;i++){
			days.add(SDF.format(cal.getTime()));
			cal.add(Calendar.MONTH, 1);
			cal.add(Calendar.DAY_OF_MONTH, -1);
			days.add(SDF.format(cal.getTime()));
			cal.add(Calendar.DAY_OF_MONTH, 1);
		}
		return days;
	}
	
}

lcf 2013-08-28