黑色星期五

黑色星期五：每个月的13号恰逢星期五

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;

public class Demo {
	
	public static void main(String[] args) throws ParseException, IOException {
		String date;
		String newDate;
		System.out.println("请输入起始年份");
		BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
		int year = Integer.parseInt(reader.readLine());
		System.out.println("请输入未来几年的黑色星期五");
		int n = Integer.parseInt(reader.readLine());
		// 方式一：
		/*
		SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy MM dd E");
		for (int i = 0; i < n; i++) {
			for (int j = 1; j <= 12; j++) {
				newDate = year+i+" "+j+" "+13+" "+"星期一";
				date = dateFormat.format(dateFormat.parse(newDate));
				if(date.split(" ")[3].equals("星期五")){
					System.out.println(year+i+"年"+j+"月"+13+"日");
				}			
			}
		}	
		*/
		// 方式二：
		/*
		SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy MM dd E");
		for (int i = 1; i <= 12*n; i++) { // SimpleDateFormat中0月代表去年的12月
			newDate = year+" "+i+" "+13+" "+"星期一";
			date = dateFormat.format(dateFormat.parse(newDate));
			if(date.contains("星期五")){
				System.out.println(date);
			}
		}
		*/
		// 方式三：
		SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy MM dd E");
		Calendar calendar = Calendar.getInstance();
		for (int i = 0; i < n; i++) {
			for (int j = 0; j < 12; j++) { //Calendar中0月代表第一月
				calendar.set(year+i, j, 13);
				date = dateFormat.format(calendar.getTime());
				if(calendar.FRIDAY == calendar.get(Calendar.DAY_OF_WEEK)){
					System.out.println(date);
				}
			}
		}
	}

}