用Java编制一个日期计算程序

Question

1由用户输入一个月份，屏幕上输出这个月的月历，每星期一行，从星期日开始，到星期六结束。 2由用户输入一个日期，屏幕上回答是星期几。 3由用户输入两个日期，计算这两个日期之间相差多少天。

Answer 1

import java.util.Calendar; import java.util.Date; import java.util.Scanner; /** * */ /** * @author think * */ public class Test1 { /** * */ public Test1() { // TODO Auto-generated constructor stub } /** * function: * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub new Test1().print(); } /** * function: 打印函数 包含对当前输入的月历的打印 以及输入和输出的打印 */ public void print(){ //当月天数 //输入你的查询年月 如果直接输入月 默认是当前年 Scanner scanner = new Scanner(System.in); System.out.println("1.please input the month:"); int month = scanner.nextInt(); while(month <= 0 || month >12) { System.out.println("1.please input the month:"); month = scanner.nextInt(); } int days = days(month); String[] weeks = {"sun","mon","tue","wed","thr","Frd","sat"}; for (int i = 0; i < weeks.length; i++) { System.out.print(weeks[i]); for (int j = 0; j < 2; j++) { System.out.print(" "); } } System.out.println(); int weekOfday = getWeekOfday(month,1); //获得第一天的星期 for (int i = 0; i < (weekOfday - 1) * 5; i++) { System.out.print(" "); } for (int i = 1; i <= days; i++,weekOfday +=1) { if(weekOfday == 8) { weekOfday = 1; System.out.println(); System.out.print(i); } else { System.out.print(i); } for (int j = 0; j < 5 - (String.valueOf(i).length()); j++) { System.out.print(" "); } } System.out.println("\n"); System.out.println("2.please input the date(format is like:20030204):"); String date = scanner.next(); while(date.length() < 8) { System.out.println("2.please input the date(format is like:20030204):"); date = scanner.next(); } System.out.println("your input date weekday is:" + (getWeekDayStr(getWeekOfday(date)))); System.out.println("\n"); System.out.println("3.please input the compute date1(format is like:20030204):"); String date1 = scanner.next(); while(date.length() < 8) { System.out.println("3.please input the compute date1(format is like:20030204):"); date1 = scanner.next(); } System.out.println("3.please input the compute date2(format is like:20030204):"); String date2 = scanner.next(); while(date.length() < 8) { System.out.println("3.please input the compute date2(format is like:20030204):"); date2 = scanner.next(); } int xiangchadays = daysxiangcha(date1, date2); System.out.println("xiangcha days is:" + xiangchadays); } /** * function: 通过准确的年月日查询星期几的整数表示 * @param year * @param month * @param day * @return */ public int getWeekOfday(int year,int month, int day) { Calendar c = Calendar.getInstance(); c.set(Calendar.YEAR, year); c.set(Calendar.MONTH, month - 1); c.set(Calendar.DAY_OF_MONTH, day); return c.get(Calendar.DAY_OF_WEEK); } /** * function: 通过输入月日 查询星期几的整数表示 默认是当前年 * @param month * @param day * @return */ public int getWeekOfday(int month, int day) { Calendar c = Calendar.getInstance(); c.setTime(new Date()); int year = c.get(Calendar.YEAR); return getWeekOfday(year, month, day); } /** * function: 通过日期字符串获得星期几的整数表示 * @param dateStr * @return */ public int getWeekOfday(String dateStr) { int year =Integer.parseInt(dateStr.substring(0, 4)) ; int month =Integer.parseInt(dateStr.substring(4, 6)) ; int day =Integer.parseInt(dateStr.substring(6, 8)) ; return getWeekOfday(year, month, day); } /** * function: 返回星期几这样的表示 * @param weekday * @return */ public String getWeekDayStr(int weekday) { return weekDayStrs[weekday - Calendar.SUNDAY]; } String[] weekDayStrs = {"星期日","星期一","星期二","星期三","星期四","星期五","星期六"}; /** * function: 两个日期的相差天数 * @param dateStr1 20100205这样的格式 * @param dateStr2 20100205这样的格式 * @return */ public int daysxiangcha(String dateStr1,String dateStr2) { int year1 =Integer.parseInt(dateStr1.substring(0, 4)) ; int month1 =Integer.parseInt(dateStr1.substring(4, 6)) ; int day1 =Integer.parseInt(dateStr1.substring(6, 8)) ; int year2 =Integer.parseInt(dateStr2.substring(0, 4)) ; int month2 =Integer.parseInt(dateStr2.substring(4, 6)) ; int day2 =Integer.parseInt(dateStr2.substring(6, 8)) ; Calendar c1 = Calendar.getInstance(); c1.set(Calendar.YEAR, year1); c1.set(Calendar.MONTH, month1 -1); c1.set(Calendar.DAY_OF_MONTH, day1); Calendar c2 = Calendar.getInstance(); c2.set(Calendar.YEAR, year2); c2.set(Calendar.MONTH, month2 - 1); c2.set(Calendar.DAY_OF_MONTH, day2); long mills = c1.getTimeInMillis() > c2.getTimeInMillis()? c1.getTimeInMillis() - c2.getTimeInMillis(): c2.getTimeInMillis() - c1.getTimeInMillis(); return (int)(mills/1000/3600/24); } /** * @param year * @param month * @return 某年某月的天数 */ public static int days(int year,int month) { int days = 0; if(month!=2) { switch(month) { case 1: case 3: case 5: case 7: case 8: case 10: case 12:days = 31 ;break; case 4: case 6: case 9: case 11:days = 30; } } else { if(year%4==0 && year%100!=0 || year%400==0) days = 29; else days = 28; } return days; } /** * function: 查询某月的天数 默认是当前年份 * @param month * @return */ public static int days(int month) { Calendar c = Calendar.getInstance(); c.setTime(new Date()); int year = c.get(Calendar.YEAR); return days(year, month); } }