我完全迷失在这个问题上。我们要创建一个程序，允许用户输入日期（月，日，年），程序应打印出该日期，并在每天后增加1。如果日期输入在该月的最后一天下降。月份需要加1，第二天应该重新开始1.如果是12月31日，则输入xxx1。那么月，日和年应该改为1月1日，xxx2。此外，如果日期是闰年。比如说输入是2009年2月15日。如果不是2月28日打印出来的闰年，日期应该增加到2月29日。
我完全不知道如何解决这个问题。如果有人能指出我正确的方向，我将非常感激。
我在这里：
package date;
public class Date
{
private static final int February = 2;
private static final int December = 12;
private int month;
private int day;
private int year;
public Date()
{
month = 1;
day = 1;
year = 2000;
}
public Date(int month, int day, int year)
{
this.month = month;
this.day = day;
this.year = year;
}
public void setMonth(int month)
{
this.month = month;
}
public void setDay(int day)
{
this.day = day;
}
public void setYear(int year)
{
this.year = year;
}
public int getMonth(int month)
{
return month;
}
public int getDay(int day)
{
return day;
}
public static int getYear(int year)
{
return year;
}
public boolean nextDay()
{
boolean leapYear = false;
int currentMonthMaxDays;
int [] daysInMonths = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
currentMonthMaxDays = daysInMonths[month];
if(day < currentMonthMaxDays)
{
day = day + 1;
day++;
}
else if(month == February && leapYear && day == 28)
{
day = 29;
day++;
}
else day = 1;
if(month != December)
month +=1;
else
year+=1;
month = 1;
while(!leapYear)
{
if(year % 400 ==0)
leapYear = true;
else if(year % 4 == 0 && year % 100 != 0)
leapYear = true;
}
return leapYear;
}
}
我认为我正确地完成了Date.java类，我的问题在于主类。我们必须创建一个数组，将日期增加1.我试图每月查看30-31天。
这是DateTest主页：
package date;
import java.text.SimpleDateFormat;
import java.util.Date;
import javax.swing.JOptionPane;
public class DateTest {
public static void main(String[] args)
{
Date [] date = new Date[2];
for(int i = 1; i < date.length; i++)
{
JOptionPane.showInputDialog("Enter Date (e.g. 19991231): ");
date[i] = new Date();
i++;
}
new SimpleDateFormat("EEEE, MMMM d, yyyy");
JOptionPane.showMessageDialog(null, "Date: " + date, "Results", JOptionPane.PLAIN_MESSAGE);
}
}
我确信我的主要是非常高兴。而且我真的迷失在任务上。
答案 0 :(得分：0)
我评论说，将日期内部存储为基准日期之后的天数将更容易编码。
这是Date类的一个版本，它在内部将日期存储为基准日期之后的天数：
package com.ggl.testing;
import java.security.InvalidParameterException;
public class Date {
private static final boolean DEBUG = false;
private static final int BASE_MONTH = 1;
private static final int BASE_YEAR = 1700;
private int days;
public Date(int month, int day, int year) {
setDate(month, day, year);
}
public void setDate(int month, int day, int year) {
if ((month >= 1) && (month <= 12)) {
} else {
String s = "Month not between 1 and 12";
throw new InvalidParameterException(s);
}
if (year >= BASE_YEAR) {
int temp = calculateMonthDays(month, year);
if ((day >= 1) && (day <= temp)) {
} else {
String s = "Day not between 1 and " + temp;
throw new InvalidParameterException(s);
}
int days = calculateYearDays(year);
if (DEBUG) {
System.out.println(days);
System.out.println(temp);
}
days += temp;
this.days = days + day;
if (DEBUG) {
System.out.println(day);
System.out.println(this.days);
}
} else {
String s = "Year before " + BASE_YEAR;
throw new InvalidParameterException(s);
}
}
public int[] getDate() {
int days = this.days;
if (DEBUG) System.out.println(days);
int year = BASE_YEAR;
int decrement = daysInYear(year);
while (days > decrement) {
days -= decrement;
decrement = daysInYear(++year);
}
if (DEBUG) System.out.println(days);
int month = BASE_MONTH;
decrement = daysInMonth(month, year);
while (days > decrement) {
days -= decrement;
decrement = daysInMonth(++month, year);
}
if (DEBUG) System.out.println(days);
int day = days;
int[] result = new int[3];
result[0] = month;
result[1] = day;
result[2] = year;
return result;
}
public String getFormattedDate() {
String[] months = {"Jan", "Feb", "Mar", "Apr", "May", "Jun",
"Jul", "Aug", "Sep", "Oct", "Nov", "Dec"};
int[] fields = getDate();
return String.format("%s %d, %d", months[fields[0] - 1],
fields[1], fields[2]);
}
public void addDays(int increment) {
this.days += increment;
}
private int calculateMonthDays(int month, int year) {
int days = 0;
for (int i = BASE_MONTH; i < month; i++) {
days += daysInMonth(i, year);
}
return days;
}
private int calculateYearDays(int year) {
int days = 0;
for (int i = BASE_YEAR; i < year; i++) {
days += daysInYear(i);
}
return days;
}
private int daysInMonth(int month, int year) {
int[] days = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
if (month == 2) {
if (daysInYear(year) > 365) {
return days[month - 1] + 1;
}
}
return days[month - 1];
}
private int daysInYear(int year) {
int days = 365;
if ((year % 4) == 0) {
if ((year % 100) == 0) {
if ((year % 400) == 0) {
days++;
}
} else {
days++;
}
}
return days;
}
public static void main(String[] args) {
Date date = new Date(6, 12, 2014);
displayResult(date, 10);
date = new Date(6, 12, 2014);
displayResult(date, 20);
date = new Date(12, 15, 2014);
displayResult(date, 20);
date = new Date(12, 15, 1955);
displayResult(date, 30);
date = new Date(12, 15, 1955);
displayResult(date, -30);
date = new Date(12, 15, 1955);
displayResult(date, 16);
date = new Date(12, 15, 1955);
displayResult(date, 17);
date = new Date(12, 15, 1955);
displayResult(date, 80);
date = new Date(12, 15, 1956);
displayResult(date, 80);
date = new Date(3, 5, 1957);
displayResult(date, -80);
date = new Date(3, 5, 1956);
displayResult(date, -80);
}
private static void displayResult(Date date, int increment) {
String sign = "";
int display = 0;
if (increment > 0) {
sign = " + ";
display = increment;
} else {
sign = " - ";
display = -increment;
}
System.out.print(date.getFormattedDate() + sign +
display + " days -> ");
date.addDays(increment);
System.out.println(date.getFormattedDate());
}
}
以下是一些测试结果。
Jun 12, 2014 + 10 days -> Jun 22, 2014
Jun 12, 2014 + 20 days -> Jul 2, 2014
Dec 15, 2014 + 20 days -> Jan 4, 2015
Dec 15, 1955 + 30 days -> Jan 14, 1956
Dec 15, 1955 - 30 days -> Nov 15, 1955
Dec 15, 1955 + 16 days -> Dec 31, 1955
Dec 15, 1955 + 17 days -> Jan 1, 1956
Dec 15, 1955 + 80 days -> Mar 4, 1956
Dec 15, 1956 + 80 days -> Mar 5, 1957
Mar 5, 1957 - 80 days -> Dec 15, 1956
Mar 5, 1956 - 80 days -> Dec 16, 1955
使用相同的私有方法将日期转换为整数，并将整数转换为日期有助于一些。 DEBUG显示帮助我解决了其他错误。