标签：
问题：① 完善set()方法，保证获得正确的日期值(合法性)；
② 将tomorrow()和yestoday()方法合并为以下daysAfter()方法，并增加一些方法：
public int getWeek() //返回当前日期对应的星期几，范围为0～6
public String toWeekString() //返回当前日期对应星期几的中文字符串
public boolean before(MyDate d) //判断是否在指定日期之前
public int daysBetween(MyDate d) //返回当前日期与日期d之间相距的天数
public boolean equals(Object obj) //比较两个对象是否相等
import java.util.Calendar;
import java.util.Scanner;
public class MyDate2 {
int year,month,day;
boolean isCorrect=true;
private static int thisYear;
static {
thisYear=Calendar.getInstance().get(Calendar.YEAR); //获得当前日期对象中的年份值
}
public MyDate2(int year, int month, int day) {
this.set(year, month, day);
}
public MyDate2() {
this(1970,1,1); //调用本类已声明的其他构造方法
}
public MyDate2(MyDate2 d) {
this.set(d);
}
public void set(int y, int m, int d) {
if(y<1){
System.out.println("Input Year Is Error !!!");
this.isCorrect=false;
return ;
}if(m<1||m>12){
System.out.println("Input Month Is Error !!!");
this.isCorrect=false;
return ;
}
if(day<=0 || day>daysOfMonth() ){
System.out.println("Input Day Is Error !!!");
this.isCorrect=false;
return ;
}
this.year = y;
this.month = m;
this.day = d ;
}
public void set(MyDate2 d) {
set(d.year, d.month, d.day); //调用同名成员方法，不能使用this()
}
public String toString(){
return this.year+"年"+this.month+"月"+this.day+"日";
}
public static int getThisYear(){
return thisYear; //访问静态成员变量
}
public static boolean isLeapYear(int year) {
return year%400==0 || year%100!=0 && year%4==0;
}
public boolean isLeapYear() {
return isLeapYear(this.year); //调用静态方法
}
public boolean equals(MyDate2 d) { //this指代调用本
方法的当前对象
return this==d || d!=null && this.year==d.year && this.month==d.month && this.day==d.day;
}
public boolean equals(Object obj) {
if (this==obj) //this指代调用当前方法的对象
return true;
if (obj instanceof MyDate2) {
MyDate2 d = (MyDate2)obj; //类型强制转换
return this.year==d.year && this.month==d.month && this.day==d.day;
}
return false;
}
public static int daysOfMonth(int year, int month) {
switch (month) //计算每月的天数
{
case 1: case 3: case 5: case 7: case 8: case 10: case 12: return 31;
case 4: case 6: case 9: case 11: return 30;
case 2: return isLeapYear(year)?29:28;
default: return 0;
}
}
public int daysOfMonth() {
return daysOfMonth(this.year, this.month);
}
public void tomorrow() {
this.day++; //通过this改变当前对象的值，没有返回值
if (day>this.daysOfMonth()){
day=1;
month++;
if (month>12)
{
month=1;
year++;
}
}
}
public MyDate2 yestoday() {
MyDate2 yes=new MyDate2(this); //执行拷贝构造方法，创建新实例，没有改变当前对象
this
yes.day--;
if (yes.day==0) {
yes.month--;
if (yes.month==0){
yes.month=12;
yes.year--;
}
yes.day = daysOfMonth(yes.year, yes.month);
}
return yes; //返回对象引用
}
public MyDate2 dayAfter(int n) {
MyDate2 yes=new MyDate2(this); //执行拷贝构造方法，创建新实例，没有改变当前对象
this
yes.day+=n;
if (yes.day==0) {
yes.month--;
if (yes.month==0){
yes.month=12;
yes.year--;
}
yes.day = daysOfMonth(yes.year, yes.month);
//System.out.println("**"+yes.year+" "+yes.month+" "+yes.day);
return yes;
}
if (yes.day>this.daysOfMonth()){
yes.day=1;
yes.month++;
if (yes.month>12)
{
yes.month=1;
yes.year++;
}
}
return yes; //返回对象引用
}
public int getSumDays(MyDate2 d){
int sum=0;
for(int i=1;i<d.year;i++){
sum+=d.isLeapYear(i) ? 366 : 365;
}
for(int i=1;i<d.month;i++){
sum+=d.daysOfMonth(d.year,i);
}
sum+=d.day;
return sum;
}
public int getWeek(){
long sum=0;
int week;
for(int i=1;i<this.year;i++){
sum+=this.isLeapYear(i) ? 366 : 365;
}
for(int i=1;i<this.month;i++){
sum+=this.daysOfMonth(this.year,i);
}
sum+=this.day;
week=(int)sum%7;
return week;
}
public String toWeekString(){
switch (getWeek()){
case 0 : return "Sunday" ;
case 1 : return "Monday" ;
case 2 : return "Tuesay" ;
case 3 : return "Wednesday" ;
case 4 : return "Thursday" ;
case 5 : return "Friday" ;
default : return "Saturday" ;
}
}
public boolean before(MyDate2 d){
if(this.year<d.year){
return true;
}else if(this.year==d.year){
if(this.month<d.month){
return true;
}else if(this.month==d.month){
if(this.day<d.day){
return true;
}else{
return false;
}
}else{
return false;
}
}else{
return false;
}
}
public int daysBetween(MyDate2 d){
int a=getSumDays(d);
int b=getSumDays(this);
return Math.abs(a-b);
}
}
class MyDate_ex
{
public static void main(String args[])
{
Scanner sc=new Scanner(System.in);
System.out.println("Please input date : ");
while(sc.hasNext()){
MyDate2 d= new MyDate2(sc.nextInt(),sc.nextInt(),sc.nextInt());
if(d.isCorrect){
System.out.println("If you want to konw yestoday date,please input -1 ");
System.out.println("or tomorrow date,please input 1");
System.out.println(d.dayAfter(sc.nextInt()));
System.out.println("Week : "+d.getWeek()+" "+d.toWeekString());
System.out.println("Input a cmparative date : ");
MyDate2 r=new MyDate2(sc.nextInt(),sc.nextInt(),sc.nextInt());
System.out.println(d.before(r));
System.out.println("Date_d between Date_r have "+d.daysBetween(r)+" days");
}
System.out.println();
System.out.println("Please input date : ");
}
}
}
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原文地址：http://blog.csdn.net/u011479875/article/details/45438691
