我已经实现了以下代码来计算剩余的剩余天数。我使用SimpleDateFormat将字符串转换为日期。如果我输入10/02/1993(今天' s日期)作为日期,则输出显示0天。但如果我选择11/02/1993,它会显示与剩余0天相同的输出。但是,如果我改变月份,即22/07/1993,则显示剩余160天而不是162天,这是原始结果。我在这做错了什么?任何帮助是极大的赞赏。
private static void calculateNextBirthday() {
Scanner in = new Scanner(System.in);
System.out.println("Enter your birthday(dd/MM/yyyy)");
user_input = in.nextLine();
SimpleDateFormat formatter = new SimpleDateFormat("dd/MM/yyyy");
Calendar user_selected_day = new GregorianCalendar();
Calendar today = new GregorianCalendar();
Date selected_date = null;
try {
selected_date = formatter.parse(user_input);
} catch (ParseException e) {
e.printStackTrace();
}
user_selected_day.setTime(selected_date);
int user_selected_month = user_selected_day.get(Calendar.MONTH);
int CMonth = today.get(Calendar.MONTH);
int user_selected_date = user_selected_day.get(Calendar.DAY_OF_MONTH);
int CDate = today.get(Calendar.DAY_OF_MONTH);
user_selected_day.set(Calendar.YEAR, today.get(Calendar.YEAR));
user_selected_day.set(Calendar.DAY_OF_WEEK,today.get(Calendar.DAY_OF_WEEK));
if (user_selected_month < CMonth) {
user_selected_day.set(Calendar.YEAR,today.get(Calendar.YEAR) + 1);
}
else if (user_selected_month == CMonth){
if(user_selected_date < CDate){
user_selected_day.set(Calendar.YEAR,today.get(Calendar.YEAR) + 1);
}
}
long millis = user_selected_day.getTimeInMillis() - today.getTimeInMillis();
long days;
days = (millis / (24 * 60 * 60 * 1000));
System.out.println(String.valueOf(days) + " days left!!");
}
更新:我已更新下面的代码,它运行正常。希望它能帮助将来的某个人。
` SimpleDateFormat formatter = new SimpleDateFormat("dd/MM/yyyy");
Calendar user_selected_day = new GregorianCalendar();
Calendar today = new GregorianCalendar();
Date selected_date = null;
try {
selected_date = formatter.parse(plainDate);
} catch (ParseException e) {
e.printStackTrace();
}
user_selected_day.setTime(selected_date);
int user_selected_month = user_selected_day.get(Calendar.MONTH);
int CMonth = today.get(Calendar.MONTH);
int user_selected_date = user_selected_day.get(Calendar.DAY_OF_MONTH);
int CDate = today.get(Calendar.DAY_OF_MONTH);
user_selected_day.set(Calendar.YEAR, today.get(Calendar.YEAR));
user_selected_day.set(Calendar.HOUR_OF_DAY,today.get(Calendar.HOUR_OF_DAY));
user_selected_day.set(Calendar.MINUTE,today.get(Calendar.MINUTE));
user_selected_day.set(Calendar.SECOND,today.get(Calendar.SECOND));
user_selected_day.set(Calendar.MILLISECOND,today.get(Calendar.MILLISECOND));
if (user_selected_month < CMonth) {
user_selected_day.set(Calendar.YEAR,today.get(Calendar.YEAR) + 1);
}
else if (user_selected_month == CMonth){
if(user_selected_date < CDate){
user_selected_day.set(Calendar.YEAR,today.get(Calendar.YEAR) + 1);
}
}
long millis = user_selected_day.getTimeInMillis() - today.getTimeInMillis();
long days;
if(user_selected_day.getTime()==today.getTime()){
days = 0;
}
else{
days = (millis / (24 * 60 * 60 * 1000));
}`
答案 0 :(得分:1)
问题出在
行user_selected_day.set(Calendar.YEAR, today.get(Calendar.YEAR));
这会将今天的年份设置为user_selected
天,并且当月份相等时,它将进入 elseif 并且不进行任何更改。
同时检查你提到的if else条件。
答案 1 :(得分:1)
您还可以在Java 8中使用LocalDate
类来随时添加/减去日期。
java.time
提供Period
类来表示一段时间,例如 几天,或几小时和几分钟。LocalDate
和朋友们提供 添加或减去句号或其他内容的plus()
和minus()
方法 时间相关的对象。 Period提供工厂方法,例如ofDays()
。
阅读此示例以供参考。它计算从现在开始的700
天的日期:
/**
* DateAdd -- compute the difference between two dates (e.g., today and 700 days
* from now).
*/
public class Main {
public static void main(String[] av) {
/** Today's date */
LocalDate now = LocalDate.now();
Period p = Period.ofDays(700);
LocalDate then = now.plus(p);
System.out.printf("Seven hundred days from %s is %s%n", now, then);
}
}
运行此程序会报告当前日期和时间,以及从现在起七百天后的日期和时间。例如:
Seven hundred days from 2013-11-09 is 2015-10-10
答案 2 :(得分:0)
不要自己进行计算。获得Calendar对象后,使用&#34; add&#34;增加所需值的方法。