如何检查日期是否在今天之后 java

Question

我正在尝试检查用户输入的日期是否晚于今天。这是我的代码：

SimpleDateFormat sdf = new SimpleDateFormat("yyyy/MM/dd");
Date enteredDate = sdf.parse(date);
Date currentDate = new Date();
if(enteredDate.after(currentDate)){

日期是一个变量，用户日期格式为“2016/04/26”。经过一些调试后，我发现 enteredDate 和 currentDate 为空。任何想法为什么会这样？谢谢

Answer 1

public class App {
    public static void main(String[] args) {
        String date = "2016/04/26";
        Date enteredDate = null;
        Date matcher = null;
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy/MM/dd");
        try {
            enteredDate = sdf.parse(date);
        } catch (Exception ex) {
            ex.printStackTrace();// enteredDate will be null if date="287686";
        }

        try {
            matcher = sdf.parse("2016/04/26");
        } catch (ParseException e) {
            // TODO Auto-generated catch block
            // e.printStackTrace();
        }

        if (enteredDate.compareTo(matcher) == 0) {
            System.out.println("enteredDate will be null");
        }

        Date currentDate = new Date();
        if (enteredDate.after(currentDate)) {
            System.out.println("after ");
        } else
            System.out.println("before");
    }
}

Answer 2

java 日期 class 有之前和之后的方法，你可以使用一个很好的例子是这个

`import java.text.SimpleDateFormat;
 import java.util.Date;
 import java.text.ParseException;
 public class App 
 {
     public static void main( String[] args ) 
     {
     try{

        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
        Date date1 = sdf.parse("2009-12-31");
        Date date2 = sdf.parse("2010-01-31");

        System.out.println(sdf.format(date1));
        System.out.println(sdf.format(date2));

        if(date1.compareTo(date2)>0){
            System.out.println("Date1 is after Date2");
        }else if(date1.compareTo(date2)<0){
            System.out.println("Date1 is before Date2");
        }else if(date1.compareTo(date2)==0){
            System.out.println("Date1 is equal to Date2");
        }else{
            System.out.println("How to get here?");
        }

    }catch(ParseException ex){
        ex.printStackTrace();
    }
}
}`

Answer 3

如评论中所述，日期对象不可能具有空引用。但是，如果 sdf.parse(date) 抛出一个被抑制的异常，则 enteredDate 可能为空。

 String date="2016/04/26";
    Date enteredDate=null;
    try
    {
    SimpleDateFormat sdf = new SimpleDateFormat("yyyy/MM/dd");
    enteredDate = sdf.parse(date);
    }catch (Exception ex)
    {
        // enteredDate will be null if date="287686";
    }
    Date currentDate = new Date();      
    if(enteredDate.after(currentDate)){
        System.out.println("after ");
    }else
        System.out.println("before");

如何检查日期是否在今天之后 java

How to check if a date is after today java

java

parsing

date

simpledateformat