Java DateFormat equals()方法及实例

DateFormat 类的 equals() 方法是用来比较两个DateFormat对象。如果这个DateFormat等于所传递的对象，该方法返回True，否则返回False。

语法

public boolean equals(Object obj)

参数： 该方法需要一个对象类型的参数obj，指的是要与这个DateFormat对象进行比较的对象。

返回值： 如果两个对象都相等，该方法将返回布尔值True，否则该方法将返回False。

下面的程序说明了DateFormat的equals()方法的工作原理：

示例1 :

// Java code to illustrate equals() method  import java.text.*;import java.util.*;  public class DateFormat_Demo {    public static void main(String[] args)    {        // Initializing the first formatter        DateFormat DFormat1            = DateFormat.getDateInstance();          // Initializing the second formatter        DateFormat DFormat2            = DateFormat.getDateInstance();          // Displaying both the Formats        Date date = new Date();        String str_Date1            = DFormat1.format(date);        System.out.println("First: "                           + (str_Date1));          String str_Date2            = DFormat2.format(date);        System.out.println("Second: "                           + (str_Date2));          // Comparing both the objects        System.out.println("Equality: "                           + DFormat1.equals(DFormat2));    }}

输出:

First: Mar 27, 2019Second: Mar 27, 2019Equality: true

例2 :

// Java code to illustrate equals() method  import java.text.*;import java.util.*;  public class DateFormat_Demo {    public static void main(String[] args)    {        // Initializing the first formatter        DateFormat DFormat1            = DateFormat.getDateInstance();          // Initializing the second formatter        DateFormat DFormat2            = DateFormat.getTimeInstance();          // Displaying both the Formats        Date date = new Date();        String str_Date1            = DFormat1.format(date);        System.out.println("First: "                           + (str_Date1));          String str_Date2            = DFormat2.format(date);        System.out.println("Second: "                           + (str_Date2));          // Comparing both the objects        System.out.println("Equality: "                           + DFormat1.equals(DFormat2));    }}

输出:

First: Mar 27, 2019Second: 11:04:25 AMEquality: false

参考资料: https://docs.oracle.com/javase/7/docs/api/java/text/DateFormat.html#equals(java.lang.Object)