Java SortedMap equals()方法及示例

SortedMap Java中的 equals() 方法用于检查两个SortedMap实例之间是否相等。它验证作为参数传递的一个SortedMap的元素是否与这个SortedMap的元素相等。

语法

boolean equals(object obj)

参数： 该方法接受一个该地图类型的参数obj，并指的是要与该地图进行平等检查的地图。

返回值： 如果obj和地图的平等性都成立，该方法返回 true ，否则返回 false

注意 ：SortedMap中的equals()方法是继承自Java中的Map接口。

下面的程序说明了equals()方法。

程序1 :

// Java code to illustrate// the equals() method  import java.util.*;  public class Map_Demo {    public static void main(String[] args)    {          // Creating an empty SortedMap        SortedMap<Integer, String> map1            = new TreeMap<Integer, String>();        SortedMap<Integer, String> map2            = new TreeMap<Integer, String>();          // Mapping string values to int keys        map1.put(10, "Geeks");        map1.put(15, "4");        map1.put(20, "Geeks");        map1.put(25, "Welcomes");        map1.put(30, "You");          // Mapping string values to int keys        map2.put(10, "Geeks");        map2.put(15, "4");        map2.put(20, "Geeks");        map2.put(25, "Welcomes");        map2.put(30, "You");          // Displaying the Map1        System.out.println("First Map: "                           + map1);          // Displaying the Map2        System.out.println("Second Map: "                           + map2);          // Checking the equality        System.out.println(            "Equality: "            + map1.equals(map2));    }}

输出:

First Map: {10=Geeks, 15=4, 20=Geeks, 25=Welcomes, 30=You}Second Map: {10=Geeks, 15=4, 20=Geeks, 25=Welcomes, 30=You}Equality: true

程序2

// Java code to illustrate// the equals() method  import java.util.*;  public class Map_Demo {    public static void main(String[] args)    {          // Creating an empty SortedMap        SortedMap<Integer, String> map1            = new TreeMap<Integer, String>();        SortedMap<Integer, String> map2            = new TreeMap<Integer, String>();          // Mapping string values        // to int keys for map1        map1.put(10, "Geeks");        map1.put(15, "4");        map1.put(20, "Geeks");        map1.put(25, "Welcomes");        map1.put(30, "You");          // Mapping string values        // to int keys for map2        map2.put(10, "Geeks");        map2.put(15, "4");        map2.put(20, "Geek");        map2.put(25, "Welcomes");        map2.put(30, "You");          // Displaying the map 1        System.out.println("First Map: "                           + map1);          // Displaying the map 2        System.out.println("Second Map: "                           + map2);          // Displaying the equality        System.out.println("Equality: "                           + map1.equals(map2));    }}

输出:

First Map: {10=Geeks, 15=4, 20=Geeks, 25=Welcomes, 30=You}Second Map: {10=Geeks, 15=4, 20=Geek, 25=Welcomes, 30=You}Equality: false

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