Java 集合 从HashMap中删除映射

在这个例子中，我们将看到如何使用键值对的键值从HashMap中删除特定的映射。我们将使用以下HashMap类方法来执行此操作：

public Value remove(Object key)：从此映射中移除指定键的映射（如果存在），并返回该特定键的元素值。

完整代码：

import java.util.HashMap;

public class RemoveMappingExample {

 public static void main(String[] args) {

    // Creating a HashMap of int keys and String values
    HashMap<Integer, String> hashmap = new HashMap<Integer, String>();

    // Adding Key and Value pairs to HashMap
    hashmap.put(11,"Value1");
    hashmap.put(22,"Value2");
    hashmap.put(33,"Value3");
    hashmap.put(44,"Value4");
    hashmap.put(55,"Value5");
    hashmap.put(66,"Value6");

    // Displaying HashMap Elements
    System.out.println("HashMap Elements: " + hashmap);

    // Removing Key-Value pairs for key 33
    Object removedElement1 = hashmap.remove(33);
    System.out.println("Element removed is: " +removedElement1);

    // Removing Key-Value pairs for key 55
    Object removedElement2 = hashmap.remove(55);
    System.out.println("Element removed is: " +removedElement2);

    // Displaying HashMap Elements after remove
    System.out.println("After Remove:");
    System.out.println("--------------");
    System.out.println("HashMap Elements: " + hashmap);
 }
}

输出：

HashMap Elements: {33=Value3, 55=Value5, 66=Value6, 22=Value2, 11=Value1, 44=Value4}
Element removed is: Value3
Element removed is: Value5
After Remove:
--------------
HashMap Elements: {66=Value6, 22=Value2, 11=Value1, 44=Value4}