Java 中的 Collections checkedSortedMap()方法，带示例

原文:https://www . geesforgeks . org/collections-checked sortedmap-method-in-Java-with-examples/

java.util.Collections 类的 checkedSortedMap() 方法用于返回指定排序地图的动态类型安全视图。 如果指定的映射是可序列化的，则返回的映射将是可序列化的。 因为 null 被认为是任何引用类型的值，所以返回的映射允许在后备映射插入 null 键或值时插入。 语法:

public static  SortedMap
 checkedSortedMap(SortedMap m, Class keyType, Class valueType)

参数:该方法将以下参数作为参数

  • m–为其返回动态类型安全视图的地图
  • 钥匙类型–允许 m 持有的钥匙类型
  • 值类型–允许 m 持有的值类型

返回值:该方法动态返回指定地图的类型安全视图。 以下举例说明 checkedSortedMap() 方法 例 1:

Java 语言(一种计算机语言，尤用于创建网站)

// Java program to demonstrate
// checkedSortedMap() method
// for <String, String> type

import java.util.*;

public class GFG1 {
    public static void main(String[] argv)
        throws Exception
    {
        try {

            // creating object of SortedMap<String, String>
            SortedMap<String, String>
                smap = new TreeMap<String, String>();

            // Adding element to smap
            smap.put("Ram", "Gopal");
            smap.put("Karan", "Arjun");
            smap.put("Karn", "Veer");

            // printing the sorted map
            System.out.println("Sorted map:\n"
                               + smap);

            // create typesafe view of the specified map
            SortedMap<String, String>
                tsmap = Collections
                            .checkedSortedMap(smap,

<strong>Output:</strong>
<pre>{Karan=39, Karn=40, Ram=20}</pre>
                                              String.class,
                                              String.class);

            // printing the typesafe view of specified sorted map
            System.out.println("Typesafe view of sorted map:\n"
                               + tsmap);
        }

        catch (IllegalArgumentException e) {
            System.out.println("Exception thrown : " + e);
        }
    }
}

Output: 

Sorted map:
{Karan=Arjun, Karn=Veer, Ram=Gopal}
Typesafe view of sorted map:
{Karan=Arjun, Karn=Veer, Ram=Gopal}

例 2:

Java 语言(一种计算机语言，尤用于创建网站)

// Java program to demonstrate
// checkedSortedMap() method
// for <String, Integer> type

import java.util.*;

public class GFG1 {
    public static void main(String[] argv) throws Exception
    {
        try {

            // creating object of SortedMap<String, Integer>
            SortedMap<String, Integer> smap = new TreeMap<String, Integer>();

            // Adding element to smap
            smap.put("Ram", 20);
            smap.put("Karan", 39);
            smap.put("Karn", 40);
            // printing the sorted map
            System.out.println("Sorted map:\n"
                               + smap);

            // create typesafe view of the specified map
            SortedMap<String, Integer>
                tsmap = Collections
                            .checkedSortedMap(smap,
                                              String.class,
                                              Integer.class);

            // printing the typesafe view of specified sorted map
            System.out.println("Typesafe view of sorted map:\n"
                               + tsmap);
        }
        catch (IllegalArgumentException e) {

            System.out.println("Exception thrown : " + e);
        }
    }
}

Output: 

Sorted map:
{Karan=39, Karn=40, Ram=20}
Typesafe view of sorted map:
{Karan=39, Karn=40, Ram=20}

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