Java 如何创建TreeMap

Java中的TreeMap与抽象类一起用于实现Map接口和NavigableMap。地图根据其键的自然排序或在地图创建时提供的比较器进行排序，这取决于使用哪个构造函数。

为了创建TreeMap，我们可以使用Map类或TreeMap类参考。

示例 1:

// Java program demonstrate how to create a TreeMap
  
import java.util.*;
  
class GFG {
  
    public static void main(String[] args)
    {
        // Declaring a treemap
        TreeMap<Integer, String> map;
  
        // Creating an empty TreeMap
        map = new TreeMap<Integer, String>();
  
        System.out.println("TreeMap successfully"
                           + " created");
    }
}

输出

TreeMap successfully created

示例 2:

// Java program demonstrate how to create and add elements
// to TreeMap
  
import java.util.*;
  
class GFG {
    public static void main(String[] args)
    {
        // Creating an empty TreeMap using Map interface
        Map<Integer, String> map = new TreeMap<>();
        
        System.out.println("TreeMap successfully"
                           + " created");
  
        // Adding elements
        map.put(1, "Geeks");
        map.put(2, "for");
        map.put(3, "Geeks");
  
        // Printing TreeMap
        System.out.println("TreeMap: " + map);
    }
}

输出

TreeMap successfully created
TreeMap: {1=Geeks, 2=for, 3=Geeks}