treeset比较器

TreeSet类的compare()方法 (TreeSet Class comparator() method)

• comparator() method is available in java.util package.

  比较器()方法在java.util包中可用。

• comparator() method is used to get the Comparator object based on customizing order the elements in this TreeSet.

  比较器()方法用于基于自定义此TreeSet中元素的顺序来获取Comparator对象。

• comparator() method is a non-static method, it is accessible with the class object only and if we try to access the method with the class name then we will get an error.

  比较器()方法是一种非静态方法，只能通过类对象访问，如果尝试使用类名称访问该方法，则会收到错误消息。

• comparator() method does not throw an exception at the time of returning the Comparator object.

  返回Comparator对象时，compareor ()方法不会引发异常。

Syntax:

句法：

    public Comparator comparator();

Parameter(s):

参数：

• It does not accept any parameter.

  它不接受任何参数。

Return value:

返回值：

The return type of the method is Comparator, it gets Comparator based on defining the order of elements in this TreeSet otherwise it returns null when this TreeSet follows defalult ordering its elements.

方法的返回类型为Comparator ，它基于定义此TreeSet中元素的顺序来获取Comparator，否则，当此TreeSet遵循默认元素顺序时，它返回null。

Example:

例：

// Java program to demonstrate the example
// of Comparator comparator() method of TreeSet
import java.util.*;
public class ComparatorOfTreeSet {public static void main(String[] args) {// Instantiates a TreeSet object
TreeSet < String > tree_set = new TreeSet < String > ();
// By using add() method is to add
// the given object of this TreeSet
tree_set.add("C");
tree_set.add("C++");
tree_set.add("JAVA");
tree_set.add("PHP");
tree_set.add("SFDC");
// Display TreeSet
System.out.println("TreeSet: " + tree_set);
// By using comparator() method is to return
// the Comparator
Comparator com = tree_set.comparator();
// Display Comparator
System.out.println("tree_set.comparator(): " + com);
}
}

Output

输出量

TreeSet: [C, C++, JAVA, PHP, SFDC]
tree_set.comparator(): null

翻译自: https://www.includehelp.com/java/treeset-comparator-method-with-example.aspx

treeset比较器