订购类（Ordering Class）

订购可以看作是一个丰富的比较器，具有增强的链接功能，多种实用方法，多种类型的排序功能等。

Class 声明 (Class Declaration)

以下是com.google.common.collect.Ordering《T》类的声明 -

@GwtCompatible
public abstract class Ordering<T>
   extends Object
      implements Comparator<T>

Class Methods

方法继承 (Methods Inherited)

该类继承以下类中的方法 -

• java.lang.Object

订购类示例

使用您选择的任何编辑器在C:/》 Guava.创建以下java程序C:/》 Guava.

GuavaTester.java

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import com.google.common.collect.Ordering;
public class GuavaTester {
   public static void main(String args[]) {
      List<Integer> numbers = new ArrayList<Integer>();
      numbers.add(new Integer(5));
      numbers.add(new Integer(2));
      numbers.add(new Integer(15));
      numbers.add(new Integer(51));
      numbers.add(new Integer(53));
      numbers.add(new Integer(35));
      numbers.add(new Integer(45));
      numbers.add(new Integer(32));
      numbers.add(new Integer(43));
      numbers.add(new Integer(16));
      Ordering ordering = Ordering.natural();
      System.out.println("Input List: ");
      System.out.println(numbers);		
      Collections.sort(numbers,ordering );
      System.out.println("Sorted List: ");
      System.out.println(numbers);
      System.out.println("======================");
      System.out.println("List is sorted: " + ordering.isOrdered(numbers));
      System.out.println("Minimum: " + ordering.min(numbers));
      System.out.println("Maximum: " + ordering.max(numbers));
      Collections.sort(numbers,ordering.reverse());
      System.out.println("Reverse: " + numbers);
      numbers.add(null);
      System.out.println("Null added to Sorted List: ");
      System.out.println(numbers);		
      Collections.sort(numbers,ordering.nullsFirst());
      System.out.println("Null first Sorted List: ");
      System.out.println(numbers);
      System.out.println("======================");
      List<String> names = new ArrayList<String>();
      names.add("Ram");
      names.add("Shyam");
      names.add("Mohan");
      names.add("Sohan");
      names.add("Ramesh");
      names.add("Suresh");
      names.add("Naresh");
      names.add("Mahesh");
      names.add(null);
      names.add("Vikas");
      names.add("Deepak");
      System.out.println("Another List: ");
      System.out.println(names);
      Collections.sort(names,ordering.nullsFirst().reverse());
      System.out.println("Null first then reverse sorted list: ");
      System.out.println(names);
   }
}

验证结果

使用javac编译器编译类如下 -

C:\Guava>javac GuavaTester.java

现在运行GuavaTester来查看结果。

C:\Guava>java GuavaTester

看到结果。

Input List: 
[5, 2, 15, 51, 53, 35, 45, 32, 43, 16]
Sorted List: 
[2, 5, 15, 16, 32, 35, 43, 45, 51, 53]
======================
List is sorted: true
Minimum: 2
Maximum: 53
Reverse: [53, 51, 45, 43, 35, 32, 16, 15, 5, 2]
Null added to Sorted List: 
[53, 51, 45, 43, 35, 32, 16, 15, 5, 2, null]
Null first Sorted List: 
[null, 2, 5, 15, 16, 32, 35, 43, 45, 51, 53]
======================
Another List: 
[Ram, Shyam, Mohan, Sohan, Ramesh, Suresh, Naresh, Mahesh, null, Vikas, Deepak]
Null first then reverse sorted list: 
[Vikas, Suresh, Sohan, Shyam, Ramesh, Ram, Naresh, Mohan, Mahesh, Deepak, null]