Java 中 Arraylist 升降排序

Java 中 Arraylist 升降排序

這裏給出一個例子，在JAVA中對Arraylist的排序方式。

import java.util.ArrayList; 
import java.util.Collections; 
/** 
 * 
 * Java program to demonstrate How to sort ArrayList in Java in both ascending 
 * and descending order by using core Java libraries.
 * 
 * @author Javin
 */ 
public class CollectionTest {


    public static void main(String args[]) {

        //Creating and populating ArrayList in Java for Sorting 
        ArrayList<String> unsortedList = new ArrayList<String>();

        unsortedList.add("Java"); 
        unsortedList.add("C++"); 
        unsortedList.add("J2EE");

        System.err.println("unsorted ArrayList in Java : " + unsortedList);

        //ArrayList升序排列
        Collections.sort(unsortedList); 
        System.out.println("Sorted ArrayList in Java - Ascending order : " + unsortedList);

        //ArrayList降序排列
        Collections.sort(unsortedList, Collections.reverseOrder()); 
        System.err.println("Sorted ArrayList in Java - Descending order : " + unsortedList); 
    } 
}

Output: unsorted ArrayList in Java : [Java, C++, J2EE]
Sorted ArrayList in Java - Ascending order : [C++, J2EE, Java]
Sorted ArrayList in Java - Descending order : [Java, J2EE, C++]