比较器Comparator与自定义排序

package com.yin2na.example;

import java.util.List;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;

public class SortTest
{
public static void main(String[] args)
{
List<Student> list = new ArrayList<Student>();
list.add(new Student("yin2na", 24));
list.add(new Student("susanbear", 22));
list.add(new Student("doing", 20));
list.add(new Student("Jesus", 2011));

System.out.println("原顺序：");
for(Student stu : list)
{
System.out.println(stu);
}

System.out.println("默认顺序：");
Collections.sort(list);
for(Student stu : list)
{
System.out.println(stu);
}

System.out.println("反序：");
Collections.sort(list, Collections.reverseOrder());//Collections.reverseOrder()返回一个比较器Comparator
for(Student stu : list)
{
System.out.println(stu);
}

System.out.println("自定义顺序：");
Collections.sort(list, new Comparator<Student>(){//匿名内部类
public int compare(Student stu1, Student stu2)
{
if (stu1.getName().length() > stu2.getName().length())
{
return 1;
}
else if (stu1.getName().length() < stu2.getName().length())
{
return -1;
}
else
{
return 0;
}
}
});
for(Student stu : list)
{
System.out.println(stu);
}

}
}

class Student implements Comparable<Student>
{
private String name;
private int age;

public Student(String name, int age)
{
this.name = name;
this.age = age;
}

public String getName()
{
return name;
}

public int compareTo(Student stu)
{
if (this.age > stu.age)
{
return 1;
}
else if (this.age < stu.age)
{
return -1;
}
else
{
return 0;
}
}

@Override
public String toString()
{
return name + " is " + age;
}
}