java中Comparator接口

Comparator接口：有compare(),equals()方法，用于比较对象某个属性的大小。

此时还要用到，数组，将对象 放入数组中。

利用collections.sort()方法来实现对象某个属性的比较。

List list = new ArrayList();
/*通过调用list.add()方法，将对象放到数组里*/
ComparatorClass compare = new ComparatorClass();
Collections.sort(list,compare);

package com.learn.notes;

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

/**
* @ClassName ComparatorTest
* @Description TODO
*
* @author XingZhaohu 1178243325@qq.com
* @date 2016-3-30 下午10:05:09
*/
public class ComparatorTest {

/**
* @Title main
* @Description TODO
* @param args
* @return void
*
* @author XingZhaohu 1178243325@qq.com
* @date 2016-3-30 下午10:05:09
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
Students[] students = new Students[3];

students[0] = new Students("小李子","男",19,110);
students[1] = new Students("苏茉","女",18,111);
students[2] = new Students("天明","男",20,112);

List list = new ArrayList();

for(Students s:students)
list.add(s);

Compares compare = new Compares();
Collections.sort(list,compare);

for(Students ss:(List<Students>)list)
System.out.println(ss.toString());

}

}

/**
*
* @ClassName Person
* @Description TODO
*
* @author XingZhaohu 1178243325@qq.com
* @date 2016-3-30 下午10:40:09
*/
class Person{

private String name;
private String sex;
private int age;

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

public String getName(){
return name;
}

public void setName(String name){
this.name = name;
}

public String getSex(){
return sex;
}

public void setSex(String sex){
this.sex = sex;
}

public int getAge(){
return age;
}

public void setAge(int age){
this.age = age;
}
}

/**
*
* @ClassName Students
* @Description TODO
*
* @author XingZhaohu 1178243325@qq.com
* @date 2016-3-30 下午10:40:20
*/
class Students extends Person{
private int id;

public Students(String name,String sex,int age,int id){
super(name,sex,age);
this.id = id;
}

public void setId(int id){
this.id = id;
}

public int getId(){
return id;
}

public String toString(){
return "name="+super.getName()+" sex="+super.getSex()+" age="+super.getAge()+" id="+this.getId();
}
}

/**
*
* @ClassName Compares
* @Description TODO
*
* @author XingZhaohu 1178243325@qq.com
* @date 2016-3-30 下午10:39:44
*/
class Compares implements Comparator<Students>{

/* (non-Javadoc)
* @see java.util.Comparator#compare(java.lang.Object, java.lang.Object)
*/
@Override
public int compare(Students o1, Students o2) {
// TODO Auto-generated method stub
if(o1.getAge()>o2.getAge())
return 1;
else if(o1.getAge()<o2.getAge())
return -1;
else
return 0;

}

}