java学习笔记13--比较器(Comparable、Comparator) - JAVA

Compartor

如果一个类已经开放完成，但是在此类建立的初期并没有实现Comparable接口，此时肯定是无法进行对象排序操作的，所以为了解决这一的问题，java又定义了另一个比较器的操作接口 Comparator 此接口定义在java.util包中，接口定义如下：

public interface Comparator{

public int compare(T o1，T o2);

boolean equals(Object obj);

}

MyComparator.java

[java package com.itmyhome;

import java.util.Comparator;

public class MyComparator implements Comparator { //实现比较器

@Override
public int compare(Student stu1, Student stu2) {
// TODO Auto-generated method stub
if(stu1.getAge()>stu2.getAge()){
return 1;
}else if(stu1.getAge() return -1;
}else{
return 0;
}
}

}

package com.itmyhome;

import java.util.Comparator;

public class MyComparator implements Comparator { //实现比较器

@Override
public int compare(Student stu1, Student stu2) {
// TODO Auto-generated method stub
if(stu1.getAge()>stu2.getAge()){
return 1;
}else if(stu1.getAge() return -1;
}else{
return 0;
}
}

}

[java] package com.itmyhome;

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

class Student {
private String name;
private int age;

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

public String toString(){
return "姓名："+this.name+", 年龄："+this.age;
}

public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
}

public class T {
public static void main(String[] args) throws Exception{
Student stu[] = {new Student("张三",23)
,new Student("李四",26)
,new Student("王五",22)};
Arrays.sort(stu,new MyComparator()); //对象数组进行排序操作

List list = new ArrayList();
list.add(new Student("zhangsan",31));
list.add(new Student("lisi",30));
list.add(new Student("wangwu",35));
Collections.sort(list,new MyComparator()); //List集合进行排序操作

for (int i = 0; i < stu.length; i++) {
Student s = stu[i];
System.out.println(s);
}

System.out.println("*********");

for (int i=0;i Student s = list.get(i);
System.out.println(s);
}
}
}

package com.itmyhome;

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

class Student {
private String name;
private int age;

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

public String toString(){
return "姓名："+this.name+", 年龄："+this.age;
}

public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
}

public class T {
public static void main(String[] args) throws Exception{
Student stu[] = {new Student("张三",23)
,new Student("李四",26)
,new Student("王五",22)};
Arrays.sort(stu,new MyComparator()); //对象数组进行排序操作

List list = new ArrayList();
list.a

java学习笔记13--比较器(Comparable、Comparator) (四)