Java中List的排序方法

java

方法一:实现Comparable接口

package com.java.test;

public class Person implements Comparable<Person> {

private String name;

private Integer age;

public Person() {

}

public Person(String name, Integer age) {

this.name = name;

this.age = age;

}

public String getName() {

return name;

}

public void setName(String name) {

this.name = name;

}

public Integer getAge() {

return age;

}

public void setAge(Integer age) {

this.age = age;

}

@Override

public int compareTo(Person o) {

return age.compareTo(o.getAge());//正序

     //return o.getAge().compareTo(age);//倒序

} }

package com.java.test;

import java.util.ArrayList;

import java.util.Collections;

import java.util.List;

public class PersonTest {

public static void main(String[] args) {

List<Person> list = new ArrayList<Person>();

list.add(new Person("E", 16));

list.add(new Person("C", 14));

list.add(new Person("A", 12));

list.add(new Person("B", 13));

list.add(new Person("D", 15));

for (Person person : list) {

System.out.println(person.getAge());

}

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

Collections.sort(list);

for (Person person : list) {

System.out.println(person.getAge());

}

}

}

方法二:调用Collections.sort(List<T> list, Comparator<? super T> c),定义Comparator

package com.java.test;

public class Person {

private String name;

private Integer age;

public Person() {

}

public Person(String name, Integer age) {

this.name = name;

this.age = age;

}

public String getName() {

return name;

}

public void setName(String name) {

this.name = name;

}

public Integer getAge() {

return age;

}

public void setAge(Integer age) {

this.age = age;

}

}

package com.java.test;

import java.util.ArrayList;

import java.util.Collections;

import java.util.Comparator;

import java.util.List;

public class PersonTest {

public static void main(String[] args) {

List<Person> list = new ArrayList<Person>();

list.add(new Person("E", 16));

list.add(new Person("C", 14));

list.add(new Person("A", 12));

list.add(new Person("B", 13));

list.add(new Person("D", 15));

for (Person person : list) {

System.out.println(person.getAge());

}

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

Collections.sort(list, new Comparator<Person>() {

@Override

public int compare(Person o1, Person o2) {

return o1.getAge().compareTo(o2.getAge());//正序
         //return o2.getAge().compareTo(o1.getAge());//倒序

}

});

for (Person person : list) {

System.out.println(person.getAge());

}

}

}

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