List操作

来源：互联网发布：vnc server使用的端口编辑：程序博客网时间：2024/06/06 19:16

大部分都是用lambda实现的，在jdk为1.8时才能生效

排序

public class Person {    private String name;    private int age;    public Person(String name, int age) {        setAge(age);        setName(name);    }    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;    }}

import java.util.ArrayList;import java.util.List;public class ListSort{    public static void main(String[] args) {        Person p1 = new Person("Jack", 12);        Person p2 = new Person("Nick", 11);        Person p3 = new Person("Bob", 14);        Person p4 = new Person("Lucy", 18);        List<Person> sortList = new ArrayList<Person>();        sortList.add(p1);        sortList.add(p2);        sortList.add(p3);        sortList.add(p4);        //顺序        sortList.sort((a, b) -> a.getAge() - b.getAge());        //倒序        //sortList.sort((a, b) -> b.getAge() - a.getAge());        sortList.forEach(p -> System.out.print(p.getName() + ":" + p.getAge() + '\n'));    }}

打印结果：

Nick:11Jack:12Bob:14Lucy:18

筛选

import java.util.ArrayList;import java.util.List;import java.util.stream.Collectors;public class ListFilter {    public static void main(String[] args) {        Person p1 = new Person("Jack", 12);        Person p2 = new Person("Nick", 11);        Person p3 = new Person("Bob", 14);        Person p4 = new Person("Lucy", 18);        List<Person> filterList = new ArrayList<Person>();        filterList.add(p1);        filterList.add(p2);        filterList.add(p3);        filterList.add(p4);        List<Person> ageFilter = filterList.stream().filter(p -> p.getAge() > 13).collect(Collectors.toList());        List<Person> nameFilter = filterList.stream().filter(p -> p.getName().equals("Jack")).collect(Collectors.toList());        System.out.println("ageFilter:");        ageFilter.forEach(p -> System.out.print(p.getName() + ":" + p.getAge() + '\n'));        System.out.println("nameFilter:");        nameFilter.forEach(p -> System.out.print(p.getName() + ":" + p.getAge() + '\n'));    }}

输出：

ageFilter:Bob:14Lucy:18nameFilter:Jack:12

截取

import java.util.ArrayList;import java.util.List;public class ListSubList {    public static void main(String[] args) {        Person p1 = new Person("Jack", 12);        Person p2 = new Person("Nick", 11);        Person p3 = new Person("Bob", 14);        Person p4 = new Person("Lucy", 18);        List<Person> subList = new ArrayList<Person>();        subList.add(p1);        subList.add(p2);        subList.add(p3);        subList.add(p4);        //subList(indexStart, indexEnd);indexStart开始位置，包含。indexEnd结束位置，不包含        subList = subList.subList(1, 4);        subList.forEach(p -> System.out.print(p.getName() + ":" + p.getAge() + '\n'));    }}

输出

Nick:11Bob:14Lucy:18

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