lambda常用操作

package com.wlf.jdk8test;

import com.wlf.entity.Person;

import javax.swing.text.html.parser.Entity;
import java.util.Arrays;
import java.util.Comparator;
import java.util.List;
import java.util.stream.Collectors;

/**
 * @author LifengWang
 * @create 2020-07-05  23:29
 */
public class Test {


    public static void main(String[] args) {

        Person p1=new Person("zhagnsan",20);
        Person p2=new Person("lisi",40);
        Person p3=new Person("wangwu",60);
        Person p4=new Person("zhaoliu",25);
        Person p5=new Person("tianqi",30);
        Person p6=new Person("niuba",10);
        Person p7=new Person("niuba",10); //去重添加


        List<Person>   list= Arrays.asList(p1,p2,p3,p4,p5,p6,p7);

        // 获取所有名字信息
        List<String> list1 = list.stream().map(Person::getName).collect(Collectors.toList());
        list1.forEach(System.out::println);
        //排序年龄
        List<Person> list2 = list.stream().sorted(Comparator.comparingInt(Person::getAge)).collect(Collectors.toList());
        list2.forEach(System.out::println);

        // 排序操作  默认排序和倒序
        List<Person> list3 = list.stream().sorted(Comparator.comparingInt(Person::getAge).reversed()).collect(Collectors.toList());
        list3.forEach(System.out::println);

       // 过滤Filter
        List<Person> list4 = list.stream().filter(person -> person.getAge() > 30).collect(Collectors.toList());
        list4.forEach(System.out::println);
        // 获取最大年龄
        Integer maxAge = list.stream().map(person -> person.getAge()).max(Integer::compareTo).get();
        System.out.println(maxAge);
        // 获取最小年龄
        Integer minAge = list.stream().map(person -> person.getAge()).min(Integer::compareTo).get();
        System.out.println(minAge);

       //获取数量
        long count = list.stream().map(Person::getAge).count();
        System.out.println(count);
        // 获取平均年龄
        double asDouble = list.stream().mapToInt(Person::getAge).average().getAsDouble();
        System.out.println(asDouble);
        //获取第一个对象
        Person person = list.stream().findFirst().get();
        System.out.println(person);
        // 将名字都转换为大写
        List<String> collect = list.stream().map(Person::getName).map(String::toUpperCase).collect(Collectors.toList());
        collect.forEach(System.out::println);
        // 忽略第一个调数据
        List<Person> list7 = list.stream().sorted(Comparator.comparingInt(Person::getAge).reversed()).skip(1).collect(Collectors.toList());
        list7.forEach(System.out::println);
        // 去重
        List<Person> list8 = list.stream().distinct().collect(Collectors.toList());
        list8.forEach(System.out::println);



    }

}

本文地址：https://blog.csdn.net/wang_lifeng/article/details/107147864