[开发工具]Java8 stream().map() 修改元素

Java8 stream().map() 是一个中间操作，可实现对元素进行修改，这意味着它返回Stream对象。

代码实现：

package com.collectStream;

import lombok.Data;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Comparator;
import java.util.List;
import java.util.stream.Collectors;

public class TestStreamMap {

    public static void sorted() {

        List<Integer> list = Arrays.asList(5, 4, 3, 2, 7, 1, 6, 0, 8);
        List<Integer> newList = list.stream().map(x -> x + 1).collect(Collectors.toList());

        System.out.println("原始数组:" + list);
        System.out.println("自增一后:" + newList);

        System.out.println();

        List<Student> personList = new ArrayList<>();
        personList.add(new Student("张三", 16, 181));
        personList.add(new Student("李四", 17, 180));
        personList.add(new Student("王五", 16, 179));
        personList.add(new Student("张明", 18, 177));
        personList.add(new Student("李威", 16, 190));
        personList.add(new Student("王鹏", 15, 188));
        personList.add(new Student("王莉", 17, 177));

        //筛选年龄大于15岁，年龄升序，并定义为合格
        List<Student> qualifiedPList = personList.stream()
                .filter(student -> student.getAge() > 15)
                .sorted(Comparator.comparingInt(Student::getAge))
                .map(student -> {
                    student.setFlag("合格");
                    return student;
                })
                .collect(Collectors.toList());


        printStudents(qualifiedPList);

    }

    public static void printStudents(List<Student> StudentList) {
        System.out.println("【姓名】\t【年龄】\t【身高】\t【审核】");
        System.out.println("-------------------------------");
        StudentList.forEach(s -> System.out.println(s.toString()));
        System.out.println(" ");
    }


    public static void main(String[] args) {
        sorted();
    }

}

@Data
class Student {
    private String name;
    private Integer age;
    private Integer height;
    private String flag;

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

    public String toString() {
        String info = String.format("%s\t\t%s\t\t%s\t\t%s\t\t\t", this.name, this.age.toString(), this.height.toString(), this.getFlag());
        return info;
    }
}

打印输出：

原始数组:[5, 4, 3, 2, 7, 1, 6, 0, 8]
自增一后:[6, 5, 4, 3, 8, 2, 7, 1, 9]

【姓名】	【年龄】	【身高】	【审核】
-------------------------------
张三		16		181		合格			
王五		16		179		合格			
李威		16		190		合格			
李四		17		180		合格			
王莉		17		177		合格			
张明		18		177		合格