引用1:https://blog.csdn.net/sanchan/article/details/70753645

引用2:https://www.ibm.com/developerworks/cn/java/j-lo-java8streamapi/

在Java 8中stream().map()，您可以将对象转换为其他对象。查看以下示例：

1.大写字符串列表

1.1简单的Java示例将Strings列表转换为大写。

TestJava8.java

package com.mkyong.java8;

import java.util.ArrayList;

import java.util.Arrays;

import java.util.List;

import java.util.stream.Collectors;

public class TestJava8 {

    public static void main(String[] args) {

        List<String> alpha = Arrays.asList("a", "b", "c", "d");

        //Before Java8

        List<String> alphaUpper = new ArrayList<>();

        for (String s : alpha) {

            alphaUpper.add(s.toUpperCase());

        }

        System.out.println(alpha); //[a, b, c, d]

        System.out.println(alphaUpper); //[A, B, C, D]

        // Java 8

        List<String> collect = alpha.stream().map(String::toUpperCase).collect(Collectors.toList());

        System.out.println(collect); //[A, B, C, D]

        // Extra, streams apply to any data type.

        List<Integer> num = Arrays.asList(1,2,3,4,5);

        List<Integer> collect1 = num.stream().map(n -> n * 2).collect(Collectors.toList());

        System.out.println(collect1); //[2, 4, 6, 8, 10]

    }

}

2.对象列表 - >字符串列表

2.1 name从staff对象列表中获取所有值。

Staff.java

package com.mkyong.java8;

import java.math.BigDecimal;

public class Staff {

    private String name;

    private int age;

    private BigDecimal salary;

    //...

}