Java8-取List对象中的最大值

原创已于 2023-02-21 11:03:02 修改 · 2.9k 阅读

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于 2022-04-18 17:25:26 首次发布

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这段代码展示了如何使用Java 8的Stream API从Employee对象列表中提取年龄，将其转换为Double并找到最大值。员工的年龄以字符串形式存储，首先通过Double.parseDouble进行转换。此外，注释中还提供了另一种方法，使用Integer.parseInt进行转换并找到最大值。

public class Test {

    public static void main(String[] args) {
        List<Employee> employees = Arrays.asList(
                new Employee(1,"刘德华","88.8"),
                new Employee(2,"张学友","70"),
                new Employee(3,"黎明","90.5"),
                new Employee(4,"郭富城","66"));
        OptionalDouble sum = employees.stream().map(Employee::getAge).mapToDouble(Double::parseDouble).max();
        System.out.println("sum = " + sum.getAsDouble());

        /*OptionalInt sum2 = employees.stream().map(Employee::getAge).mapToInt(Integer::parseInt).max();
        System.out.println("sum = " + sum2.getAsInt());*/
    }
}

package com.nanjing.commonutils;

/**
 * @author yimo
 * @version 1.0
 * @date 2022/4/18 16:45
 */
public class Employee {
    private int id;
    private String name;
    private String age;

    public Employee() {
    }

    public Employee(int id, String name, String age) {
        this.id = id;
        this.name = name;
        this.age = age;
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getAge() {
        return age;
    }

    public void setAge(String age) {
        this.age = age;
    }
}