Java实现员工按姓氏排序后输出指定格式表格的问题求解

代码修改点 #

• 修正separationDate字段类型：原double类型存在精度风险，改为Integer类型，方便处理未离职员工的0值显示为空
• 调整字段格式化规则：统一每列占位宽度，保证表格对齐
• 新增表格表头、分隔线打印逻辑，符合标准表格输出要求
• 保留原按姓氏+名字排序的逻辑，仅调整输出格式

完整可运行代码 #

import java.util.Arrays;
import java.util.Comparator;
import java.util.List;
import java.util.function.Function;

public class EmployeeSort {
    public static void main(String[] args) {
        Employee[] employees = {
                new Employee("John","Johnson","Manager",20161231),
                new Employee("Tou","Xiong","Software Engineer",20161005),
                new Employee("Michaela", "Michaelson", "District Manager", 20151219),
                new Employee("Jake","Jacobson","Programmer",0),
                new Employee("Jackquelyn", "Jackson", "DBA",0),
                new Employee("Sally","Webber","Web Developer",20151218)
        };

        List<Employee> list = Arrays.asList(employees);

        // 定义排序规则：先按姓氏，再按名字
        Function<Employee, String> byFirstName = Employee::getFirstName;
        Function<Employee, String> byLastName = Employee::getLastName;
        Comparator<Employee> lastThenFirst = Comparator.comparing(byLastName).thenComparing(byFirstName);

        // 打印排序后的表格
        System.out.println("按姓氏升序排序的员工列表：");
        // 打印表头
        System.out.printf("%-18s %-22s %s%n", "姓名", "职位", "离职日期");
        // 打印分隔线
        System.out.println("----------------------------------------------------");
        // 排序后逐行打印
        list.stream()
                .sorted(lastThenFirst)
                .forEach(System.out::println);
    }
}

class Employee {
    private String firstName;
    private String lastName;
    private String department;
    // 改为Integer类型处理空值
    private Integer separationDate;

    public Employee(String firstName, String lastName, String department, Integer separationDate) {
        this.firstName = firstName;
        this.lastName = lastName;
        this.department = department;
        this.separationDate = separationDate;
    }

    public String getFirstName() {
        return firstName;
    }

    public void setFirstName(String firstName) {
        this.firstName = firstName;
    }

    public String getLastName() {
        return lastName;
    }

    public void setLastName(String lastName) {
        this.lastName = lastName;
    }

    public String getDepartment() {
        return department;
    }

    public void setDepartment(String department) {
        this.department = department;
    }

    public Integer getSeparationDate() {
        return separationDate;
    }

    public void setSeparationDate(Integer separationDate) {
        this.separationDate = separationDate;
    }

    public String getName() {
        return String.format("%s %s", getFirstName(), getLastName());
    }

    @Override
    public String toString() {
        // 处理离职日期为0的情况显示为空
        String dateStr = separationDate == 0 ? "" : String.valueOf(separationDate);
        return String.format("%-18s %-22s %s", getName(), getDepartment(), dateStr);
    }
}

输出示例 #

按姓氏升序排序的员工列表：
姓名               职位                   离职日期
----------------------------------------------------
Jackquelyn Jackson DBA                    
Jake Jacobson      Programmer             
John Johnson       Manager                20161231
Michaela Michaelson District Manager       20151219
Sally Webber       Web Developer          20151218
Tou Xiong          Software Engineer      20161005

内容的提问来源于stack exchange，提问作者Daniel.grafton