JAVA集合解决问题

Question

利用JAVA知识，实现对职工信息的输出，请各位会的帮帮忙，谢谢啦！

Answer 1

Employee 类

public class Employee {
    private int id;
    private String name;
    private char sex;
    private double salary;

    public Employee(int id, String name, char sex, double salary) {
        this.id = id;
        this.name = name;
        this.sex = sex;
        this.salary = salary;
    }

    public int getId() {
      return this.id;
    }

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

    public String getName() {
      return this.name;
    }

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

    public char getSex() {
      return this.sex;
    }

    public void setSex(char sex) {
      this.sex = sex;
    }

    public double getSalary() {
      return this.salary;
    }

    public void setSalary(double salary) {
      this.salary = salary;
    }

    @Override
    public String toString() {
        return "Employee{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", sex=" + sex +
                ", salary=" + salary +
                '}';
    }
}

主程序

import java.util.*;

public class Main {
    public static void main(String[] args) {
        // 定义3个Employee对象
        Employee employee1 = new Employee(1, "Tom", 'M', 5000.0);
        Employee employee2 = new Employee(2, "Jerry", 'M', 6000.0);
        Employee employee3 = new Employee(3, "Lucy", 'F', 7000.0);

        // 用Map存储Employee对象
        Map<Integer, Employee> employeeMap = new HashMap<>();
        employeeMap.put(employee1.getId(), employee1);
        employeeMap.put(employee2.getId(), employee2);
        employeeMap.put(employee3.getId(), employee3);

        // 用List存储Employee对象
        List<Employee> employeeList = new ArrayList<>();
        employeeList.add(employee1);
        employeeList.add(employee2);
        employeeList.add(employee3);

        // 用Set存储Employee对象
        Set<Employee> employeeSet = new HashSet<>();
        employeeSet.add(employee1);
        employeeSet.add(employee2);
        employeeSet.add(employee3);

        // 增加员工
        Employee employee4 = new Employee(4, "Kate", 'F', 8000.0);
        employeeMap.put(employee4.getId(), employee4);
        employeeList.add(employee4);
        employeeSet.add(employee4);

        // 删除员工
        int deleteEmployeeId = 2;
        employeeMap.remove(deleteEmployeeId);
        employeeList.removeIf(e -> e.getId() == deleteEmployeeId);
        employeeSet.removeIf(e -> e.getId() == deleteEmployeeId);

        // 修改员工
        int updateEmployeeId = 3;
        Employee updatedEmployee = employeeMap.get(updateEmployeeId);
        updatedEmployee.setName("Lily");
        employeeList.stream()
                .filter(e -> e.getId() == updateEmployeeId)
                .findFirst()
                .ifPresent(e -> e.setName("Lily"));
        employeeSet.stream()
                .filter(e -> e.getId() == updateEmployeeId)
                .findFirst()
                .ifPresent(e -> e.setName("Lily"));

        // 查询员工
        int queryEmployeeId = 1;
        Employee queryEmployee = employeeMap.get(queryEmployeeId);
        System.out.println("Query result of Map: " + queryEmployee);
        employeeList.stream()
                .filter(e -> e.getId() == queryEmployeeId)
                .findFirst()
                .ifPresent(e -> System.out.println("Query result of List: " + e));
        employeeSet.stream()
                .filter(e -> e.getId() == queryEmployeeId)
                .findFirst()
                .ifPresent(e -> System.out.println("Query result of Set: " + e));
    }
}