1.准备工作

和传统 CRUD 一样，实现对员工信息的增删改查。

1.搭建环境
2.准备实体类

实体类：

package com.atguigu.rest.bean;
/**
 * @author Dxkstart
 * @create 2021-11-09-18:58
 */
public class Employee {
    private Integer id;
    private String lastName;
    private String email;
    //1 male, 0 female
    private Integer gender;
    public Integer getId() {
        return id;
    }
    public void setId(Integer id) {
        this.id = id;
    }
    public String getLastName() {
        return lastName;
    }
    public void setLastName(String lastName) {
        this.lastName = lastName;
    }
    public String getEmail() {
        return email;
    }
    public void setEmail(String email) {
        this.email = email;
    }
    public Integer getGender() {
        return gender;
    }
    public void setGender(Integer gender) {
        this.gender = gender;
    }
    public Employee(Integer id, String lastName, String email, Integer
            gender) {
        super();
        this.id = id;
        this.lastName = lastName;
        this.email = email;
        this.gender = gender;
    }
    public Employee() {
    }
}

    <br />3.准备到模拟数据

dao（里面包含crud方法）：

package com.atguigu.rest.dao;

import com.atguigu.rest.bean.Employee;
import org.springframework.stereotype.Repository;

import java.util.Collection;
import java.util.HashMap;
import java.util.Map;

/**
 * @author Dxkstart
 * @create 2021-11-09-19:00
 */
@Repository
public class EmployeeDao {

    private static Map<Integer, Employee> employees = null;

    static {
        employees = new HashMap<Integer, Employee>();

        employees.put(1001, new Employee(1001, "E-AA", "aa@163.com", 1));
        employees.put(1002, new Employee(1002, "E-BB", "bb@163.com", 1));
        employees.put(1003, new Employee(1003, "E-CC", "cc@163.com", 0));
        employees.put(1004, new Employee(1004, "E-DD", "dd@163.com", 0));
        employees.put(1005, new Employee(1005, "E-EE", "ee@163.com", 1));
    }

    private static Integer initId = 1006;

    //添加、修改
    public void save(Employee employee) {
        if (employee.getId() == null) {
            employee.setId(initId++);
        }
        employees.put(employee.getId(), employee);
    }

    //查询所有员工信息
    public Collection<Employee> getAll() {
        return employees.values();
    }

    public Employee get(Integer id) {
        return employees.get(id);
    }

    public void delete(Integer id) {
        employees.remove(id);
    }
}