Bean：

    1. package com.way.pojo;
    3. public class Employee {
    4.     private Integer id;
    5.     private String lastName;
    6.     private String email;
    7.     //1 male, 0 female
    8.     private Integer gender;
    10.     public Integer getId() {
    11.         return id;
    12.     }
    14.     public void setId(Integer id) {
    15.         this.id = id;
    16.     }
    18.     public String getLastName() {
    19.         return lastName;
    20.     }
    22.     public void setLastName(String lastName) {
    23.         this.lastName = lastName;
    24.     }
    26.     public String getEmail() {
    27.         return email;
    28.     }
    30.     public void setEmail(String email) {
    31.         this.email = email;
    32.     }
    34.     public Integer getGender() {
    35.         return gender;
    36.     }
    38.     public void setGender(Integer gender) {
    39.         this.gender = gender;
    40.     }
    42.     public Employee(Integer id, String lastName, String email, Integer gender) {
    43.         super();
    44.         this.id = id;
    45.         this.lastName = lastName;
    46.         this.email = email;
    47.         this.gender = gender;
    48.     }
    49.     public Employee() { }
    50. }

    dao：

    1. package com.way.dao;
    3. import com.way.pojo.Employee;
    4. import org.springframework.stereotype.Repository;
    6. import java.util.Collection;
    7. import java.util.HashMap;
    8. import java.util.Map;
    10. @Repository
    11. public class EmployeeDao {
    12.     private static Map<Integer, Employee> employees = null;
    13.     static{
    14.         employees = new HashMap<Integer, Employee>();
    15.         employees.put(1001, new Employee(1001, "E-AA", "aa@163.com", 1));
    16.         employees.put(1002, new Employee(1002, "E-BB", "bb@163.com", 1));
    17.         employees.put(1003, new Employee(1003, "E-CC", "cc@163.com", 0));
    18.         employees.put(1004, new Employee(1004, "E-DD", "dd@163.com", 0));
    19.         employees.put(1005, new Employee(1005, "E-EE", "ee@163.com", 1));
    20.     }
    21.     private static Integer initId = 1006;
    23.     public void save(Employee employee){
    24.         if(employee.getId() == null){
    25.             employee.setId(initId++);
    26.         }
    27.         employees.put(employee.getId(), employee);
    28.     }
    30.     public Collection<Employee> getAll(){
    31.         return employees.values();
    32.     }
    34.     public Employee get(Integer id){
    35.         return employees.get(id);
    36.     }
    38.     public void delete(Integer id){
    39.         employees.remove(id);
    40.     }
    41. }