24.10.14

后端：构建一个简单的用户管理接口（CRUD）。
前端：通过Vue Axios调用后端接口展示数据。

public class User {
    private int id;
    private String name;
    private int age;
    private String email;
 
    // 构造函数
    public User(int id, String name, int age, String email) {
        this.id = id;
        this.name = name;
        this.age = age;
        this.email = email;
    }
 
    // Getter和Setter方法
    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 int getAge() {
        return age;
    }
 
    public void setAge(int age) {
        this.age = age;
    }
 
    public String getEmail() {
        return email;
    }
 
    public void setEmail(String email) {
        this.email = email;
    }
 
    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", name='" + name + '\\'' +
                ", age=" + age +
                ", email='" + email + '\\'' +
                '}';
    }
}
import java.util.List;
 
public interface UserManager {
    void addUser(User user);
    void deleteUser(int userId);
    void updateUser(User user);
    User getUserById(int userId);
    List<User> getAllUsers();
}import java.util.ArrayList;
import java.util.List;
 
public class UserManagerImpl implements UserManager {
    private List<User> userList = new ArrayList<>();
 
    @Override
    public void addUser(User user) {
        userList.add(user);
    }
 
    @Override
    public void deleteUser(int userId) {
        userList.removeIf(user -> user.getId() == userId);
    }
 
    @Override
    public void updateUser(User user) {
        for (int i = 0; i < userList.size(); i++) {
            if (userList.get(i).getId() == user.getId()) {
                userList.set(i, user);
                break;
            }
        }
    }
 
    @Override
    public User getUserById(int userId) {
        for (User user : userList) {
            if (user.getId() == userId) {
                return user;
            }
        }
        return null;
    }
 
    @Override
    public List<User> getAllUsers() {
        return new ArrayList<>(userList);
    }
}public class UserManagerTest {
    public static void main(String[] args) {
        UserManager userManager = new UserManagerImpl();
 
        // 添加用户
        userManager.addUser(new User(1, "Alice", 30, "alice@example.com"));
        userManager.addUser(new User(2, "Bob", 25, "bob@example.com"));
 
        // 查询所有用户
        System.out.println("All Users: " + userManager.getAllUsers());
 
        // 更新用户信息
        User user = userManager.getUserById(1);
        if (user != null) {
            user.setAge(31);
            userManager.updateUser(user);
        }
 
        // 查询更新后的用户信息
        System.out.println("Updated User: " + userManager.getUserById(1));
 
        // 删除用户
        userManager.deleteUser(2);
 
        // 查询删除后的所有用户
        System.out.println("Users after deletion: " + userManager.getAllUsers());
    }
}