package com.example.pojo;
public class User {
private String name;
private int age;
private String address;
}
package com.example.dao;
import com.example.pojo.User;
/**
* 数据访问层接口
*/
public interface UserMapper {
//导入用户信息
int insertUser(User user);
}
package com.example.dao;
import com.example.pojo.User;
/**
* 数据访问层的实现类
*/
public class UserMapperImpl implements UserMapper{
//模拟用户信息导入
@Override
public int insertUser(User user) {
System.out.println("用户: " + user.getName() + ", 导入成功!");
return 1;
}
}
package com.example.Service;
import com.example.pojo.User;
/**
* 业务逻辑层接口
*/
public interface UserService {
//导入用户数据的功能
int insertUser(User user);
}
package com.example.Service.impl;
import com.example.Service.UserService;
import com.example.dao.UserMapper;
import com.example.dao.UserMapperImpl;
import com.example.pojo.User;
/**
* 业务逻辑层实现类
*/
public class UserServiceImpl implements UserService {
//数据访问层接口指向数据访问层实现类
UserMapper userMapper = new UserMapperImpl();
@Override
public int insertUser(User user) {
return userMapper.insertUser(user);
}
}
package com.example.controller;
import com.example.Service.UserService;
import com.example.Service.impl.UserServiceImpl;
import com.example.pojo.User;
/**
* 界面层
*/
public class UserController {
//业务逻辑层接口指向业务逻辑层实现类
UserService userService = new UserServiceImpl();
public int insertUser(User user){
return userService.insertUser(user);
}
}
package com.example.test;
import com.example.controller.UserController;
import com.example.pojo.User;
import org.junit.Test;
public class TestInsert {
//测试非Spring框架的简单三层架构
@Test
public void testInsertUser(){
UserController userController = new UserController();
int num = userController.insertUser(new User("荷包蛋", 20, "黑河"));
if(num == 1){
System.out.println("非Spring框架的简单三层架构,运行成功!");
}else{
System.out.println("非Spring框架的简单三层架构,运行失败!");
}
}
}
用户: 荷包蛋, 导入成功!
Spring接管下的简单三层架构,运行成功!
Process finished with exit code 0
测试分析
层级变化:界面层 --> 业务逻辑层 --> 数据访问层 --> 业务逻辑层 --> 界面层
对象访问的变化:界面层对象 --> 业务逻辑层接口指向业务逻辑层实现类 --> 数据访问层接口指向数据访问层实现类 --> 数据访问层实现类完成对数据的操作
方法调用变化:界面层对象的insertUser(User u) --> 业务逻辑层实现类的insertUser(User u) --> 数据访问层实现类的insertUser(User u)
对传统三层项目构建的修改:由上述测试分析中"对象访问的变化可知",需要用到的实现类有:UserController,UserServiceImpl,UserMapperImpl
在Spring接管下,需要在bean工厂中,注册上述实体类的对象,将原先需要程序员手动创建管理的对象交给Spring框架去接手管理
//此时的业务逻辑层实现类:不再手动创建数据访问层的对象,交给Spring容器来管理,新增:setter方法和无参构造函数
package com.example.Service.impl;
import com.example.Service.UserService;
import com.example.dao.UserMapper;
import com.example.pojo.User;
/**
* 业务逻辑层实现类
*/
public class UserServiceImpl implements UserService {
//数据访问层接口指向数据访问层实现类
public UserMapper userMapper;
public void setUserMapper(UserMapper userMapper) {
this.userMapper = userMapper;
}
public UserServiceImpl() {
}
@Override
public int insertUser(User user) {
return userMapper.insertUser(user);
}
}
package com.example.controller;
import com.example.Service.UserService;
import com.example.pojo.User;
/**
* 界面层
*/
public class UserController {
//业务逻辑层接口指向业务逻辑层实现类
UserService userService;
public void setUserService(UserService userService) {
this.userService = userService;
}
public UserController() {
}
public int insertUser(User user){
return userService.insertUser(user);
}
}
<?xml version="1.0" encoding="UTF-8"?>
package com.example.test;
import com.example.controller.UserController;
import com.example.pojo.User;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class TestInsert {
//测试Spring接管下的简单三层架构
@Test
public void testInsertUser(){
//创建Spring容器
ApplicationContext applicationContext = new ClassPathXmlApplicationContext("applicationContext.xml");
//取出界面层对象
UserController uController = (UserController) applicationContext.getBean("uController");
//调用界面层对象方法
int num = uController.insertUser(new User("荷包蛋", 20, "黑河"));
if(num == 1){
System.out.println("Spring接管下的简单三层架构,运行成功!");
}else{
System.out.println("Spring接管下的简单三层架构,运行失败!");
}
}
}
用户: 荷包蛋, 导入成功!
Spring接管下的简单三层架构,运行成功!
Process finished with exit code 0
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