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三层架构
1、Dao层
全称为Data Access Object，负责于数据库进行联络，完成增删查改的功能。提供接口给Service层。
2、Service层
调用Dao层提供的接口，业务处理，为Controller层提供接口。
3、Controller层
负责请求转发，接收用户传来的参数，通过调用Service层提供的接口，实现将数据转发给Service层处理。接收Service的返回值，再转发给用户。
简易登录功能
需求： 通过Spring框架，实现与数据库连接，在控制台输入用户名和密码，对用户进行校验、登陆、验证，成功返回“success”，失败返回“error”。
项目整体目录结构
其中libs目录包含了spring框架所需要的jar依赖包和jdbc包 
数据库信息
entity实体类User:
package com.yancy.entity;
public class User {
private String userName;
private String passWord;
public String getUserName() {
return userName;
}
public void setUserName(String userName) {
this.userName = userName;
}
public String getPassWord() {
return passWord;
}
public void setPassWord(String passWord) {
this.passWord = passWord;
}
}
Controller层代码
package com.yancy.controller;
import com.yancy.entity.User;
import com.yancy.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
@Controller
public class UserController {
@Autowired
UserService userService;
public String userLogin(User user) {
Boolean result = userService.userLogin(user);
if(result)
return "success";
else
return "erro";
}
}
Srevice层代码
UserService接口
package com.yancy.service;
import com.yancy.entity.User;
public interface UserService {
public boolean userLogin(User user);
}
UserService接口实现类 UserServiceImpl
package com.yancy.service.impl;
import com.yancy.dao.UserDao;
import com.yancy.entity.User;
import com.yancy.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
@Service
public class UserServiceImpl implements UserService {
@Autowired
UserDao userDao;
@Override
public boolean userLogin(User user) {
User sqlUser = userDao.userLogin(user);
if((sqlUser.getUserName().equals(user.getUserName())) && (sqlUser.getPassWord().equals( user.getPassWord()))) return true;
return false;
}
}
Dao层代码
UserDao接口:UserDao
package com.yancy.dao;
import com.yancy.entity.User;
public interface UserDao {
public User userLogin(User user);
}
UserDao接口的实现类：UserDaoImpl
package com.yancy.dao.impl;
import com.yancy.dao.UserDao;
import com.yancy.entity.User;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.core.RowMapper;
import org.springframework.stereotype.Repository;
@Repository
public class UserDaoImpl implements UserDao {
@Autowired
JdbcTemplate jdbcTemplate;
@Override
public User userLogin(User user) {
String sql="select * from user where userName=?";
RowMapper rowMapper=new BeanPropertyRowMapper(User.class);
User resUser= jdbcTemplate.queryForObject(sql,rowMapper,user.getUserName());
return resUser;
}
}
配置文件bean.xml(在src的目录下，不在com下)
测试类Main
import com.yancy.controller.UserController;
import com.yancy.entity.User;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.jdbc.core.JdbcTemplate;
import java.util.Scanner;
public class Main {
public static void main(String[] args) {
/* ApplicationContext applicationContext = new ClassPathXmlApplicationContext("bean.xml");
JdbcTemplate jdbcTemplate = (JdbcTemplate) applicationContext.getBean("jdbcTemplate");
System.out.println(jdbcTemplate);*/
ApplicationContext applicationContext = new ClassPathXmlApplicationContext("bean.xml");
UserController userController = (UserController) applicationContext.getBean("userController");
User user = new User();
Scanner in = new Scanner(System.in);
System.out.printf("请输入用户名：");
user.setUserName(in.next());
System.out.printf("请输入密码：");
user.setPassWord(in.next());
System.out.println(userController.userLogin(user));
}
}
运行结果
运行Main类中主函数 输入数据库中存在的用户信息：  输入错误信息： 
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