0️⃣概述
👾SSM与三层架构对应关系
SpringMVC —— 表示层(controller、view)
Spring —— 业务逻辑层(service)
MyBatis —— 数据访问层(dao、pojo)

👾配置文件
spring-config.xml —— Spring容器,管理service和dao等对象,是业务逻辑层的容器
springmvc-config.xml —— SpringMVC容器,管理controller等对象,是视图层的容器
web.xml —— 配置SpringMVC前端控制器、过滤器等
👾项目结构

👾开发工具
编辑器:IDEA企业版
构建系统:Maven
数据库:MySQL 8.0.31
1️⃣导入依赖
使用maven构建工具开发,在pom.xml目录下导入相关依赖:
👾MyBatis与数据库相关依赖
🔴MySQL连接
<dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId><version>8.0.21</version></dependency>
🔴Druid数据库连接池
<dependency><groupId>com.alibaba</groupId><artifactId>druid</artifactId><version>1.1.23</version></dependency>
🔴MyBatis
<dependency><groupId>org.mybatis</groupId><artifactId>mybatis</artifactId><version>3.5.2</version></dependency>
👾Spring与SpringMVC相关依赖
🔴Spring与SpringMVC
<dependency><groupId>org.springframework</groupId><artifactId>spring-webmvc</artifactId><version>5.2.9.RELEASE</version></dependency>
🔴Spring对ORM支持的依赖
<dependency><groupId>org.springframework</groupId><artifactId>spring-orm</artifactId><version>5.2.9.RELEASE</version></dependency>
👾MyBatis和Spring关联依赖
<dependency><groupId>org.mybatis</groupId><artifactId>mybatis-spring</artifactId><version>2.0.2</version></dependency>
👾其他依赖
🔴Servlet依赖
<dependency><groupId>javax.servlet</groupId><artifactId>javax.servlet-api</artifactId><version>3.1.0</version></dependency>
🔴JSON依赖
<dependency><groupId>com.fasterxml.jackson.core</groupId><artifactId>jackson-databind</artifactId><version>2.11.4</version></dependency>
👾总览
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd"><modelVersion>4.0.0</modelVersion><groupId>org.example</groupId><artifactId>Demo</artifactId><packaging>war</packaging><version>1.0-SNAPSHOT</version><name>Demo Maven Webapp</name><url>http://maven.apache.org</url><dependencies><dependency><groupId>junit</groupId><artifactId>junit</artifactId><version>4.13.2</version><scope>test</scope></dependency><!--MyBatis依赖--><dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId><version>8.0.21</version></dependency><dependency><groupId>com.alibaba</groupId><artifactId>druid</artifactId><version>1.1.23</version></dependency><dependency><groupId>org.mybatis</groupId><artifactId>mybatis</artifactId><version>3.5.2</version></dependency><!--SpringMVC依赖--><dependency><groupId>org.springframework</groupId><artifactId>spring-webmvc</artifactId><version>5.2.9.RELEASE</version></dependency><!--Spring对ORM支持的依赖--><dependency><groupId>org.springframework</groupId><artifactId>spring-orm</artifactId><version>5.2.9.RELEASE</version></dependency><!--MyBatis和Spring关联的依赖--><dependency><groupId>org.mybatis</groupId><artifactId>mybatis-spring</artifactId><version>2.0.2</version></dependency><!--json的依赖--><dependency><groupId>com.fasterxml.jackson.core</groupId><artifactId>jackson-databind</artifactId><version>2.11.4</version></dependency></dependencies><build><finalName>Demo</finalName></build>
</project>
点击右上角的小按钮刷新导入

2️⃣编写配置文件
👾编写Spring-config.xml
🔴创建xml文件
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xmlns:context="http://www.springframework.org/schema/context" xmlns:tx="http://www.springframework.org/schema/tx"xsi:schemaLocation="http://www.springframework.org/schema/beanshttp://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context https://www.springframework.org/schema/context/spring-context.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd">
</beans>
🔴Dao层配置
<!--配置数据源--><bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource"><property name="driverClassName" value="com.mysql.jdbc.Driver"/><property name="url" value="jdbc:mysql://localhost:3306/db_study?serverTimezone=UTC"/><property name="username" value="root"/><property name="password" value="root"/></bean><!--配置SqlSessionFactoryBean--><bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean"><property name="dataSource" ref="dataSource"/></bean><!--配置MapperScannerConfigurer--><bean id="mapperScanner" class="org.mybatis.spring.mapper.MapperScannerConfigurer"><property name="sqlSessionFactory" ref="sqlSessionFactory"/><property name="basePackage" value="com.app.dao"/></bean>
🔴Service层配置
<!--扫描所有的注解的类--><context:component-scan base-package="com.app"><!--IoC容器排除@Controller注解的类--><context:exclude-filter type="annotation" expression="org.springframework.stereotype.Controller"/></context:component-scan><!--事务管理器--><bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager"><property name="dataSource" ref="dataSource"/></bean><!--声明式事务--><tx:annotation-driven/>
🔴总览
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xmlns:context="http://www.springframework.org/schema/context" xmlns:tx="http://www.springframework.org/schema/tx"xsi:schemaLocation="http://www.springframework.org/schema/beanshttp://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context https://www.springframework.org/schema/context/spring-context.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd"><!--Dao层--><!--配置数据源--><bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource"><property name="driverClassName" value="com.mysql.jdbc.Driver"/><property name="url" value="jdbc:mysql://localhost:3306/db_study?serverTimezone=UTC"/><property name="username" value="root"/><property name="password" value="root"/></bean><!--配置SqlSessionFactoryBean--><bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean"><property name="dataSource" ref="dataSource"/></bean><!--配置MapperScannerConfigurer--><bean id="mapperScanner" class="org.mybatis.spring.mapper.MapperScannerConfigurer"><property name="sqlSessionFactory" ref="sqlSessionFactory"/><property name="basePackage" value="com.app.dao"/></bean><!--Service层--><!--扫描所有的注解的类--><context:component-scan base-package="com.app"><!--IoC容器排除@Controller注解的类--><context:exclude-filter type="annotation" expression="org.springframework.stereotype.Controller"/></context:component-scan><!--事务管理器--><bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager"><property name="dataSource" ref="dataSource"/></bean><!--声明式事务--><tx:annotation-driven transaction-manager="transactionManager"/>
</beans>
👾编写Springmvc-config.xml
🔴创建xml文件
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xmlns:context="http://www.springframework.org/schema/context"xmlns:mvc="http://www.springframework.org/schema/mvc"xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context https://www.springframework.org/schema/context/spring-context.xsd http://www.springframework.org/schema/mvc https://www.springframework.org/schema/mvc/spring-mvc.xsd">
</beans>
🔴Controller层
<!--扫描所有的Controller--><context:component-scan base-package="com.app.controller"/><!--配置映射器和适配器bean,同时增加其他功能--><mvc:annotation-driven/><!--交给web服务器处理,处理所有静态资源--><mvc:default-servlet-handler/><!--视图解析器--><bean class="org.springframework.web.servlet.view.InternalResourceViewResolver"><property name="prefix" value="/"/><property name="suffix" value=".jsp"/></bean>
🔴总览
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xmlns:context="http://www.springframework.org/schema/context"xmlns:mvc="http://www.springframework.org/schema/mvc"xsi:schemaLocation="http://www.springframework.org/schema/beanshttp://www.springframework.org/schema/beans/spring-beans.xsdhttp://www.springframework.org/schema/contexthttps://www.springframework.org/schema/context/spring-context.xsdhttp://www.springframework.org/schema/mvchttps://www.springframework.org/schema/mvc/spring-mvc.xsd"><!--扫描所有的Controller--><context:component-scan base-package="com.app.controller"/><!--配置映射器和适配器bean,同时增加其他功能--><mvc:annotation-driven/><!--交给web服务器处理,处理所有静态资源--><mvc:default-servlet-handler/><!--视图解析器--><bean class="org.springframework.web.servlet.view.InternalResourceViewResolver"><property name="prefix" value="/"/><property name="suffix" value=".jsp"/></bean>
</beans>
👾编写web.xml
🔴Spring监听器
<context-param><param-name>contextConfigLocation</param-name><param-value>classpath:spring-config.xml</param-value></context-param>
<listener><listener-class>org.springframework.web.context.ContextLoaderListener</listener-class></listener>
🔴编码过滤器
<!--编码过滤器--><filter><filter-name>characterEncodingFilter</filter-name><filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class><init-param><param-name>encoding</param-name><param-value>UTF-8</param-value></init-param></filter><filter-mapping><filter-name>characterEncodingFilter</filter-name><url-pattern>/*</url-pattern></filter-mapping>
🔴隐藏域过滤器
<filter><filter-name>hiddenHttpMethodFilter</filter-name><filter-class>org.springframework.web.filter.HiddenHttpMethodFilter</filter-class></filter><filter-mapping><filter-name>hiddenHttpMethodFilter</filter-name><url-pattern>/*</url-pattern></filter-mapping>
🔴前端控制器
<servlet><servlet-name>dispatcherServlet</servlet-name><servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class><init-param><param-name>contextConfigLocation</param-name><param-value>classpath:springmvc-config.xml</param-value></init-param></servlet><servlet-mapping><servlet-name>dispatcherServlet</servlet-name><url-pattern>/</url-pattern></servlet-mapping>
🔴总览
<!DOCTYPE web-app PUBLIC"-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN""http://java.sun.com/dtd/web-app_2_3.dtd" ><web-app><display-name>Archetype Created Web Application</display-name><!--spring-config.xml配置文件位置--><context-param><param-name>contextConfigLocation</param-name><param-value>classpath:spring-config.xml</param-value></context-param><!--编码过滤器--><filter><filter-name>characterEncodingFilter</filter-name><filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class><init-param><param-name>encoding</param-name><param-value>UTF-8</param-value></init-param></filter><!--隐藏域过滤器--><filter><filter-name>hiddenHttpMethodFilter</filter-name><filter-class>org.springframework.web.filter.HiddenHttpMethodFilter</filter-class></filter><filter-mapping><filter-name>hiddenHttpMethodFilter</filter-name><url-pattern>/*</url-pattern></filter-mapping><filter-mapping><filter-name>characterEncodingFilter</filter-name><url-pattern>/*</url-pattern></filter-mapping><!--上下文加载程序监听器--><listener><listener-class>org.springframework.web.context.ContextLoaderListener</listener-class></listener><!--前端控制器--><servlet><servlet-name>dispatcherServlet</servlet-name><servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class><init-param><param-name>contextConfigLocation</param-name><param-value>classpath:springmvc-config.xml</param-value></init-param></servlet><servlet-mapping><servlet-name>dispatcherServlet</servlet-name><url-pattern>/</url-pattern></servlet-mapping>
</web-app>
3️⃣MySQL数据库配置
👾登录MySQL
管理员身份启动cmd,输入 net start mysql 启动 mysql 数据库服务。
net start mysql

输入用户名、密码登录 mysql
mysql -u 你的用户名 -p

查看 mysql 中的数据库,选择你的数据库
show databases;
use 你的数据库;

👾创建 user 表
创建了一张 user 表,包含了 id,name,password 三个字段。其中 id 字段为主键,设置为自动增长。
create table user(id int primary key auto_increment,name varchar(20),password varchar(20));

👾插入数据
插入若干条记录,用于后面的测试
insert into user values(null,"ketty","root");
查看表
select * from user;

4️⃣IDEA连接数据库
👾选择MySQL
打开IDEA右侧的数据库连接,选择 + 号,选择MySQL.

👾填写相关配置
填写相关配置,包括MySQL连接的用户名和密码,要连接的数据库,在URL的后面添加如下字段:
?serverTimezone=GMT&useSSL=false

连接成功后,可以看见我们数据库中的表。如果没有出现表,可以点击上面的刷新按钮刷新一下

5️⃣数据访问层(dao、pojo)编写
数据访问层需要编写dao类、pojo类、dao.xml文件。我们使用IDEA插件自动生成。
👾添加插件
找到插件,在搜索栏搜索better-mybatis-generator插件,点击添加。


👾新建目录存放类
右键src/main/java目录,新建com.app.pojo、com.app.dao、com.app.service目录

👾填写要生成类的相关信息
右键user类,选择mabatis-generate选项。

这里我们修改pojo类、dao类、dao.xml 三大类文件生成的位置(红框标注处),分别修改成我们刚刚新建的com.app.pojo包以及com.app.dao包。

❗注意如果你的mysql版本是8.0及以上,需要勾选下面mysql_8(红框标注处)
❗查看mysql版本:打开cmd,输入mysql -V
mysql -V

修改完毕后,点击确定。第一次连接会要我们输入数据库连接的账号和密码。填写后在点击确定。
可以看见,我们的com.app.pojo和com.app.dao目录下多了四个文件。这四个文件是插件自动帮我们生成的,包括生成了一些常用的SQL单表操作,如根据条件查询,根据条件修改等。我们在service中就可以直接使用他们了。


6️⃣业务逻辑层(service)编写
👾UserService接口
package com.app.service;import com.app.pojo.User;public interface UserService {User findUserByNameAndPassword(User user);
}
👾UserServiceImpl实现类
package com.app.service.impl;import com.app.dao.UserDao;
import com.app.pojo.User;
import com.app.pojo.UserExample;
import com.app.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;import java.util.List;@Service
@Transactional
public class UserServiceImpl implements UserService {@Autowired // Spring自动注入private UserDao userDao;public User findUserByNameAndPassword(User user) {UserExample userExample = new UserExample();UserExample.Criteria criteria = userExample.createCriteria();criteria.andNameEqualTo(user.getName());criteria.andPasswordEqualTo(user.getPassword());List<User> userList = userDao.selectByExample(userExample);return userList.size() > 0 ? userList.get(0) : null;}
}
7️⃣表示层(controller、view)编写
👾UserController类(示例:用户登录)
package com.app.controller;import com.app.pojo.User;
import com.app.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;@Controller
@RequestMapping("user")
public class UserController {@Autowiredprivate UserService userService;@GetMapping// 使用RESTful风格编写public String login(User user) {User loginUser = userService.findUserByNameAndPassword(user);if (loginUser != null) return "welcome";else return "redirect:login.jsp";}
}
👾login.jsp(用户登录界面)
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head><title>login</title>
</head>
<body>
<form action="user" method="get">name:<input name="name"><br>password:<input name="password"><br><input type="submit">
</form>
</body>
</html>
👾welcome.jsp(登录成功界面)
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head><title>welcome</title>
</head>
<body>
<h1>Welcome!!</h1>
</body>
</html>
8️⃣验证
打开浏览器,输入 http://localhost:8080/Demo_war/login.jsp

👾登录成功
输入存在的用户,转到welcom.jsp页面

👾登录失败
输入不存在的用户信息,重定向回login.jsp页面
