SpringMVC入门二：SSM整合（spring+springmvc+mybatis）

一、编程步骤

1、引入依赖

spring、springmvc、mybatis、mybatis-spring、mysql、druid、log4j、servlet-api、jstl、fastjson

2、SM整合=Spring+mybatis

1）建表

2）实体类

3）DAO接口

public interface UserDao {
    List<User>findAll();
    void save(User user);
}

4）Mapper配置文件（位置：resources/mapper/UserDaoMapper.xml）

<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">

<mapper namespace="com.icucoder.dao.UserDao">
    <select id="findAll" resultType="User">
        select id, name, age, email
        from user;
    </select>
    <insert id="save" parameterType="User">
        insert into user
        values (#{id}, #{name}, #{age}, #{email});
    </insert>

</mapper>

5）Service接口

public interface UserService {
    List<User> findAll();

    void save(User user);
}

6）Service实现类 @Service @Transactional 注入DAO对象

@Service("userService")
@Transactional
public class UserServiceImpl implements UserService {
    @Autowired
    UserDao userDao;

    public List<User> findAll() {
        return userDao.findAll();
    }

    public void save(User user) {
        userDao.save(user);
        //int i = 1 / 0;
        System.out.println("save success");
    }
}

7）引入spring.xml文件，编写spring整合mybatis配置

（1）开启注解扫描<context:component-scan base-package="com.icucoder"/>

<context:component-scan base-package="com.icucoder"/>

（2）创建数据源对象DruidDataSource ，注入driverClassName url username passwrod

<bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource">
        <property name="driverClassName" value="com.mysql.cj.jdbc.Driver"/>
        <property name="url" value="jdbc:mysql://127.0.0.1:3306/springboot?characterEncoding=UTF-8&serverTimezone=UTC"/>
        <property name="username" value="root"/>
        <property name="password" value="xroot"/>
    </bean>

（3）创建SqlSessionFactoryBean对象SqlSessionFactory ，注入dataSource，注入mapper配置文件位置mapperLocations，注入typeAliasesPackage

<bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <property name="dataSource" ref="dataSource"/>
        <property name="mapperLocations" value="classpath:mapper/*.xml"/>
        <property name="typeAliasesPackage" value="com.icucoder.entity"/>
    </bean>

（4）创建DAO，使用MapperScannerConfigurer配置某路径下DAO自动扫描，注入sqlSessionFactoryBeanName配置sqlSessionFactory和注入basePackage配置DAO接口所在包

<bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
        <property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"/>
        <!--扫描DAO接口所在包-->
        <property name="basePackage" value="com.icucoder.dao"/>
    </bean>

（5）创建事务管理器DataSourceTransactionManager，注入DataSource

<bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
        <property name="dataSource" ref="dataSource"/>
    </bean>

（6）开启注解式事务驱动<tx:annotation-driven transaction-manager="事务管理器在工厂中的唯一标识"/>

<tx:annotation-driven transaction-manager="transactionManager"/>

8）测试Service方法调用

ApplicationContext context = new ClassPathXmlApplicationContext("spring.xml");
UserService userService = (UserService) context.getBean("userService");
User user=new User(7,"test",12,"admin@qq.com");
userService.save(user);
System.out.println(userService.findAll());

3、SS整合=Spring+SpringMVC

1）配置web.xml

（1）启动工厂监听器

<listener>
    <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>

（2）配置工厂配置文件spring.xml

<context-param>
    <param-name>contextConfigLocation</param-name>
    <param-value>classpath:spring.xml</param-value>
</context-param>

（3）配置springmvc核心的Servlet：DispatcherServlet，url-pattern /，并在init-param中配置contextConfigLocation为classpath:springmvc.xml

<servlet>
    <servlet-name>springmvc</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    <init-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>classpath:springmvc.xml</param-value>
    </init-param>
</servlet>

<servlet-mapping>
    <servlet-name>springmvc</servlet-name>
    <url-pattern>/</url-pattern>
</servlet-mapping>

（4）配置springmvc接收post请求中文乱码 CharacterEncodingFilter usl-pattern /* init-param encoding UTF-8

<filter>
    <filter-name>charset</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>charset</filter-name>
    <url-pattern>/*</url-pattern>
</filter-mapping>

2）引入springmvc.xml

（1）开启注解扫描controller

<context:component-scan base-package="com.icucoder.controller"/>

（2）配置处理器映射器和处理器适配器

<mvc:annotation-driven/>

（3）配置视图解析器

<bean id="internalResourceViewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
    <property name="prefix" value="/"/>
    <property name="suffix" value=".jsp"/>
</bean>

3）开发Controller并使用@Controller和@RequestMapping，注入Service

（1）controller

@Controller
@RequestMapping("/user")
public class UserController {

    @Autowired
    private UserService userService;

    @RequestMapping("/all")
    public String getUser(HttpServletRequest request) {
        List<User> users = userService.findAll();
        request.setAttribute("users", users);
        return "index";
    }
}

（2）jsp

<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
<h3>all users info</h3>
<c:forEach items="${requestScope.users}" var="user">
    ${user.id} & ${user.name}
</c:forEach>
</body>
</html>

4）服务器附属并访问测试

http://localhost:8080/spring_sprinmvc_mybatis_war/user/all

二、说明

1、现有SSM开发存在的问题

1）大量maven冗余配置

2）每次构建项目都要书写大量相同配置极大浪费了项目开发时间

3）每次整合第三方技术都要编写相关配置文件

4）项目测试每次都需要部署到tomcat