SSM框架整合总结—案例

??前言：

之前我们已经把Mybatis、Spring、SpringMVC介绍完毕，忘记的同学可以查看博客主页??秀琴的秘密花园。这篇文章严格采用SSM框架把Mybatis、Spring、SpringMVC整合在一起。??祝大家学有所成。

**??**成大事不在于力量的大小,而在于能坚持多久。——塞·约翰生

目录

环境

???Mybatis层

???Spring层

???SpringMVC层

---

??环境

• IDEA

• MySQL 5.7.19

• Tomcat 9

• Maven 3.6

• Spring

基本环境搭建（添加依赖）—pom.xml

<dependencies>
   <!--Junit-->
   <dependency>
       <groupId>junit</groupId>
       <artifactId>junit</artifactId>
       <version>4.12</version>
   </dependency>
   <!--数据库驱动-->
   <dependency>
       <groupId>mysql</groupId>
       <artifactId>mysql-connector-java</artifactId>
       <version>5.1.47</version>
   </dependency>
   <!-- 数据库连接池 -->
   <dependency>
       <groupId>com.mchange</groupId>
       <artifactId>c3p0</artifactId>
       <version>0.9.5.2</version>
   </dependency>

   <!--Servlet - JSP -->
   <dependency>
       <groupId>javax.servlet</groupId>
       <artifactId>servlet-api</artifactId>
       <version>2.5</version>
   </dependency>
   <dependency>
       <groupId>javax.servlet.jsp</groupId>
       <artifactId>jsp-api</artifactId>
       <version>2.2</version>
   </dependency>
   <dependency>
       <groupId>javax.servlet</groupId>
       <artifactId>jstl</artifactId>
       <version>1.2</version>
   </dependency>

   <!--Mybatis-->
   <dependency>
       <groupId>org.mybatis</groupId>
       <artifactId>mybatis</artifactId>
       <version>3.5.2</version>
   </dependency>
   <dependency>
       <groupId>org.mybatis</groupId>
       <artifactId>mybatis-spring</artifactId>
       <version>2.0.2</version>
   </dependency>

   <!--Spring-->
   <dependency>
       <groupId>org.springframework</groupId>
       <artifactId>spring-webmvc</artifactId>
       <version>5.1.9.RELEASE</version>
   </dependency>
   <dependency>
       <groupId>org.springframework</groupId>
       <artifactId>spring-jdbc</artifactId>
       <version>5.1.9.RELEASE</version>
   </dependency>
</dependencies>

建立基本结构和配置框架

??Mybatis层

1、数据库配置文件 database.properties

jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/test
jdbc.username=root
jdbc.password=123

2、编写MyBatis的核心配置文件

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration >


<!--通过properties标签加载外部properties文件-->

    <properties resource="jdbc.properties"></properties>
<!--自定义别名-->
<typeAliases>
    <typeAlias type="com.itheima.domain.User" alias="user"></typeAlias>
    <typeAlias type="com.itheima.domain.Role" alias="role"></typeAlias>

</typeAliases>

<!--加载映射关系-->
    <mappers>
        <package name="com.itheima.dao"></package>
    </mappers>
</configuration>

3.编写Dao层的 Mapper接口（注解形式）

    //查一个
    @Select("select * from  sys_user_role ur,sys_role r where ur.roleId=r.id and ur.userId=#{id}")
    public List<Role> findById(Long id);

    //查所有
    @Select("select * from sys_role")
    public List<Role> findAll();

    //增
    @Insert("insert into sys_role values(#{id}, #{roleName},#{roleDesc})")
    public void save(Role role);

    //删
    @Delete("delete from sys_role where id=#{id}")
    public void delete(int id);

4.编写Service层的接口和实现类

5.实现类

??Spring层

1、配置Spring整合MyBatis，我们这里数据源使用c3p0连接池；

2、我们去编写Spring整合Mybatis的相关的配置文件；spring-dao.xml

<?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"
       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">

    <!-- 配置整合mybatis -->
    <!-- 1.关联数据库文件 -->
    <context:property-placeholder location="classpath:jdbc.properties"/>

    <!-- 2.数据库连接池 -->
    <!--数据库连接池
        dbcp 半自动化操作 不能自动连接
        c3p0 自动化操作（自动的加载配置文件 并且设置到对象里面）
    -->
    <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
        <!-- 配置连接池属性 -->
        <property name="driverClass" value="${jdbc.driver}"/>
        <property name="jdbcUrl" value="${jdbc.url}"/>
        <property name="user" value="${jdbc.username}"/>
        <property name="password" value="${jdbc.password}"/>

        <!-- c3p0连接池的私有属性 -->
        <property name="maxPoolSize" value="30"/>
        <property name="minPoolSize" value="10"/>
        <!-- 关闭连接后不自动commit -->
        <property name="autoCommitOnClose" value="false"/>
        <!-- 获取连接超时时间 -->
        <property name="checkoutTimeout" value="10000"/>
        <!-- 当获取连接失败重试次数 -->
        <property name="acquireRetryAttempts" value="2"/>
    </bean>

    <!-- 3.配置SqlSessionFactory对象 -->
    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <!-- 注入数据库连接池 -->
        <property name="dataSource" ref="dataSource"/>
        <!-- 配置MyBaties全局配置文件:mybatis-config.xml -->
        <property name="configLocation" value="classpath:sqlMapConfig.xml"/>
    </bean>

    <!-- 4.配置扫描Dao接口包，动态实现Dao接口注入到spring容器中 -->
    <!--解释 ：https://www.cnblogs.com/jpfss/p/7799806.html-->
    <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
        <!-- 注入sqlSessionFactory -->
        <property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"/>
        <!-- 给出需要扫描Dao接口包 -->
        <property name="basePackage" value="com.itheima.dao"/>
    </bean>



</beans>

3、Spring整合service层

<?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"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
   http://www.springframework.org/schema/beans/spring-beans.xsd
   http://www.springframework.org/schema/context
   http://www.springframework.org/schema/context/spring-context.xsd">

    <!-- 扫描service相关的bean -->
    <context:component-scan base-package="com.itheima.service" />

    <!-- 配置事务管理器 -->
    <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
        <!-- 注入数据库连接池 -->
        <property name="dataSource" ref="dataSource" />
    </bean>

</beans>

**??**SpringMVC层

1、web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
         version="4.0">

  <!--解决乱码的过滤器-->
  <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>

  <!--全局的初始化参数-->
  <context-param>
    <param-name>contextConfigLocation</param-name>
    <param-value>classpath:applicationContext.xml</param-value>
  </context-param>
  <!--Spring的监听器-->
  <listener>
    <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
  </listener>


  <!--SpringMVC的前端控制器-->
  <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:spring-mvc.xml</param-value>
    </init-param>
    <load-on-startup>2</load-on-startup>
  </servlet>
  <servlet-mapping>
    <servlet-name>DispatcherServlet</servlet-name>
    <url-pattern>/</url-pattern>
  </servlet-mapping>

</web-app>

2、spring-mvc.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:mvc="http://www.springframework.org/schema/mvc"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd
        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">


    <!--1.MVC注解驱动-->
    <mvc:annotation-driven/>

    <!--2.配置视图解析器-->
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="prefix" value="/pages/"/>
        <property name="suffix" value=".jsp"/>
    </bean>

    <!--3.静态资源权限开放-->
    <mvc:default-servlet-handler/>

    <!--4.组件扫描Controller-->
    <context:component-scan base-package="com.itheima.controller"/>

</beans>

3、Spring配置整合文件，applicationContext.xml

??重点

1.配置Mybatis时，需导入特殊依赖，否则无法导入

2.当出现——Parameter ‘xxx‘ not found. Available parameters are [xxx,xxx, param3, param1,param2]错误时。

解决过程如下：
1.对于mapper接口中，传入的参数有多个时必须使用@param进行标识.

2.当需要返回已经增加的主键id时