SSM整合

• 正常创建一个maven项目，环境是jDK1.8及以上，maven3.8及以上
• 无论SSM项目、SpringBoot项目还是SpringCloud项目第一件事就是添加相关的依赖。这里是针对SSM整合导入相关的依赖

<?xml version="1.0" encoding="UTF-8"?>
<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/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.xsha.ssm</groupId>
    <artifactId>java-ssm</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>war</packaging>

    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
        <!-- 对spring版本进行统一管理 -->
        <spring.version>5.2.6.RELEASE</spring.version>
        <!-- 对spring security版本进行统一管理 -->
        <spring.security.version>4.2.10.RELEASE</spring.security.version>
    </properties>

    <dependencies>
        <!-- Spring 依赖 -->
        <!-- https://mvnrepository.com/artifact/org.springframework/spring-jdbc -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-jdbc</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.springframework/spring-webmvc -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-test</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.aspectj/aspectjweaver -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-aspects</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <!-- 数据库依赖 -->
        <!-- MySQL 驱动 -->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.46</version>
        </dependency>
        <!-- 数据源 -->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.2.8</version>
        </dependency>
        <!-- MyBatis -->
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.5.9</version>
        </dependency>
        <!-- MyBatis 与 Spring 整合 -->
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis-spring</artifactId>
            <version>2.0.5</version>
        </dependency>
        <!-- MyBatis 分页插件 -->
        <dependency>
            <groupId>com.github.pagehelper</groupId>
            <artifactId>pagehelper</artifactId>
            <version>5.3.0</version>
        </dependency>
        <!-- 日志 -->
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-api</artifactId>
            <version>1.7.7</version>
        </dependency>
        <dependency>
            <groupId>ch.qos.logback</groupId>
            <artifactId>logback-classic</artifactId>
            <version>1.2.3</version>
        </dependency>
        <!-- JSTL 标签库 -->
        <dependency>
            <groupId>jstl</groupId>
            <artifactId>jstl</artifactId>
            <version>1.2</version>
        </dependency>
        <!-- junit 测试 -->
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.13.2</version>
            <scope>test</scope>
        </dependency>
        <!-- 引入 Servlet 容器中相关依赖 -->
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>servlet-api</artifactId>
            <version>2.5</version>
            <scope>provided</scope>
        </dependency>
    </dependencies>
</project>

• 刚创建的maven项目是没有web.xml文件的（如果有就更好，是在webapp/WEB-INF目录下哦），如果没有，就要按照如下步骤添加
  • 点击File->Project Structure->Facets
    

• web.xml配置的内容基本上就是Servlet程序的三大组件：Listener监听器、DispatcherServlet程序（控制器）、Filter过滤器。

<?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">
    <!-- 指定要加载的Spring配置文件 -->
    <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>classpath:applicationContext.xml</param-value>
    </context-param>
    <!-- 监听器 -->
    <listener>
        <listener-class>org.springframework.web.context.ContextLoader</listener-class>
    </listener>
    <!-- 配置前端控制器 -->
    <servlet>
        <servlet-name>dispatcherServlet</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <load-on-startup>1</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>dispatcherServlet</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>
    <!-- 配置字符编码过滤器 -->
    <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>
        <init-param>
            <param-name>forceResponseEncoding</param-name>
            <param-value>true</param-value>
        </init-param>
        <init-param>
            <param-name>forceRequestEncoding</param-name>
            <param-value>true</param-value>
        </init-param>
    </filter>
    <filter-mapping>
        <filter-name>characterEncodingFilter</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>
    <!-- 配置允许前端delete、put、patch等请求的过滤器 -->
    <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>
</web-app>

• 写到这里你肯定会发现有一个地方会报红，那就是缺少了Spring配置文件applicationContext.xml，其实applicationContext.xml配置文件
  就是Spring配置文件的一部分，因为Spring要与Mybatis整合，Spring配置文件一分为二，一部分是Spring与Mybatis整合的配置文件applicationContext.xml，一部分是
  Spring与SpringMvc的配置文件dispatcherServlet.xml。
  • applicationContext.xml
  • 另外还需要在类路径下创建一个mapper的目录

<?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:aop="http://www.springframework.org/schema/aop"
       xmlns:tx="http://www.springframework.org/schema/tx"
       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
                           http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd
                           http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd
">
  <!-- 除了控制器的扫描，当前包下的都会扫描 -->
  <context:component-scan base-package="com.xsha.ssm">
    <context:exclude-filter type="annotation" expression="org.springframework.stereotype.Controller"/>
  </context:component-scan>

  <!-- 引入外部配置文件 -->
  <context:property-placeholder location="classpath:jdbc.properties" />

  <!-- Spring配置文件，这里主要配置和业务逻辑相关的 -->
  <!-- 数据源和事务控制 -->
  <bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource">
    <property name="driverClassName" value="${jdbc.driverClassName}" />
    <property name="url" value="${jdbc.url}" />
    <property name="username" value="${jdbc.username}" />
    <property name="password" value="${jdbc.password}" />
  </bean>

  <!-- 配置Spring与Mybatis的整合 -->
  <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
    <!-- 指定Mybatis全局配置文件 -->
    <property name="configLocation" value="classpath:mybatisConfig.xml" />
    <property name="dataSource" ref="dataSource" />
    <!-- 指定Mybatis的mapper.xml文件的位置 -->
    <property name="mapperLocations" value="classpath:mapper/*.xml"  />
  </bean>

  <!-- 配置扫描器，将Mybatis接口的实现加入到IOC容器中 -->
  <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
    <!-- 扫描所有dao（或者mapper）接口的实现类 -->
    <property name="basePackage" value="com.xsha.ssm.mapper" />
  </bean>

  <!-- 事务控制 -->
  <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
    <!-- 控制数据源 -->
    <property name="dataSource" ref="dataSource" />
  </bean>
  <!-- 开启基于注解的事务，使用xml配置形式的事务 -->
  <aop:config>
    <aop:pointcut id="txPoint" expression="execution(* com.xsha.ssm.service.. *(..))"/>
    <!-- 配置事务增强 -->
    <aop:advisor advice-ref="txAdvice" pointcut-ref="txPoint" />
  </aop:config>
  <!-- 配置事务增强，事务如何切入 -->
  <tx:advice id="txAdvice">
    <tx:attributes>
      <!-- 所有方法都是事务方法 -->
      <tx:method name="*" />
      <!-- 以get开头的方法 -->
      <tx:method name="get*" read-only="true" />
    </tx:attributes>
  </tx:advice>
</beans>

• 这个配置配置文件的作用主要是Mybatis的全局配置，如实体类类型的别名、驼峰式命名
  • mybatisConfig.xml

<?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>
  <settings>
    <setting name="mapUnderscoreToCamelCase" value="true"/>
  </settings>
  <!-- 设置类型别名 -->
  <typeAliases>
    <package name="com.xsha.ssm.entity"/>
  </typeAliases>
</configuration>

• 同样，上面还是缺少了一个配置文件，就是连接数据库的配置文件jdbc.properties

jdbc.driverClassName=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql:///database_name?useUnicode=true&characterEncoding=utf8
jdbc.username=username
jdbc.password=password

• 到这里，就已经实现了Spring和Mybatis的整合。接下来就是实现Spring和SpringMvc的整合，在上面的web.xml就基本配置完成Spring和SpringMvc的整合，
  就差一个视图解析器的配置文件dispatcherServlet.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"
       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 http://www.springframework.org/schema/context/spring-context.xsd
                           http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd
">
  <!-- SpringMvc的配置文件，包括网站跳转逻辑控制 -->
  <context:component-scan base-package="com.xsha.ssm" use-default-filters="false">
    <!-- 只能扫描控制器 -->
    <context:include-filter type="annotation" expression="org.springframework.stereotype.Controller" />
  </context:component-scan>
  
  <!-- 配置视图解析器 -->
  <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
    <property name="prefix" value="/WEB-INF/views" />
    <property name="suffix" value=".jsp" />
  </bean>
  
  <!-- 两个标准配置 -->
  <!-- 将SpringMvc不能处理的交割tomcat处理 -->
  <mvc:default-servlet-handler />
  <mvc:annotation-driven />
</beans>

• SSM的整合已经实现，大家可通过单元测试