Mybatis(SSM整合)

1.SSM整合

（1）创建web的maven工程

（2）引入相关依赖

<dependencies>
        <!--加入springwebmvc-->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-webmvc</artifactId>
      <version>5.2.9.RELEASE</version>
    </dependency>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-aspects</artifactId>
      <version>5.2.9.RELEASE</version>
    </dependency>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-jdbc</artifactId>
      <version>5.2.9.RELEASE</version>
    </dependency>

    <dependency>
      <groupId>com.fasterxml.jackson.core</groupId>
      <artifactId>jackson-core</artifactId>
      <version>2.11.4</version>
    </dependency>
    <dependency>
      <groupId>com.fasterxml.jackson.core</groupId>
      <artifactId>jackson-annotations</artifactId>
      <version>2.11.4</version>
    </dependency>
    <dependency>
      <groupId>com.fasterxml.jackson.core</groupId>
      <artifactId>jackson-databind</artifactId>
      <version>2.11.4</version>
    </dependency>
      <!--加入mybatis的依赖-->
    <dependency>
      <groupId>org.mybatis</groupId>
      <artifactId>mybatis</artifactId>
      <version>3.5.6</version>
    </dependency>
     <!--spring和mybatis整合的依赖-->
    <dependency>
      <groupId>org.mybatis</groupId>
      <artifactId>mybatis-spring</artifactId>
      <version>2.0.6</version>
    </dependency>
     <!--mysql的驱动-->
    <dependency>
      <groupId>mysql</groupId>
      <artifactId>mysql-connector-java</artifactId>
      <version>5.1.49</version>
    </dependency>
    <!--数据库连接池druid-->
    <dependency>
      <groupId>com.alibaba</groupId>
      <artifactId>druid</artifactId>
      <version>1.1.21</version>
    </dependency>

    <!--generator-->
    <dependency>
      <groupId>org.mybatis.generator</groupId>
      <artifactId>mybatis-generator-core</artifactId>
      <version>1.4.0</version>
    </dependency>
  </dependencies>

根据需要再添加其它依赖。

(3) 加入相关的配置文件 springmvc，spring。

① springmvc的配置文件

<?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">

    <!--包的扫描-->
    <context:component-scan base-package="com.aaa.controller"/>

    <!--静态资源的放行-->
    <mvc:default-servlet-handler/>

    <!--开启驱动注解-->
    <mvc:annotation-driven/>

    <!--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>
</beans>

② spring的配置文件

<?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"
       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">
      <!--扫描service包-->
      <context:component-scan base-package="com.aaa.service"/>
       <!--配置数据源-->
      <bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource">
           <property name="username" value="root"/>
           <property name="password" value="654123"/>
           <property name="driverClassName" value="com.mysql.jdbc.Driver"/>
           <property name="url" value="jdbc:mysql://localhost:3306/user"/>
      </bean>
      <!--SqlSessionFactory-->
      <bean class="org.mybatis.spring.SqlSessionFactoryBean">
           <property name="dataSource" ref="dataSource"/>
           <!--加载mybatis的映射文件-->
            <property name="mapperLocations" value="classpath:mapper/*.xml"/>
      </bean>

      <!--为dao接口生成实现类对象-->
      <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
            <property name="basePackage" value="com.aaa.dao"/>
      </bean>

</beans>

③ 配置web.xml文件

<?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">
  <display-name>Archetype Created Web Application</display-name>
  <!--DispatcherServlet-->
  <servlet>
    <servlet-name>springmvc</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    <!--指定加载的配置文件-->
    <init-param>
      <param-name>contextConfigLocation</param-name>
      <param-value>classpath:springmvc.xml</param-value>
    </init-param>
    <!--启动tomcat时加载该配置文件-->
    <load-on-startup>1</load-on-startup>
  </servlet>
  
  <servlet-mapping>
    <servlet-name>springmvc</servlet-name>
    <url-pattern>/</url-pattern>
  </servlet-mapping>
  
  <!--监听器-->
  <context-param>
    <param-name>contextConfigLocation</param-name>
    <param-value>classpath:applicationContext.xml</param-value>
  </context-param>
  <listener>
    <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
  </listener>
   
</web-app>

(4) Dao、Entity、Mapper通过代码生成器完成---

① 创建并配置generator.xml文件

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE generatorConfiguration
        PUBLIC "-//mybatis.org//DTD MyBatis Generator Configuration 1.0//EN"
        "http://mybatis.org/dtd/mybatis-generator-config_1_0.dtd">
<generatorConfiguration>
    <!--mysql驱动jar所在的绝对路径 必须低于8.0以下  -->
    <classPathEntry location="D:\JAVA\maven-repository\mysql\mysql-connector-java\5.1.26\mysql-connector-java-5.1.26.jar" />
    <context id="DB2Tables" targetRuntime="MyBatis3">
        <!--        去除英文注释-->
        <commentGenerator>
            <property name="suppressAllComments" value="true" />
        </commentGenerator>
        <!--连接数据库的信息-->
        <jdbcConnection driverClass="com.mysql.jdbc.Driver"
                        connectionURL="jdbc:mysql:///school_db"
                        userId="root"
                        password="123@qwe">
        </jdbcConnection>
        <javaTypeResolver >
            <property name="forceBigDecimals" value="false" />
        </javaTypeResolver>

        <!--实体类生成的路径-->
        <javaModelGenerator targetPackage="com.aaa.entity" targetProject="./src/main/java">
            <property name="enableSubPackages" value="true" />
            <property name="trimStrings" value="true" />
        </javaModelGenerator>

        <!--映射文件生成的路径-->
        <sqlMapGenerator targetPackage="mapper"  targetProject="./src/main/resources">
            <property name="enableSubPackages" value="true" />
        </sqlMapGenerator>

        <!--dao生成的路径
        targetPackage：包的名称
        targetProject：路径
        -->
        <javaClientGenerator type="XMLMAPPER" targetPackage="com.aaa.dao"  targetProject="./src/main/java">
            <property name="enableSubPackages" value="true" />
        </javaClientGenerator>

        <!--数据库的表信息
        schema：数据库名
        tableName：表名
        -->
        <table schema="school_db" tableName="t_class" domainObjectName="Tclass"
               enableUpdateByExample="false" enableSelectByExample="false" enableDeleteByExample="false"
               enableCountByExample="false">
        </table>
        <!--数据库的表信息-->
        <table schema="school_db" tableName="teacher" domainObjectName="Teacher"
               enableUpdateByExample="false" enableSelectByExample="false" enableDeleteByExample="false"
               enableCountByExample="false">
        </table>
    </context>
</generatorConfiguration>

② 运行 代码生成器

public class test01 {
    public static void main(String[] args)throws Exception {
        List<String> warnings = new ArrayList<String>();
        boolean overwrite = true;
        File configFile = new File("generator.xml");
        ConfigurationParser cp = new ConfigurationParser(warnings);
        Configuration config = cp.parseConfiguration(configFile);
        DefaultShellCallback callback = new DefaultShellCallback(overwrite);
        MyBatisGenerator myBatisGenerator = new MyBatisGenerator(config, callback, warnings);
        myBatisGenerator.generate(null);
    }
}

③ 创建service层

TeacherService接口类

Teacher selectByPrimaryKey(Integer tId);

TeacherServiceImpl接口实现类

@Service
public class TeacherServiceImpl implements TeacherService {

@Autowired
    private TeacherMapper teacherMapper;

 @Override
    public Teacher selectByPrimaryKey(Integer tId) {
        return teacherMapper.selectByPrimaryKey(tId);
    }
}

④ 创建TeacherController层

@RestController
public class TeacherController {

    @Autowired
    private TeacherService teacherService;

    @RequestMapping("/selectByPrimaryKey")
    public Teacher selectByPrimaryKey(Integer tId){
        Teacher teacher = teacherService.selectByPrimaryKey(tId);
        return teacher;
    }
}