SpringBoot之整合MyBatis

　　今天了解一下SpringBoot如何与我们最常用的ORM框架Mybatis整合。

一、

　　需要在pom.xml文件里加入mybatis的依赖

<dependency>
    <groupId>org.mybatis.spring.boot</groupId>
    <artifactId>mybatis-spring-boot-starter</artifactId>
    <version>1.3.2</version>
</dependency>

二、

　　需要在application.properties文件里加关于mybatis的配置

#mybatis配置
mybatis.mapper-locations=classpath:mapper/*.xml      ------意思是mapper文件在classpath下的mapper里
mybatis.type-aliases-package=com.renruibin.springbootmybatis.pojo    -------设置自定义的Pojo别名为首写字母小写的pojo

#数据源配置
spring.datasource.url=jdbc:mysql://localhost:3306/springbootmybatis
spring.datasource.driver-class-name=com.mysql.jdbc.Driver
spring.datasource.username=root
spring.datasource.password=rrb

三、

　　使用Ant，达到自动创建默认的Mybatis代码和生成表，需要添加以下文件，目录结构为：

1、user.xml，这是要自动生成代码的一些配置　

<?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>
   <context id="user">
      <jdbcConnection driverClass="${database.driver}"
         connectionURL="${database.url}" userId="${database.username}"
         password="${database.password}" />
      <javaModelGenerator targetPackage="com.renruibin.springbootmybatis.pojo"
         targetProject="${targetProject}" />
      <sqlMapGenerator targetPackage="mapper"
         targetProject="${targetProjRsrc}" />
      <javaClientGenerator targetPackage="com.renruibin.springbootmybatis.dao"
         targetProject="${targetProject}" type="XMLMAPPER" />
        <table tableName="user" domainObjectName="User">
        </table>
   </context>
</generatorConfiguration>

javaModelGenerator：配置自动生成的pojo所在的位置

sqlMapGenerator：配置自动生成的mapper.xml文件所在的位置

javaClientGenerator：配置自动生成的mapper.java文件所在的位置

2、changleLog.xml，这是要自动生成表或者修改表结构的一些配置

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<databaseChangeLog xmlns="http://www.liquibase.org/xml/ns/dbchangelog"
   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
   xsi:schemaLocation="http://www.liquibase.org/xml/ns/dbchangelog http://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-3.1.xsd">
   <changeSet id="20190113" author="rrb">
      <createTable tableName="user" remarks="用户版">
         <column name="id" type="varchar(32)">
            <constraints nullable="false" primaryKey="true" />
         </column>
         <column name="username" remarks="用户名" type="varchar(50)" />
         <column name="password" remarks="密码" type="varchar(50)" />
         <column name="status" remarks="状态" type="int" />
         <column name="createtime" remarks="创建时间" type="TIMESTAMP" />
         <column name="edittime" remarks="修改时间" type="TIMESTAMP" />
      </createTable>
   </changeSet>
   <changeSet id="20190113-2" author="rrb">
      <dropColumn tableName="user" columnName="createtime"></dropColumn>
      <dropColumn tableName="user" columnName="edittime"></dropColumn>
   </changeSet>
</databaseChangeLog>

3、database.properties，这是数据源的一些配置

database.driver=com.mysql.jdbc.Driver
database.url=jdbc\:mysql\://127.0.0.1\:3306/springbootmybatis?useUnicode\=true&characterEncoding\=UTF-8
database.username=root
database.password=rrb

4、update&mybatis.xml，这是ant自动生成代码的配置

<project name="updateDatabase" default="mybatis">
   <property file="database.properties">
   </property>
   <property name="targetProject" location="..\src\main\java">
   </property>
   <property name="targetProjRsrc" location="..\src\main\resources">
   </property>
   <path id="jdbclib">
      <fileset dir="${basedir}\lib" includes="mysql-connector-java-5.1.23-bin.jar" />
   </path>
   <target name="mybatis" description="Generate the files">
      <taskdef name="mbgenerator" classname="org.mybatis.generator.ant.GeneratorAntTask">
         <classpath>
            <pathelement location="${basedir}\lib\mybatis-generator-core-1.3.2.jar" />
            <pathelement location="${basedir}\lib\generator-0.0.1-SNAPSHOT.jar" />
            <pathelement location="${basedir}\lib\mysql-connector-java-5.1.23-bin.jar" />
         </classpath>
      </taskdef>
      <mbgenerator overwrite="true" configfile="generator/user.xml"
         verbose="true">
         <propertyset>
            <propertyref name="database.driver" />
            <propertyref name="database.url" />
            <propertyref name="database.username" />
            <propertyref name="database.password" />
            <propertyref name="targetProject" />
            <propertyref name="targetProjRsrc" />
         </propertyset>
      </mbgenerator>
   </target>
</project>

5、updateDatabase.xml，这是ant自动生成表的配置<project name="updateDatabase" default="updateDatabase">

   <property file="database.properties">
   </property>
   <path id="jdbclib">
      <fileset dir="${basedir}\lib" includes="mysql-connector-java-5.1.23-bin.jar" />
   </path>
   <target name="updateDatabase">
      <fail unless="database.url">database.url not set</fail>
      <fail unless="database.username">database.username not set</fail>
      <fail unless="database.password">database.password not set</fail>
      <taskdef resource="liquibasetasks.properties">
         <classpath>
            <pathelement location="${basedir}\lib\snakeyaml-1.13.jar" />
            <pathelement location="${basedir}\lib\liquibase.jar" />
         </classpath>
      </taskdef>
       <updateDatabase
               changeLogFile="${basedir}\changeLog.xml"
               driver="${database.driver}"
               url="${database.url}"
               username="${database.username}"
               password="${database.password}"
               promptOnNonLocalDatabase="false"
               dropFirst="false"
               classpathref="jdbclib"
              loglevel="info"
       />
   </target>
</project>

四、

　　建立dao、service、controller，目录如下：

1、先看一下dao层的代码是如何编写的吧

@Mapper
public interface UserAtomMapper {
    List<User> finaAll();
}
@Mapper这个注解很关键，之前用的@Repository注解，但是与springboot整合之后，这个注解就不能用了，只有@Mapper注解的时候，才可以把这个类注入到service里。

2、看一下mapper层的xml文件是如何编写的

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" >
<mapper namespace="com.renruibin.springbootmybatis.dao.UserAtomMapper">
    <select id="finaAll" resultType="com.renruibin.springbootmybatis.pojo.User">
        select * from user
    </select>
</mapper>

3、看一下service层的代码

@Service
public class UserServiceImpl implements UserService {

    @Autowired
    private UserAtomMapper userAtomMapper;

    @Override
    public List<User> findAll() {
        return userAtomMapper.finaAll();
    }

4、看一下controller层的代码

@RestController
public class UserController {
    @Autowired
    private UserService userService;
    /**
     * 获取所有的用户
     * @return
     */
    @RequestMapping(value = "findAll",method = RequestMethod.GET)
    public List<User> findAll(){
        return userService.findAll();
    }
}
使用了注解@RestController，这个注解相当于两个注解，@Controller和@ResponseBody

五、

　　接下来可以测试，在浏览器输入localhost:8080/findAll