myBatis配置

Posted 2020-10-13

1.读取全局配置文件String resource="mybatis-config.xml";

                                InputStream is=Resources.getResourceAsStream(resource);

2.创建SqlSessionFactory对象

      SqlSessionFactory factory=new SqlSessionFactoryBulider().build(is);

3.创建SqlSession 调用Mapper

      SqlSession sqlSession=factory.openSession();

      int count=sqlSession.selectOne("方法")；

      sqlSession.close();

 

 

 

配置文件mybatis-config.xml

（先后顺序有要求

1.properties-2.settings-3.typeAliases（别名）-4.typeHandlers(类型处理器)-5.objectFactory(对象工厂)-6.plugins(插件)-7.environments(环境）-8.mappers（映射器））

<?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>

<!--引入database.properties文件-->

<properties resource="database.properties"/>
<settings>
<setting name="logImpl" value="LOG4J" />
</settings>

<typeAliases>

 <typeAlias alias="user" type="cn.smbms.pojo.User">

</typeAliases>

<environments default="abc">
<!-- default跟id对应 -->
<environment id="abc">
<transactionManager type="JDBC" />
<dataSource type="POOLED">
<property name="driver" value="${driver}" />
<property name="url" value="${url}" />
<property name="username" value="${username}" />
<property name="password" value="${password}" />
</dataSource>
</environment>
</environments>

<mappers>
<mapper resource="Mapper/BillMapper.xml" />

</mappers>
</configuration>

 

 

 

 

mapper

1.parameterType 传入参数类型

2.resultMap 自定义映射 (外键操作用到)

会自动映射匹配，关闭

<settings><setting name="autoMappingBehavior" value="None"></settings>

                                                                                            PATYIAL 或FULL（包含内部嵌套）

                <resultMap type="cn.smbms.pojo.User" id="UserList" >
                  <result property="id" column="id" />
                  <result property="userCode" column="userCode" />
                  <result property="userName" column="userName" />
                  <result property="phone" column="phone" />
                  <result property="birthday" column="birthday" />
                </resultMap>

 

复杂类型可以嵌套(只适用1对1)

<association property="role" javaType="Role">           或<collection property="addressList" ofType="Address">   (区别collection是一个集合列表)

<result XXX/>

</association>

3.resultType 自动映射

4.开启二级缓存

<settings><setting name="cacheEnabled" value="true"/></settings>