MyBatis学习笔记（三）

2019-11-08 02:58:07

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MyBatis学习笔记（三）

常用批量操作，SPRing与myBatis整合，简化配置

个人笔记，如有错误，恳请批评指正。

常用批量操作

批量新增部门

映射文件定义SQL

<sql id="key"> <trim suffixOverrides=","> dept_name, dept_address, </trim> </sql> <insert id="insertDeptList"> insert into dept( <include refid="key"></include> ) values <foreach collection="list" item="dept" separator=","> (#{dept.deptName},#{dept.deptAddress}) </foreach> </insert>

编写批量添加部门方法

数据操作类定义批量添加部门的方法

public int insertDeptList(List list){ int i = 0; try { session = MybatisSessionFactory.getSession(); i = session.insert("cn.ustb.entity.DeptMapper.insertDeptList", list); session.commit(); } catch (Exception e) { e.printStackTrace(); session.rollback(); } finally{ MybatisSessionFactory.closeSession(); } return i; }

批量删除部门

映射文件定义SQL

<delete id="deleteDeptList" parameterType="string"> delete from dept where dept_id in ( <foreach collection="array" item="id" separator=","> #{id} </foreach> ); </delete>

编写批量删除部门的方法

public int deleteDeptList(String[] ids){ int i = 0; try { session = MybatisSessionFactory.getSession(); i = session.delete("cn.ustb.entity.DeptMapper.deleteDeptList", ids); session.commit(); } catch (Exception e) { e.printStackTrace(); session.rollback(); } finally{ MybatisSessionFactory.closeSession(); } return i; }

批量修改员工信息

修改mybatis-config.xml文件

支持上有点麻烦，需要修改mybatis-config.xml文件相关数据库连接的信息（主要url），以支持批量更新 <environments default="development"> <environment id="development"> <transactionManager type="JDBC" /> <dataSource type="POOLED"> <property name="driver" value="com.MySQL.jdbc.Driver"></property> <property name="url" value="jdbc:mysql://localhost:3306/mybatis?useUnicode=true&characterEncoding=UTF-8&allowMultiQueries=true" /> <property name="username" value="root"></property> <property name="passWord" value="root"></property> </dataSource> </environment> <environment id="test"> <transactionManager type=""/> <dataSource type=""></dataSource> </environment> </environments>

配置批量更新的sql

<update id="updateDeptList"> <foreach collection="list" item="dept" separator=";"> update dept <set> <if test="dept.deptName!=null">dept_name = #{dept.deptName},</if> <if test="dept.deptAddress!=null">dept_address = #{dept.deptAddress},</if> </set> where dept_id = #{dept.deptId} </foreach> </update>

编写批量更新部门的方法

public int updateDeptList(List list){ int i = 0; try { session = MybatisSessionFactory.getSession(); i = session.update("cn.ustb.entity.DeptMapper.updateDeptList", list); session.commit(); } catch (Exception e) { e.printStackTrace(); session.rollback(); } finally{ MybatisSessionFactory.closeSession(); } return i; }

Spring+myBatis整合

准备工作

新建项目并导入jar包配置mybatis-config.xml创建库及表创建实体编写映射文件，修改mybatis-config.xml内容进行简单测试（除了导入spring相关jar包外，以上内容可能直接使用上一章节内容）

配置applicationContext.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:tx="http://www.springframework.org/schema/tx" xmlns:aop="http://www.springframework.org/schema/aop" xmlns:context="http://www.springframework.org/schema/context" xmlns:p="http://www.springframework.org/schema/p" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.0.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.0.xsd">  <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource"> <property name="driverClass" value="com.mysql.jdbc.Driver" /> <property name="jdbcUrl" value="jdbc:mysql://localhost:3306/mybatis?useUnicode=true&characterEncoding=UTF-8" /> <property name="user" value="root" /> <property name="password" value="root" /> </bean>  <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean"> <property name="dataSource" ref="dataSource" /> <property name="configLocation" value="classpath:myBatis-config.xml" /> <property name="mapperLocations" value="classpath:cn/ustb/entity/*.xml"/> </bean>  <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager"> <property name="dataSource" ref="dataSource"/> </bean>  <bean id="deptDao" class="cn.ustb.dao.impl.DeptDaoImpl"> <property name="sqlSessionTemplate" ref="sqlSessionTemplate"></property> </bean>  <bean id="sqlSessionTemplate" class="org.mybatis.spring.SqlSessionTemplate"> <constructor-arg name="sqlSessionFactory" ref="sqlSessionFactory"/> </bean> </beans>

修改myBatis-config.xml

去掉数据源配置

<?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> <typeAliases> <typeAlias type="cn.ustb.entity.Dept" alias="Dept" /> </typeAliases> <mappers> <mapper resource="cn/ustb/entity/DeptMapper.xml" /> </mappers></configuration>

编写dao层接口及实现

DeptDao.java

public interface DeptDao { //根据部门ID查询部门信息 public Dept selectOne(int deptId);}

修改接口实现类：DeptDaoImpl.java

public class DeptDaoImpl { private SqlSessionTemplate sqlSessionTemplate; public SqlSessionTemplate getSqlSessionTemplate() { return sqlSessionTemplate; } public void setSqlSessionTemplate(SqlSessionTemplate sqlSessionTemplate) { this.sqlSessionTemplate = sqlSessionTemplate; } public Dept selectOne(int deptId){ Dept dept = null; dept = sqlSessionTemplate.selectOne("cn.ustb.entity.DeptMapper.selectOne", deptId); return dept; }}

编写业务层代码业务层接口略，这里只写业务层实现类：DeptServiceImpl.java

public class DeptServiceImpl { private DeptDao deptDao; public DeptDao getDeptDao() { return deptDao; } @Resource public void setDeptDao(DeptDao deptDao) { this.deptDao = deptDao; } public Dept selectOne(int id){ return deptDao.selectOne(id); } public int insertDept(Dept dept){ return deptDao.insertDept(dept); }}

配置bean信息到sping配置文件

<bean id="deptDao" class="cn.ustb.dao.impl.DeptDaoImpl" > <property name="sqlSessionTemplate" ref="sqlSessionTemplate"/></bean><bean id="deptService" class="cn.ustb.service.impl.DeptServiceImpl"> <property name="deptDao" ref="deptDao"/></bean>

简化配置

扫描式加载SQL映射文件

修改myBatis-config.xml文件，去掉配置

<?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> <typeAliases> <typeAlias type="cn.ustb.entity.Dept" alias="Dept" /> </typeAliases>  </configuration>

修改applicationContext.xml,为SqlSessionFactoryBean设置mapperLocations属性

<bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean"> <property name="dataSource" ref="dataSource" /> <property name="configLocation" value="classpath:myBatis-config.xml" />  <property name="mapperLocations" value="classpath:cn/ustb/entity/*.xml"/> </bean>

MapperScannerConfigurer简化配置

1. 在spring配置文件中添加MapperScannerConfigurer 配置并去掉所有的Dao接口实现类配置

<bean class="org.mybatis.spring.mapper.MapperScannerConfigurer"> <property name="sqlSessionFactory" ref="sqlSessionFactory"/> <property name="basePackage" value="cn.ustb.dao"/> </bean>    <bean id="deptService" class="cn.ustb.service.impl.DeptServiceImpl">   </bean>

2. 检查或修改DeptMapper.xml文件

注意：命名空间+id和接口+方法名一致

<?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="cn.ustb.dao.DeptDao"> <resultMap id="deptResultMap" type="Dept"> <id property="deptId" column="dept_id" /> <result property="deptName" column="dept_name" /> <result property="deptAddress" column="dept_address" /> </resultMap>  <select id="selectOne" parameterType="int" resultMap="deptResultMap"> select * from dept where dept_id=#{id} </select></mapper>