Spring4 已经不支持Ibatis了，但Ibatis的升级版Mybatis 封装了支持Spring4的组件mybatis-spring ，通过使用它们可以让你在Spring4中轻松地使用Mybatis。
gradle 设置
现在基本上新兴的java项目包括android都使用gradle 来做构建工具，gradle相比ant 来讲多了定义好的task，不需要每次都copy-paste相同的task到构建文件中，而相比maven 来说gradle比较灵活，可以像ant那样写简单的命令来进行copy或者mv等操作，总的来讲，gradle是集ant和maven优点于一身的新时代的构建工具。
要在工程中引入Mybatis的组件，需要现在gradle的构建文件中增加Mybatis的依赖包。
build.gradle 1
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dependencies {
compile 'org.mybatis:mybatis:3.2.8'
compile 'org.mybatis:mybatis-spring:1.2.2'
}
在spring中配置Mybatis
引入依赖包之后，需要在spring的配置文件中进行Mybatis的配置。
首先我们定义一个datasource，使用C3PO数据库连接池来进行管理。
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<bean id= "dataSource" class= "com.mchange.v2.c3p0.ComboPooledDataSource " destroy-method= "close" >
<property name= "driverClass" value= "com.mysql.jdbc.Driver" />
<property name= "jdbcUrl" value= "jdbc:mysql://192.168.36.10:3306/pebms" />
<property name= "user" value= "root" />
<property name= "password" value= "root" />
<property name= "acquireIncrement" value= "1" />
<property name= "initialPoolSize" value= "5" />
<property name= "maxPoolSize" value= "20" />
<property name= "minPoolSize" value= "5" />
<property name= "maxStatements" value= "100" />
<property name= "testConnectionOnCheckout" value= "true" />
</bean>
接着定义Mybatis的SessionFactory。
dataSource: 我们之前定义的数据源
transactionFactory: 事务管理配置
configLocation: Mybatis的具体文件地址
mapperLocations: Mybatis的SQL映射文件
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<bean id= "sqlSessionFactory" class= "org.mybatis.spring.SqlSessionFactoryBean" >
<property name= "dataSource" ref= "dataSource" />
<property name= "transactionFactory" >
<bean class= "org.apache.ibatis.transaction.managed.ManagedTransactionFactory" />
</property>
<property name= "configLocation" value= "classpath:sql-map-config.xml" />
<property name= "mapperLocations" value= "classpath:sql-mapping/farmer.xml" />
</bean>
sql-map-config.xml简单示例如下，设置了缓存，延迟加载，超时时间等属性，更多的配置可以参照这里 。
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<?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= "cacheEnabled" value= "true" />
<setting name= "lazyLoadingEnabled" value= "true" />
<setting name= "multipleResultSetsEnabled" value= "true" />
<setting name= "useColumnLabel" value= "true" />
<setting name= "defaultExecutorType" value= "REUSE" />
<setting name= "defaultStatementTimeout" value= "25000" />
</settings>
</configuration>
farmer.xml 1
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<?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.farmer.baton.repo.FarmerMapper" >
<insert id= "add-new-farmer" parameterType= "com.farmer.baton.model.Farmer" >
insert into farmers(id, name, age) values (
#{id},
#{name},
#{age}
)
</insert>
</mapper>
继续在spring.xml文件里进行Mybatis的配置，定义Mybatis的DAO(数据库访问对象)和事务控制，这里配置了DAO的包路径。
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<bean class= "org.mybatis.spring.mapper.MapperScannerConfigurer" >
<property name= "basePackage" value= "com.farmer.baton.repo" />
<property name= "sqlSessionFactoryBeanName" value= "sqlSessionFactory" />
</bean>
<bean id= "transactionManager" class= "org.springframework.jdbc.datasource.DataSourceTransactionManager" >
<property name= "dataSource" ref= "dataSource" />
</bean>
Mybatis responsitory编写
在前面的spring里面配置了DAO的包路径，我们下面要做的东西就比较就简单了。
先在DAO包路径下定义一个DAO接口，这里不需要实现具体的内容，具体的sql在我们的映射文件里面体现。
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package com . farmer . baton . repo ;
import com.farmer.baton.model.Farmer ;
import java.util.List ;
public interface FarmerRepository {
List < Farmer > findAll ();
}
在xml映射文件里面实现findAll方法，这里要注意方法的签名必须和映射文件的sql的id一致，包括方法名和id一致，方法参数类型和sql的parameterType一致，方法返回类型和sql的resultType或resultMap类型一致。
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<?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.farmer.baton.repo.FarmerRepository" >
<resultMap id= "baseResultMap" type= "com.farmer.baton.model.Farmer" >
<id column= "id" property= "id" />
<result column= "name" property= "name" />
<result column= "age" property= "age" />
</resultMap>
<select id= "findAll" resultMap= "baseResultMap" >
select id as id,
name as name,
age as age
from farmers
</select>
</mapper>
写好Repository和映射SQL就可以了，程序在调用Repository方法的时候就会自动执行到相关的SQL。
事务控制
Mybatis的事务控制使用Spring的事务配置即可，配置如下:
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<beans xmlns:tx= "http://www.springframework.org/schema/tx"
http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.0.xsd" >
...
<tx:annotation-driven/>
...
然后在调用Repository的方面前面加上Transactional标签，如下所示:
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@Service
public class FarmerService {
@Autowired
private FarmerRepository farmerRepository ;
@Transactional
public void updateTwoFarmers ( Farmer farmer1 , Farmer farmer2 ) {
farmerRepository . updateZhangsan ( farmer1 );
farmerRepository . updateWangwu ( farmer2 );
}
}
Mybatis语法
Mybatis的语法在功能上有了很大的改进，具体体现在SQL映射文件中。
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<insert id= "add-new-farmer" parameterType= "com.farmer.baton.model.Farmer" >
insert into farmers(id, name, age) values
<foreach collection= "farmers" item= "farmer" separator= "," >
(
#{id},
#{name},
#{age}
)
</foreach>
</insert>
FarmerRepository 1
void addFarmers ( @Param ( "farmers" ) List < Farmer > farmers );
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<resultMap id= "farmer" type= "com.farmer.baton.model.Farmer" >
<id column= "id" property= "id" />
<result column= "name" property= "name" />
<result column= "age" property= "age" />
</resultMap>
<select id= "selectFarmersByNameAndAge" parameterType= "map" resultMap= "farmer" >
select id as id,
name as name,
age as age
from farmers
where name = #{name}
and age = #{age}
</select>
FarmerRepository.java 1
List < Farmer > selectFarmersByNameAndAge ( @Param ( "name" ) String name , @Param ( "age" ) int age );
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<resultMap id= "farmer" type= "com.farmer.baton.model.Farmer" >
<id column= "id" property= "id" />
<result column= "name" property= "name" />
<result column= "age" property= "age" />
<collection property= "farmland" ofType= "com.farmer.baton.model.Farmland" >
<result column= "size" property= "size" />
</collection>
</resultMap>
<select id= "selectFarmersAndFarmlands" resultMap= "farmer" >
select id as id,
name as name,
age as age
from farmers a
left outer join farmerlands b on a.id = b.farmer_id
</select>
FarmerRepository.java 1
List < Farmer > selectFarmersAndFarmlands ();
Farmer.java 1
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private String name ;
private int age ;
private List < Farmland > farmlands ;
具体的Demo可以参考我的github工程spring4-mybatis 。
