javaee spring整合mybatis-编程知识

案例一

包含dao层

创建maven webapp项目

maven仓库需要改为阿里云
在这里插入图片描述

引入依赖

<?xml version="1.0" encoding="UTF-8"?><project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"><modelVersion>4.0.0</modelVersion><groupId>org.example</groupId><artifactId>testSSM</artifactId><version>1.0-SNAPSHOT</version><packaging>war</packaging><name>testSSM Maven Webapp</name><!-- FIXME change it to the project's website --><url>http://www.example.com</url><properties><project.build.sourceEncoding>UTF-8</project.build.sourceEncoding><maven.compiler.source>1.7</maven.compiler.source><maven.compiler.target>1.7</maven.compiler.target></properties><dependencies><dependency><groupId>junit</groupId><artifactId>junit</artifactId><version>4.11</version><scope>test</scope></dependency><!-- 1.导入Spring相关的jar包 --><dependency><groupId>org.springframework</groupId><artifactId>spring-context</artifactId><version>4.3.18.RELEASE</version></dependency><dependency><groupId>org.springframework</groupId><artifactId>spring-core</artifactId><version>4.3.18.RELEASE</version></dependency><dependency><groupId>org.springframework</groupId><artifactId>spring-beans</artifactId><version>4.3.18.RELEASE</version></dependency><dependency><groupId>org.springframework</groupId><artifactId>spring-context-support</artifactId><version>4.3.18.RELEASE</version></dependency><!-- 导入mybatis的jar包 --><dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId><version>5.1.37</version></dependency><dependency><groupId>org.mybatis</groupId><artifactId>mybatis</artifactId><version>3.4.6</version></dependency><dependency><groupId>com.mchange</groupId><artifactId>c3p0</artifactId><version>0.9.5.2</version></dependency><!-- 配置日志信息--><dependency><groupId>log4j</groupId><artifactId>log4j</artifactId><version>1.2.17</version></dependency><!-- spring 整合 mybatis--><dependency><groupId>org.mybatis</groupId><artifactId>mybatis-spring</artifactId><version>1.3.0</version></dependency><dependency><groupId>org.springframework</groupId><artifactId>spring-jdbc</artifactId><version>4.3.18.RELEASE</version></dependency></dependencies><build><resources><resource><!-- 将Mapper的映射文件拷贝出来 --><directory>src/main/java</directory><includes><include>**/*.xml</include></includes><filtering>true</filtering></resource></resources><finalName>testSSM</finalName><pluginManagement><!-- lock down plugins versions to avoid using Maven defaults (may be moved to parent pom) --><plugins><plugin><artifactId>maven-clean-plugin</artifactId><version>3.1.0</version></plugin><!-- see http://maven.apache.org/ref/current/maven-core/default-bindings.html#Plugin_bindings_for_war_packaging --><plugin><artifactId>maven-resources-plugin</artifactId><version>3.0.2</version></plugin><plugin><artifactId>maven-compiler-plugin</artifactId><version>3.8.0</version></plugin><plugin><artifactId>maven-surefire-plugin</artifactId><version>2.22.1</version></plugin><plugin><artifactId>maven-war-plugin</artifactId><version>3.2.2</version></plugin><plugin><artifactId>maven-install-plugin</artifactId><version>2.5.2</version></plugin><plugin><artifactId>maven-deploy-plugin</artifactId><version>2.8.2</version></plugin></plugins></pluginManagement></build>
</project>

spring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:jdbc="http://www.springframework.org/schema/jdbc"xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd http://www.springframework.org/schema/jdbc http://www.springframework.org/schema/jdbc/spring-jdbc.xsd"><!-- 1.扫描包中的注解 --><context:component-scan base-package="com.test" /><!--导入db.properties文件--><context:property-placeholder location="classpath:db.properties" /><!--创建了数据源 --><bean id="comboPooledDataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource"><property name="driverClass" value="${driverClass}" /><property name="jdbcUrl" value="${url}"/><property name="user" value="${user}" /><property name="password" value="${password}" /></bean><!--创建SqlSessionFactory对象 --><bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean"><property name="dataSource" ref="comboPooledDataSource" /><property name="configLocation" value="classpath:sqlMapConfig.xml" /></bean><!-- 扫描mapper文件 生成代理对象 替代之前dao层的操作 --><bean class="org.mybatis.spring.mapper.MapperScannerConfigurer"><property name="basePackage" value="com.test.mapper" /></bean></beans>

数据库信息

driverClass=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306/itstar
user=itstar
password=yyy123456

mybatis配置文件

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE configurationPUBLIC "-//mybatis.org//DTD Config 3.0//EN""http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration><!--配置db.properties  转移到spring中--><!--<properties resource="db.properties" />--><!-- 配置日志管理 --><settings><setting name="logImpl" value="STDOUT_LOGGING"/></settings><!-- 设置别名--><typeAliases><package name="com.test.pojo" /></typeAliases><!-- 转移到spring配置文件中 --><!--<environments default="development">--><!--<environment id="development">--><!--<transactionManager type="JDBC"/>--><!--<dataSource type="POOLED">--><!--<property name="driver" value="${driverClass}"/>--><!--<property name="url" value="${url}"/>--><!--<property name="username" value="${user}"/>--><!--<property name="password" value="${password}"/>--><!--</dataSource>--><!--</environment>--><!--</environments>--><!--注册mapper文件 转移到spring中--><!--<mappers>--><!--<package name="com.test.mapper" />--><!--</mappers>--></configuration>

dao层

package com.test.dao;import com.test.pojo.Items;import java.util.List;public interface IItemsDao {public List<Items> selectItems();
}

package com.test.dao.impl;import com.test.dao.IItemsDao;
import com.test.mapper.ItemsMapper;
import com.test.pojo.Items;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;import java.util.List;//实现类
@Component
public class ItemsDao implements IItemsDao {@Autowiredprivate SqlSessionFactory sqlSessionFactory;public SqlSessionFactory getSqlSessionFactory() {return sqlSessionFactory;}public void setSqlSessionFactory(SqlSessionFactory sqlSessionFactory) {this.sqlSessionFactory = sqlSessionFactory;}//转移到Spring的配置文件中  让Spring创建SqlSessionFactory对象
//    public ItemsDao()
//    {
//        InputStream inputStream=this.getClass().getClassLoader().getResourceAsStream("sqlMapConfig.xml");
//
//        SqlSessionFactoryBuilder sqlSessionFactoryBuilder=new SqlSessionFactoryBuilder();
//
//        this.sqlSessionFactory= sqlSessionFactoryBuilder.build(inputStream);
//    }//查询所有的商品信息@Overridepublic List<Items> selectItems() {SqlSession sqlSession= sqlSessionFactory.openSession();ItemsMapper itemsMapper= sqlSession.getMapper(ItemsMapper.class);return itemsMapper.selectItems();}
}

mapper

package com.test.mapper;import com.test.pojo.Items;import java.util.List;//创建一个接口  代理ItemsMapper.xml文件
public interface ItemsMapper {public List<Items> selectItems();
}

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapperPUBLIC "-//mybatis.org//DTD Mapper 3.0//EN""http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.test.mapper.ItemsMapper"><!-- 查询 --><select id="selectItems" resultType="Items">select * from items</select></mapper>

service层

package com.test.service;import com.test.pojo.Items;import java.util.List;public interface IItemsService {public List<Items> selectItems();
}

package com.test.service.impl;import com.test.dao.IItemsDao;
import com.test.pojo.Items;
import com.test.service.IItemsService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;import java.util.List;//service层的实现类@Service
public class ItemsService implements IItemsService {@Autowiredprivate IItemsDao itemsDao;public IItemsDao getItemsDao() {return itemsDao;}public void setItemsDao(IItemsDao itemsDao) {this.itemsDao = itemsDao;}@Overridepublic List<Items> selectItems() {return itemsDao.selectItems();}
}

测试类

package com.test.service;import com.test.pojo.Items;
import com.test.service.impl.ItemsService;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;import java.util.List;public class TestItemsService {@Testpublic void test(){//测试service层的查询方法ApplicationContext applicationContext=new ClassPathXmlApplicationContext("applicationContext.xml");IItemsService itemsService= applicationContext.getBean("itemsService",IItemsService.class);List<Items> itemsList= itemsService.selectItems();System.out.println(itemsList);}
}

案例二

省略dao层，由spring代替

在案例一的基础上，修改spring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:jdbc="http://www.springframework.org/schema/jdbc"xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd http://www.springframework.org/schema/jdbc http://www.springframework.org/schema/jdbc/spring-jdbc.xsd"><!-- 1.扫描包中的注解 --><context:component-scan base-package="com.test" /><!--导入db.properties文件--><context:property-placeholder location="classpath:db.properties" /><!--创建了数据源 --><bean id="comboPooledDataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource"><property name="driverClass" value="${driverClass}" /><property name="jdbcUrl" value="${url}"/><property name="user" value="${user}" /><property name="password" value="${password}" /></bean><!--创建SqlSessionFactory对象 --><bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean"><property name="dataSource" ref="comboPooledDataSource" /><property name="configLocation" value="classpath:sqlMapConfig.xml" /></bean><!-- 扫描mapper文件 生成代理对象 替代之前dao层的操作 --><bean class="org.mybatis.spring.mapper.MapperScannerConfigurer"><property name="basePackage" value="com.test.mapper" /></bean></beans>

删除dao层

修改service层

package com.test.service.impl;import com.test.mapper.ItemsMapper;
import com.test.pojo.Items;
import com.test.service.IItemsService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;import java.util.List;//service层的实现类@Service
public class ItemsService implements IItemsService {//spring会帮我们创建一个代理对象（ 实现了ItemsMapper接口的），代理对象代理的是dao层的功能@Autowiredprivate ItemsMapper itemsMapper;public ItemsMapper getItemsMapper() {return itemsMapper;}public void setItemsMapper(ItemsMapper itemsMapper) {this.itemsMapper = itemsMapper;}@Overridepublic List<Items> selectItems() {return itemsMapper.selectItems();}
}