Spring-MyBatis整合简单例子及个人的经验杂谈

谁借莪１个温暖的怀抱￠ 2022-07-13 11:42 164阅读 0赞

## 所需jar包：Spring所需包、MyBatis所需包、mybatis-spring-1.x.x.jar(Spring与Mybatis整合包，需额外下载) ##

该文章主要分享一些自己的经验，所以一些配置可能不会解释

**配置流程(个人觉得把逻辑顺序理清后需要记忆性的方面并不会太多):**

**![Center][]**

**以下是位于WEB-INF下的applicationContext.xml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:c="http://www.springframework.org/schema/c"
    	xmlns:context="http://www.springframework.org/schema/context" xmlns:p="http://www.springframework.org/schema/p"
    	xmlns:tx="http://www.springframework.org/schema/tx"
    	xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.2.xsd
    		http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.3.xsd
    		http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.3.xsd">
    
    	<context:annotation-config></context:annotation-config>
    	
    	<context:component-scan base-package="pers"
    		use-default-filters="false">
    		<context:include-filter type="annotation"
    			expression="org.springframework.stereotype.Repository" />
    		<context:include-filter type="annotation"
    			expression="org.springframework.stereotype.Service" />
    	</context:component-scan>
    
    	<bean id="dataSource" class="org.springframework.jndi.JndiObjectFactoryBean"
    		p:jndiName="java:comp/env/jdbc/mysql"></bean>
    
    	<bean id="transactionManager"
    		class="org.springframework.jdbc.datasource.DataSourceTransactionManager"
    		p:dataSource-ref="dataSource"></bean>
    
    	<bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean"
    		p:dataSource-ref="dataSource" p:configLocation="classpath:mybatis-config.xml"></bean>
    
    	<bean id="sqlSessionTemplate" class="org.mybatis.spring.SqlSessionTemplate"
    		c:_-ref="sqlSessionFactory"></bean>
    
    	<bean class="org.mybatis.spring.mapper.MapperScannerConfigurer"
    		p:basePackage="pers.dao" p:sqlSessionFactoryBeanName="sqlSessionFactory"
    		p:sqlSessionTemplateBeanName="sqlSessionTemplate">
    	</bean>
    
    	<tx:annotation-driven />
    </beans>

①由于使用的是JNDI数据源所以还需在tomcat的context.xml文件中添加如下配置

![Center 1][]

本以为配置数据源应该都该在spring-jdbc-xxx的jar下包找的(Eclipse ALT+SHIFT+T可以快捷查询具体类在哪个jar包下)，但可能由于jndi的数据源配置需在服务器中配置(这里是Tomcat服务器中的context.xml负责配置)，所以把它放到spring-context-xxx.jar包中了

②SqlSessionFactoryBean：负责生成SqlSessionFactory，位于整合的mybatis-spring整合包中(由于该整合包是由MyBatis开发所以以mybatis为前缀，因Spring3发布时Mybatis3尚未完成，所以MyBatis社区自己进行整合)

![Center 2][]

个人比较喜欢看着左侧的属性栏进行Spring的属性装配，因为觉得能找到就没必要去记那么多没必要的属性。看到该类的属性相信大家都发现了mybatis的配置文件中的所有标签这里都有，也就是说mybatis配置文件的所有标签属性都可以通过该类配置，但个人不推荐所以只说个人喜欢的方式。我配置时看到哪个属性是我在配置文件中已经配置好的就直接填充，如dataSource。

configLocation:mybatis配置文件的所在位置，配置该属性后会根据位置解析文件然后为相应的标签属性赋值，具体方法为该类中的buildSqlSessionFactory()方法，有兴趣的可以去看看。

谈一下FactoryBean：Spring中的xxxFactoryBean都继承了Spring的FactoryBean，生成的bean一般为实现时的泛型，如上图中泛型为SqlSessionFactory，固配置该SqlSessionFactoryBean的实际bean是SqlSessionFactory实例，所以配置SqlSessionTemplate中的sqlSessionFactory属性时将用bean id="sqlSessionFactory"将用该SqlSessionFactory实例填充，上面JndiObjectFactoryBean亦然。看一下源码注解：

![Center 3][]

粗略讲一下第一段大意：实现该接口的对象将会作为一个为了对象而公开的工厂，而不是直接作为一个bean实例进行公开(如配置class为SqlSessionFactoryBean后生成(公开)的bean为SqlSessionFactory而不是SqlSessionFactoryBean)，返回bean的方法是getObject()，即getObject返回的bean是什么则工厂bean生成的bean就是什么，一般设定为泛型的实例

③SqlSessionTemplate：一个模板类，通过调用SqlSession来完成工作，SqlSession由SqlSessionFactory负责生成，在Mybatis-Spring项目中它是一个核心类，主要的2个属性：

sqlSessionFactory:该类没有无参构造函数，即代表该属性必须作为构造器参数配置

executeorType：执行器，取值范围为SIMPLE、REUSE、BATCH，等同于mybatis配置文件中的setting的defaultExecutorType，可作为构造函数的第二个参数，但个人建议还是在mybatis配置文件中配置

该类具体构造方法如下图：

![Center 4][]

④MapperScannerConfigurer(数目少的话可以用MapperFactoryBean，这里不做介绍)：采用自动扫描形式配置映射器,主要属性：

basePackage：指定让Spring自动扫描什么包，它会逐层深入扫描

annotationClass：表示如果该类被这个注解标识的时候才进行扫描(我例子中设置的是Repository，该注解一般用于标识DAO层)

sqlSessionFactoryBeanName：指定在Spring中定义sqlSessionFactory的bean的名称。如果它被定义，sqlSessionFactory将不起作用。

sqlSessionTemplateBeanName：指定在Spring中定义sqlSessionTemplate的bean的名称。如果它被定义，sqlSessionTemplate将不起作用。

makerInterface：指定实现了什么接口就认为它是Mapper，需提供一个公共接口去标记。

该类中还有sqlSessionFactory与sqlSessionTemplate这两个属性，但个人建议以sqlSessionFactoryBeanName、sqlSessionTemplateBeanName替代，因：

![Center 5][]![Center 6][]

这两个方法都已标识过时，代表着可能过几个版本就会消失掉。

以下是该例子的相关代码，如果只对流程有兴趣的可以直接跳到最底Spring MVC层的简单配置

![Center 7][]![Center 8][]

Role.java

package pers.vo;
    
    import java.io.Serializable;
    
    public class Role implements Serializable{
    	private static final long serialVersionUID = 1L;
    	private Integer id;
    	private String roleName;
    	private String note;
    
    	@Override
    	public String toString() {
    		return "Role [id=" + id + ", roleName=" + roleName + ", note=" + note + "]";
    	}
    
    	public Role() {
    	}
    
    	public Role(String roleName, String note) {
    		super();
    		this.roleName = roleName;
    		this.note = note;
    	}
    
    	public Integer getId() {
    		return id;
    	}
    
    	public void setId(Integer id) {
    		this.id = id;
    	}
    
    	public String getRoleName() {
    		return roleName;
    	}
    
    	public void setRoleName(String roleName) {
    		this.roleName = roleName;
    	}
    
    	public String getNote() {
    		return note;
    	}
    
    	public void setNote(String note) {
    		this.note = note;
    	}
    
    }

RoleDAO.java

package pers.dao;
    
    import java.util.List;
    
    import org.apache.ibatis.session.RowBounds;
    import org.springframework.stereotype.Repository;
    
    import pers.vo.Role;
    
    @Repository
    public interface RoleDAO {
    	Role findRoleById(int id);
    
    	int insertRole(Role role);
    
    	int deleteRoleById(int id);
    
    	int updateRole(Role role);
    
    	List<Role> findRolesByKeyName(String name);
    
    	List<Role> findAllRoles(RowBounds rowBounds);
    }

RoleService.java

package pers.service;
    
    import java.util.List;
    
    import pers.vo.Role;
    
    public interface RoleService {
    	Role findRoleById(int id);
    
    	int insertRole(Role role);
    
    	int deleteRoleById(int id);
    
    	int updateRole(Role role);
    
    	List<Role> findRolesByKeyName(String name);
    
    	List<Role> findAllRoles(int start,int limit);
    }

RoleServiceImpl.java

package pers.service.impl;
    
    import java.util.List;
    
    import org.apache.ibatis.session.RowBounds;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.stereotype.Service;
    import org.springframework.transaction.annotation.Propagation;
    import org.springframework.transaction.annotation.Transactional;
    
    import pers.dao.RoleDAO;
    import pers.service.RoleService;
    import pers.vo.Role;
    
    @Service
    public class RoleServiceImpl implements RoleService {
    	@Autowired(required=false)
    	private RoleDAO roleDAO;
    	
    	@Override
    	@Transactional(propagation = Propagation.SUPPORTS)
    	public Role findRoleById(int id) {
    		return roleDAO.findRoleById(id);
    	}
    
    	@Override
    	@Transactional(propagation = Propagation.REQUIRED)
    	public int insertRole(Role role) {
    		return roleDAO.insertRole(role);
    	}
    
    	@Override
    	@Transactional(propagation = Propagation.REQUIRED)
    	public int deleteRoleById(int id) {
    		return roleDAO.deleteRoleById(id);
    	}
    
    	@Override
    	@Transactional(propagation = Propagation.REQUIRED)
    	public int updateRole(Role role) {
    		return roleDAO.updateRole(role);
    	}
    
    	@Override
    	@Transactional(propagation = Propagation.SUPPORTS)
    	public List<Role> findRolesByKeyName(String name) {
    		return roleDAO.findRolesByKeyName(name);
    	}
    
    	@Override
    	@Transactional(propagation = Propagation.SUPPORTS)
    	public List<Role> findAllRoles(int start, int limit) {
    		return roleDAO.findAllRoles(new RowBounds(start, limit));
    	}
    
    }

RoleController.java

package pers.controller;
    
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.stereotype.Controller;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RequestParam;
    import org.springframework.web.bind.annotation.ResponseBody;
    
    import pers.service.RoleService;
    import pers.vo.Role;
    
    @Controller
    public class RoleController {
    	@Autowired
    	private RoleService roleService;
    
    	public void setRoleService(RoleService roleService) {
    		this.roleService = roleService;
    	}
    
    	public RoleController() {
    	}
    	
    	@RequestMapping("/role/getRole")
    	@ResponseBody
    	public Role getRole(@RequestParam("id") int id) {
    		Role role = roleService.findRoleById(id);
    		System.out.println(role);
    		return role;
    	}
    }

mybatis-config.xml

<?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="mapUnderscoreToCamelCase" value="true" />
    		<setting name="aggressiveLazyLoading" value="false" />
    		<setting name="lazyLoadingEnabled" value="true" />
    		<setting name="useGeneratedKeys" value="true" />
    		<setting name="defaultExecutorType" value="REUSE" />
    		<setting name="defaultStatementTimeout" value="25000" />
    	</settings>
    	<typeAliases>
    		<package name="pers.vo" />
    	</typeAliases>
    	<mappers>
    		<mapper resource="mapper/role.xml" />
    	</mappers>
    </configuration>

Role.xml

<?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="pers.dao.RoleDAO">
    	<cache eviction="LRU" flushInterval="100000"></cache>
    	<select id="findRoleById" resultType="role">
     		<![CDATA[select id,role_name,note from tb_role where id=#{id}]]>
    	</select>
    	<select id="findRolesByKeyName" resultType="role">
    		<bind name="name_pattern" value="'%'+ name + '%'"/>
    		<![CDATA[select id,role_name,note from tb_role where role_name like #{name_pattern}]]>
    	</select>
    	<select id="findAllRoles" resultType="role">
    		<![CDATA[select id,role_name,note from tb_role]]>
    	</select>
    	<insert id="insertRole" parameterType="role">
    		<![CDATA[insert into tb_role(role_name,note) values (#{roleName},#{note})]]>
    	</insert>
    	<update id="updateRole" parameterType="role">
    		<![CDATA[select role_name,note from tb_role where id=#{id}]]>
    	</update>
    	<delete id="deleteRoleById">
    		<![CDATA[delete from tb_role where id=#{id}]]>
    	</delete>
    </mapper>

web.xml

<?xml version="1.0" encoding="UTF-8"?>
    <web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    	xmlns="http://xmlns.jcp.org/xml/ns/javaee"
    	xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"
    	id="WebApp_ID" version="3.1">
    	<display-name>SM_Integration</display-name>
    
    	<listener>
    		<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
    	</listener>
    
    	<servlet>
    		<servlet-name>springDispatcherServlet</servlet-name>
    		<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    		<init-param>
    			<param-name>contextConfigLocation</param-name>
    			<param-value>/WEB-INF/dispatcher-servlet.xml</param-value>
    		</init-param>
    		<load-on-startup>1</load-on-startup>
    	</servlet>
    	<servlet-mapping>
    		<servlet-name>springDispatcherServlet</servlet-name>
    		<url-pattern>/</url-pattern>
    	</servlet-mapping>
    
    	<welcome-file-list>
    		<welcome-file>index.jsp</welcome-file>
    	</welcome-file-list>
    </web-app>

MVC配置文件dispatcher-servlet.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:aop="http://www.springframework.org/schema/aop"
    	xmlns:c="http://www.springframework.org/schema/c" xmlns:context="http://www.springframework.org/schema/context"
    	xmlns:mvc="http://www.springframework.org/schema/mvc" xmlns:p="http://www.springframework.org/schema/p"
    	xmlns:tx="http://www.springframework.org/schema/tx"
    	xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
    		http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.3.xsd
    		http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.3.xsd
    		http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-4.3.xsd
    		http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.3.xsd">
    	<mvc:annotation-driven></mvc:annotation-driven>
    	<context:component-scan base-package="pers.*"></context:component-scan>
    	<context:annotation-config></context:annotation-config>
    	
    	
    	
    	<bean
    		class="org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter">
    		<property name="messageConverters">
    			<list>
    				
    				<ref bean="mappingJacksonHttpMessageConverter" />
    			</list>
    		</property>
    	</bean>
    	
    	
    	<bean id="mappingJacksonHttpMessageConverter"
    		class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter">
    		<property name="supportedMediaTypes">
    			<list>
    				<value>application/json;charset=UTF-8</value>
    			</list>
    		</property>
    	</bean>
    </beans>

![Center 9][]  
我的mybatis入门书中视图拦截器使用的是注释中的 AnnotationMethodHandlerAdapter，但根据注解 AnnotationMethodHandlerAdapter在3.2版本后已过时，现在支持使用RequestMappingHandlerAdapter，下图是两个类的属性图：

![Center 10][]![Center 11][]图放不下RequestMappingHandlerAdapter所有属性。  
可以看出AnnotationMethodHandlerAdapter中的大部分属性RequestMappingHandlerAdapter都有，且增加了不少属性，AnnotationMethodHandlerAdapter继承了WebContentGenerator，而RequestMappingHandlerAdapter继承了AbstractHandlerMethodAdapter，AbstractHandlerMethodAdapter继承了WebContentGenerator，由于我要设置的属性两者都有所以进行了替换，程序依然能正常允许。

index.jsp为空页面，网址后缀添加/role/getRole?id=xx  获取要查询的数据并以json格式下载，图如下：![Center 12][]

保存的json文件：

![Center 13][]  
Spring MVC使用json还需添加jackson-databind-x.x.x、jackson-annotations-x.x.x、jackson-core-x.x.x 3个jar包

我的数据库tb\_role就只有id，role\_name，note 3个属性，便于实践，就不讲太多

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