在学习Spring完之后简单的了解了MyBatis。然后进行简单的整合,遇到MyBatista接口映射的Bean无法自动注入的问题;
代码异常:
线程“main”org.springframe .bean .factory中的异常。创建名为“UserController”的bean时出错:通过字段“userdao”表示的不满足的依赖关系;嵌套异常是org.springframe .bean .factory。BeanCreationException:在文件[C:\Users\li rui long\eclipse-workspace\MyBatis_Demo\build\classes\com\mybatis\dao\ userdao]中创建名为“userdao”的bean时出错。类]:在设置bean属性“sqlSessionFactory”时无法解析对bean“sqlSessionFactory”的引用;嵌套异常是org.springframe .bean .factory。BeanCreationException:在类路径资源[ApplicationContext]中定义名称为“sqlSessionFactory”的bean创建错误。:设置bean属性“dataSource”时不能解析对bean“dataSource”的引用;嵌套异常是org.springframe .bean .factory。BeanCreationException:创建名为“dataSource”的bean时出错:查找方法解析失败;嵌套异常是java.lang。IllegalStateException:未能从ClassLoader [jdk.internal.loader.ClassLoader . [email protected]]内检类[org.apache.commons.dbcp2.BasicDataSource]
异常提示,控制器层的Bean无法创建,原因是MyBatis对应的映射接口无法完成映射,无法生成DAO层的Bean;
所以问题应该出现在XML文件里,
测试类,13行报错:
1 package com.mybatis.test; 2 3 import org.springframework.context.ApplicationContext; 4 import org.springframework.context.support.ClassPathXmlApplicationContext; 5 6 import com.mybatis.controller.UserController; 7 8 9 public class Test_Controller { 10 11 public static void main(String[] args) { 12 // TODO Auto-generated method stub 13 ApplicationContext app = new ClassPathXmlApplicationContext("ApplicationContext.xml"); 14 UserController coll = (UserController) app.getBean("UserController"); 15 coll.test(); 16 } 17 18 }
对ApplicationContext.xml配置文件进行一步步排查:
<?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: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/context http://www.springframework.org/schema/context/spring-context.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd"> <!-- 指定需要扫描的包,使注解生效 --> <context:component-scan base-package="com.mybatis.po"/> <context:component-scan base-package="com.mybatis.dao"/> <context:component-scan base-package="com.mybatis.Controller"/> <!-- 配置数据源 --> <bean id="dataSource" class="org.apache.commons.dbcp2.BasicDataSource" destroy-method="close"> <property name="driverClassName" value = "com.mysql.jdbc.Driver"/> <property name="url" value ="jdbc:mysql://localhost:3306/Springtest?characterEncoding=utf8"/> <property name="username" value = "root"/> <property name="password" value ="mysql" /> <!-- 可同时连接的最大的连接数 --> <property name="maxActive" value="60" /> <!-- 最大的空闲的连接数 --> <property name="maxTotal" value="60" /> <!-- 最小的空闲的连接数,低于这个数量会被创建新的连接,默认为0 --> <property name="maxIdle" value="5" /> <!-- 连接池启动时创建的初始化连接数量,默认值为0 --> <property name="initialSize" value="5" /> </bean> <!-- 添加事务支持 --> <bean id = "txManager" class = "org.springframework.jdbc.datasource.DataSourceTransactionManager"> <property name = "dataSource" ref = "dataSource"/> </bean> <!-- 开启事务注解 --> <tx:annotation-driven transaction-manager ="txManager"/> <!-- 配置Mybatis工厂,同时指定数据源,并与MyBatista完美结合 --> <bean id="sqlSessionFactory" class = "org.mybatis.spring.SqlSessionFactoryBean"> <property name="dataSource" ref ="dataSource"/> <!-- configLocation 的属性为Mybatis 的核心配置文件 --> <property name = "configLocation" value = "classpath:mybatis-config.xml"></property> </bean> <!-- Mapper 代理开发,使用Spring自动扫描MyBatista的接口并装配 --> <!-- Spring 将指定包中所有的被@Mapper注解标注的接口自动装配为MyBatatis的映射接口 --> <bean class = "org.mybatis.spring.mapper.MapperScannerConfigurer"> <!-- MyBatis-spring组件的扫描器 --> <property name="basePackage" value = "com.mybatis.dao"/> <property name="sqlSessionFactoryBeanName" value = "sqlSessionFactory"/> </bean> </beans>
- 检查扫描的包名,是否有写错或者少写的。
- 确定数据源的配置正常,我的问题就出在这里,修改数据库配置信息(密码等),看是否会报不一样的错,当还是原来的错,说明配置文件没有加载或者数据源错误。我用的DBCP数据源(需要导入两个包DBCP+连接池包),修改密码后还是报同样的错误所以我尝试着用Spring自带的数据源,解决了问题,正确代码:
1 <?xml version="1.0" encoding="UTF-8"?> 2 <beans xmlns="http://www.springframework.org/schema/beans" 3 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 4 xmlns:context="http://www.springframework.org/schema/context" 5 xmlns:tx="http://www.springframework.org/schema/tx" 6 xsi:schemaLocation=" 7 http://www.springframework.org/schema/beans 8 http://www.springframework.org/schema/beans/spring-beans.xsd 9 http://www.springframework.org/schema/context 10 http://www.springframework.org/schema/context/spring-context.xsd 11 http://www.springframework.org/schema/tx 12 http://www.springframework.org/schema/tx/spring-tx.xsd"> 13 <!-- 指定需要扫描的包,使注解生效 --> 14 15 <context:component-scan base-package="com.mybatis.po"/> 16 <context:component-scan base-package="com.mybatis.dao"/> 17 <context:component-scan base-package="com.mybatis.Controller"/> 18 <!-- 配置数据源 --> 19 <bean id = "dataSource" class = "org.springframework.jdbc.datasource.DriverManagerDataSource"> 20 <property name="driverClassName" value = "com.mysql.jdbc.Driver"/> 21 <property name="url" value ="jdbc:mysql://localhost:3306/Springtest?characterEncoding=utf8"/> 22 <property name="username" value = "root"/> 23 <property name="password" value ="mysql" /> 24 </bean> 25 26 <!-- 添加事务支持 --> 27 <bean id = "txManager" class = "org.springframework.jdbc.datasource.DataSourceTransactionManager"> 28 <property name = "dataSource" ref = "dataSource"/> 29 </bean> 30 <!-- 开启事务注解 --> 31 <tx:annotation-driven transaction-manager ="txManager"/> 32 <!-- 配置Mybatis工厂,同时指定数据源,并与MyBatista完美结合 --> 33 <bean id="sqlSessionFactory" class = "org.mybatis.spring.SqlSessionFactoryBean"> 34 <property name="dataSource" ref ="dataSource"/> 35 <!-- configLocation 的属性为Mybatis 的核心配置文件 --> 36 <property name = "configLocation" value = "classpath:mybatis-config.xml"></property> 37 </bean> 38 <!-- Mapper 代理开发,使用Spring自动扫描MyBatista的接口并装配 --> 39 <!-- Spring 将指定包中所有的被@Mapper注解标注的接口自动装配为MyBatatis的映射接口 --> 40 <bean class = "org.mybatis.spring.mapper.MapperScannerConfigurer"> 41 <!-- MyBatis-spring组件的扫描器 --> 42 <property name="basePackage" value = "com.mybatis.dao"/> 43 <property name="sqlSessionFactoryBeanName" value = "sqlSessionFactory"/> 44 </bean> 45 46 </beans>
- 检查对应的依赖类,配置文件路径能否Ctrl进去。MyBatis的核心文件和映射文件路径是否正确。以下是我的代码:
-
<?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> <mappers> <!-- 映射文件--> <mapper resource = "com/mybatis/dao/UserMapper.xml"/> </mappers> </configuration
-
<?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.mybatis.dao.UserDao"> <!-- 根据ID查询用户信息 --> <select id="selectUserById" parameterType = "Integer" resultType = "com.mybatis.po.Myuser"> SELECT * FROM user WHERE uid = #{uid} </select> <!-- <select id="selectAllUser" resultType = "com.mybatis.po.Myuser"> SELECT * FROM user </select> 添加一个用户,#{uname}为com.mybatis.po.MyUser属性值 <insert id ="addUser" parameterType = "com.mybatis.po.Myuser"> INSERT INTO user (uname,usex) VALUES (#{uname},#{usex}) </insert> 修改一个用户 <update id="updateUser" parameterType = "com.mybatis.po.Myuser"> UPDATE user SET uname = #{unmae},usex = #{user} where uid = #{uid} </update> 删除一个用户 <delete id = "delectUser" parameterType = "Integer"> DELECT from user WHERE uid = #{uid} </delete> --> </mapper >
看Dao层的接口和Mapped的映射文件是否是在同一包下。
类似问题的博客:
https://blog.csdn.net/h363659487/article/details/74275972
https://blog.csdn.net/u012385190/article/details/53186552
嗯嗯,第一次写这样的博客,希望会对大家有帮助!!,愿我们都被温柔以待!2019.4.21。
原文地址:https://www.cnblogs.com/liruilong/p/10744962.html