解决tk.mybatis中写自定义的mapper的问题
作者：伟大的格尔夫斯
这篇文章主要介绍了使用tk.mybatis中写自定义的mapper的问题，具有很好的参考价值，希望对大家有所帮助。如有错误或未考虑完全的地方，望不吝赐教
问题
使用tk.mybatis能满足大多数操作，但是想添加自己的查询方法时候今天遇到了坑，总结一下
大致分两种
1. 使用纯接口注解方式时
在mapper接口中自定义方法上添加如@Select，@insert类似的注释，里边写相应的sql语句，如下
import org.apache.ibatis.annotations.Select;
import tk.mybatis.mapper.common.Mapper;
public interface CountryMapper extends Mapper<Country> {
@Select("select * from country where countryname = #{countryname}")
Country selectByCountryName(String countryname);
}
这种方式没有问题
2. 如果使用 XML 方式，需要提供接口对应的 XML 文件
例如提供了 CountryMapper.xml 文件，内容如下：
<!DOCTYPE mapper
PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="tk.mybatis.sample.mapper.CountryMapper">
<select id="selectByCountryName" resultType="tk.mybatis.model.Country">
select * from country where countryname = #{countryname}
</select>
</mapper>
这里会有点问题
注意： resultType 如果映射的是个实体类最好写 包的全路径名 如tk.mybatis.model.Country 如果写 Country会报错，导致项目无法启动。
tk mapper 通用mapper的bug
<bean class="tk.mybatis.spring.mapper.MapperScannerConfigurer">
<property name="basePackage" value="com.isea533.mybatis.mapper"/>
<property name="properties">
<value>
mappers=tk.mybatis.mapper.common.Mapper
</value>
</property>
</bean>
basePackage的属性值 不能包含通用mapper所在的包
Error starting ApplicationContext. To display the auto-configuration report re-run your application with 'debug' enabled.
2018-03-14 12:39:21.741 ERROR [main] [hio-sys] o.s.boot.SpringApplication - Application startup failed
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'tk.mybatis.mapper.autoconfigure.MapperAutoConfiguration': Invocation of init method failed; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'baseMapper' defined in file []: Invocation of init method failed; nested exception is tk.mybatis.mapper.MapperException: tk.mybatis.mapper.MapperException: java.lang.ClassCastException: sun.reflect.generics.reflectiveObjects.TypeVariableImpl cannot be cast to java.lang.Class
at org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor.postProcessBeforeInitialization(InitDestroyAnnotationBeanPostProcessor.java:137)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyBeanPostProcessorsBeforeInitialization(AbstractAutowireCapableBeanFactory.java:409)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1620)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:555)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:483)
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:761)
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:867)
at org.springframework.context.support.AbstractApplicationContext.__refresh(AbstractApplicationContext.java:543)
at org.springframework.context.support.AbstractApplicationContext.jrLockAndRefresh(AbstractApplicationContext.java)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java)
at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.refresh(EmbeddedWebApplicationContext.java:122)
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:693)
at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:360)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:303)
at com.jzy.hio.HioSysApplication.main(HioSysApplication.java:35)
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'baseMapper' defined in file [C:\Users\coffee\OneDrive\workspace\v2r1-hio-base\target\classes\com\jzy\hio\base\mapper\BaseMapper.class]: Invocation of init method failed; nested exception is tk.mybatis.mapper.MapperException: tk.mybatis.mapper.MapperException: java.lang.ClassCastException: sun.reflect.generics.reflectiveObjects.TypeVariableImpl cannot be cast to java.lang.Class
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1628)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:555)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:483)
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.getBeansOfType_jrOrig(DefaultListableBeanFactory.java:519)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.getBeansOfType(DefaultListableBeanFactory.java)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.getBeansOfType_jrOrig(DefaultListableBeanFactory.java:508)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.getBeansOfType(DefaultListableBeanFactory.java)
at org.springframework.context.support.AbstractApplicationContext.getBeansOfType(AbstractApplicationContext.java:1188)
at tk.mybatis.mapper.autoconfigure.MapperAutoConfiguration.addPageInterceptor(MapperAutoConfiguration.java:71)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.__invoke(DelegatingMethodAccessorImpl.java:43)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor$LifecycleElement.invoke(InitDestroyAnnotationBeanPostProcessor.java:366)
at org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor$LifecycleMetadata.invokeInitMethods(InitDestroyAnnotationBeanPostProcessor.java:311)
at org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor.postProcessBeforeInitialization(InitDestroyAnnotationBeanPostProcessor.java:134)
... 18 common frames omitted
Caused by: tk.mybatis.mapper.MapperException: tk.mybatis.mapper.MapperException: java.lang.ClassCastException: sun.reflect.generics.reflectiveObjects.TypeVariableImpl cannot be cast to java.lang.Class
at tk.mybatis.mapper.mapperhelper.MapperHelper.setSqlSource(MapperHelper.java:248)
at tk.mybatis.mapper.mapperhelper.MapperHelper.processConfiguration(MapperHelper.java:311)
at tk.mybatis.spring.mapper.MapperFactoryBean.checkDaoConfig(MapperFactoryBean.java:54)
at org.springframework.dao.support.DaoSupport.afterPropertiesSet(DaoSupport.java:44)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1687)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1624)
... 39 common frames omitted
Caused by: tk.mybatis.mapper.MapperException: java.lang.ClassCastException: sun.reflect.generics.reflectiveObjects.TypeVariableImpl cannot be cast to java.lang.Class
at tk.mybatis.mapper.mapperhelper.MapperTemplate.setSqlSource(MapperTemplate.java:258)
at tk.mybatis.mapper.mapperhelper.MapperHelper.setSqlSource(MapperHelper.java:245)
... 44 common frames omitted
Caused by: java.lang.ClassCastException: sun.reflect.generics.reflectiveObjects.TypeVariableImpl cannot be cast to java.lang.Class
at tk.mybatis.mapper.mapperhelper.MapperTemplate.getEntityClass(MapperTemplate.java:290)
at tk.mybatis.mapper.provider.base.BaseSelectProvider.selectOne(BaseSelectProvider.java:50)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.__invoke(DelegatingMethodAccessorImpl.java:43)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java)
at java.lang.reflect.Method.invoke(Method.java:498)
at tk.mybatis.mapper.mapperhelper.MapperTemplate.setSqlSource(MapperTemplate.java:246)
... 45 common frames omitted
以上为个人经验，希望能给大家一个参考，也希望大家多多支持脚本之家。