spring 使用通用Mapper批量添加数据 java.lang.InstantiationException: tk.mybatis.mapper.provide.SpecialProvider

转载:https://www.cnblogs.com/yql1986/p/9459478.html

通用Mapper是一款针对mybatis进行扩展的轻量级组件,使用起来非常方便。当调用其针对mysql进行批量添加数据的方法时,发现报错,仔细研究了一番,发现是在使用通用Mapper上出现了问题。下面贴出本文使用的通用的Mapper github 地址及其版本。

通用Mapper github主页:https://github.com/abel533/Mapper/ 本文示例使用的版本是3.5.4-SNAPSHOT 该分支的链接: https://github.com/abel533/Mapper/tree/3.5.x

继承通用Mapper的DAO层示例代码:

package com.github.torlight.sbex;

import tk.mybatis.mapper.common.Mapper;
import tk.mybatis.mapper.common.MySqlMapper;

public interface TEntityDAO extends Mapper<TEntityDO>,MySqlMapper<TEntityDO>{
    
}

批量添加数据的示例代码:

package com.github.torlight.sbex;

import java.util.ArrayList;
import java.util.List;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.ApplicationContext;

@SpringBootApplication
public class Example3Main {

    public static void main(String[] args) {
        
        ApplicationContext ctx=SpringApplication.run(Example3Main.class, args);
        
        System.out.println("Example3Main running...");
        
        List<TEntityDO> tEntityDOList=new ArrayList<TEntityDO>(10);
        tEntityDOList.add(new TEntityDO("1"));
        tEntityDOList.add(new TEntityDO("2"));
        tEntityDOList.add(new TEntityDO("3"));
        tEntityDOList.add(new TEntityDO("4"));
        tEntityDOList.add(new TEntityDO("5"));
        tEntityDOList.add(new TEntityDO("6"));
        tEntityDOList.add(new TEntityDO("7"));
        tEntityDOList.add(new TEntityDO("8"));
        tEntityDOList.add(new TEntityDO("9"));
        tEntityDOList.add(new TEntityDO("10"));
        
        TEntityDAO tEntityDAO=ctx.getBean(TEntityDAO.class);
        tEntityDAO.insertList(tEntityDOList);
            
    }

}

运行程序后,出现如下错误:

Exception in thread "main" org.mybatis.spring.MyBatisSystemException: nested exception is org.apache.ibatis.builder.BuilderException: Error invoking SqlProvider method (tk.mybatis.mapper.provider.SpecialProvider.dynamicSQL).  Cause: java.lang.InstantiationException: tk.mybatis.mapper.provider.SpecialProvider
    at org.mybatis.spring.MyBatisExceptionTranslator.translateExceptionIfPossible(MyBatisExceptionTranslator.java:77)
    at org.mybatis.spring.SqlSessionTemplate$SqlSessionInterceptor.invoke(SqlSessionTemplate.java:446)
    at com.sun.proxy.$Proxy62.insert(Unknown Source)
    at org.mybatis.spring.SqlSessionTemplate.insert(SqlSessionTemplate.java:278)
    at org.apache.ibatis.binding.MapperMethod.execute(MapperMethod.java:57)
    at org.apache.ibatis.binding.MapperProxy.invoke(MapperProxy.java:59)
    at com.sun.proxy.$Proxy63.insertList(Unknown Source)
    at com.github.torlight.sbex.Example3Main.main(Example3Main.java:33)
Caused by: org.apache.ibatis.builder.BuilderException: Error invoking SqlProvider method (tk.mybatis.mapper.provider.SpecialProvider.dynamicSQL).  Cause: java.lang.InstantiationException: tk.mybatis.mapper.provider.SpecialProvider
    at org.apache.ibatis.builder.annotation.ProviderSqlSource.createSqlSource(ProviderSqlSource.java:103)
    at org.apache.ibatis.builder.annotation.ProviderSqlSource.getBoundSql(ProviderSqlSource.java:73)
    at org.apache.ibatis.mapping.MappedStatement.getBoundSql(MappedStatement.java:292)
    at org.apache.ibatis.executor.statement.BaseStatementHandler.<init>(BaseStatementHandler.java:64)
    at org.apache.ibatis.executor.statement.PreparedStatementHandler.<init>(PreparedStatementHandler.java:40)
    at org.apache.ibatis.executor.statement.RoutingStatementHandler.<init>(RoutingStatementHandler.java:46)
    at org.apache.ibatis.session.Configuration.newStatementHandler(Configuration.java:545)
    at org.apache.ibatis.executor.SimpleExecutor.doUpdate(SimpleExecutor.java:48)
    at org.apache.ibatis.executor.BaseExecutor.update(BaseExecutor.java:117)
    at org.apache.ibatis.executor.CachingExecutor.update(CachingExecutor.java:76)
    at org.apache.ibatis.session.defaults.DefaultSqlSession.update(DefaultSqlSession.java:198)
    at org.apache.ibatis.session.defaults.DefaultSqlSession.insert(DefaultSqlSession.java:185)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at org.mybatis.spring.SqlSessionTemplate$SqlSessionInterceptor.invoke(SqlSessionTemplate.java:433)
    ... 6 more
Caused by: java.lang.InstantiationException: tk.mybatis.mapper.provider.SpecialProvider
    at java.lang.Class.newInstance(Class.java:364)
    at org.apache.ibatis.builder.annotation.ProviderSqlSource.createSqlSource(ProviderSqlSource.java:85)
    ... 22 more

当出现该错误之后,随手在网上搜索了一把,看看别人是怎么解决的。找到如下一篇文章(文章的链接如下文),非常遗憾该文章也没有给出更加实际的解决办法。

tk.mybatis.mapper.provider.SpecialProvider.<init>() 原文链接地址:https://www.cnblogs.com/softidea/p/6624766.html

我把目光停留在了用于访问数据库的DAO层 TEntityDAO 类上面,该接口继承了Mapper和MySqlMapper 两个接口,这两个接口有啥区别呢? 带着这个疑问,我进入到这两个接口。细看了两个接口之后,发现Mapper只是提供普通的CRUD,而批量添加数据接口在后者。两者区别在这儿。下面贴出这两个接口的截图。


通用Mapper接口

批量添加接口

看到这两个接口的区别,回想到通用Mpper配置,配置扫描时时只添加了通用Mapper接口,tk.mybatis.mapper.common.Mapper ,是不是也要把批量添加的接口也要添加到接口扫描配置里面。

通用接口扫描代码:

@Bean
public MapperScannerConfigurer mapperScannerConfigurer(){
    
    Properties properties=new Properties();
    properties.put("mappers","tk.mybatis.mapper.common.Mapper");

    MapperScannerConfigurer msc=new MapperScannerConfigurer();      
    msc.getMapperHelper().setProperties(properties);
    msc.setBasePackage(DataSourceConfig.PACKAGE);
    msc.setSqlSessionFactoryBeanName(DataSourceConfig.SESSION_FACTORY_BEAN_NAME);
    
    return msc;
}

修改后的通用接口扫描代码:

@Bean
public MapperScannerConfigurer mapperScannerConfigurer(){
    
    Properties properties=new Properties();
    properties.put("mappers","tk.mybatis.mapper.common.Mapper,tk.mybatis.mapper.common.MySqlMapper");

    MapperScannerConfigurer msc=new MapperScannerConfigurer();      
    msc.getMapperHelper().setProperties(properties);
    msc.setBasePackage(DataSourceConfig.PACKAGE);
    msc.setSqlSessionFactoryBeanName(DataSourceConfig.SESSION_FACTORY_BEAN_NAME);
    
    return msc;
}

重新运行程序后,还真是这儿的原因。

总结:通用Mapper基本的CRUD方法和批量操作数据库的方法不是放在一起,需要由程序按需加载。
示例代码已经上传到github,代码中没有数据库相关的配置,运行代码之前,需要把数据库相关的配置补上。
完整的代码见:https://github.com/gittorlight/springboot-example/tree/master/example3

以上是该博主解决springboot中整合mybatis的解决方法,再springmvc中使用xml配置的,如下

<bean class="tk.mybatis.spring.mapper.MapperScannerConfigurer">
    <property name="basePackage" value="com.sf.argus.web.mapper"/>
    <property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"/>
</bean>

再MapperScannerConfigurer中有这样的代码

this.mapperHelper.ifEmptyRegisterDefaultInterface();

再点进去是这样的

/**
 * 如果当前注册的接口为空,自动注册默认接口
 */
public void ifEmptyRegisterDefaultInterface() {
    if (registerClass.size() == 0) {
        registerMapper("tk.mybatis.mapper.common.Mapper");
    }
}

确实只注册了一个

所以,我们要自己指定注册的mapper,改下xml加入属性,如下

<bean class="tk.mybatis.spring.mapper.MapperScannerConfigurer">
    <property name="basePackage" value="com.sf.argus.web.mapper"/>
    <property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"/>
    <property name="properties">
        <value>
            mappers=tk.mybatis.mapper.common.Mapper,tk.mybatis.mapper.common.MySqlMapper
        </value>
    </property>
</bean>

再试试就ok了!!!