mybatis-plus的saveBatch报错，反而save没有问题？空指针Caused by: java.lang.NullPointerException

mybatis-plus中saveBatch等批量操作空指针问题

描述：
- 报错信息
- 解决思路
- 解决方案
- 疑问
- 参考的博客

描述：

又是马上要到了下班时间，哈哈，希望能给到你帮助，潦草解释一下

只要是批量的操作都会出现空指针，反而save单个操作却没有问题，你一定很懵，这是咋回事？

报错信息

Caused by: java.lang.NullPointerException: null
	at com.baomidou.mybatisplus.extension.toolkit.SqlHelper.sqlSessionBatch(SqlHelper.java:53) ~[mybatis-plus-extension-3.1.0.jar:3.1.0]
	at com.baomidou.mybatisplus.extension.service.impl.ServiceImpl.sqlSessionBatch(ServiceImpl.java:81) ~[mybatis-plus-extension-3.1.0.jar:3.1.0]
	at com.baomidou.mybatisplus.extension.service.impl.ServiceImpl.saveOrUpdateBatch(ServiceImpl.java:163) ~[mybatis-plus-extension-3.1.0.jar:3.1.0]
	at com.baomidou.mybatisplus.extension.service.IService.saveOrUpdateBatch(IService.java:76) ~[mybatis-plus-extension-3.1.0.jar:3.1.0]
	at com.baomidou.mybatisplus.extension.service.IService$$FastClassBySpringCGLIB$$f8525d18.invoke() ~[mybatis-plus-extension-3.1.0.jar:3.1.0]
	at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:218) ~[spring-core-5.1.5.RELEASE.jar:5.1.5.RELEASE]
	at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:749) ~[spring-aop-5.1.5.RELEASE.jar:5.1.5.RELEASE]
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:163) ~[spring-aop-5.1.5.RELEASE.jar:5.1.5.RELEASE]
	at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:294) ~[spring-tx-5.1.5.RELEASE.jar:5.1.5.RELEASE]
	at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:98) ~[spring-tx-5.1.5.RELEASE.jar:5.1.5.RELEASE]
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.1.5.RELEASE.jar:5.1.5.RELEASE]
	at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:688) ~[spring-aop-5.1.5.RELEASE.jar:5.1.5.RELEASE]
	at com.jx.cnhb.service.hiddenDanger.impl.YhEnterpriseInfoServiceImpl$$EnhancerBySpringCGLIB$$3ee24b2a.saveOrUpdateBatch() ~[classes/:na]

解决思路

起初是怀疑bean没有注入

突然发现bean是已经注入的了，可以获取到baseMapper，然后就又单独试了试save等方法，发现完全没有问题

于是，就根据源码，一步一步找原因

在这里插入图片描述

功夫不负有心人啊，原因找到了，sqlsession工厂为null，所以报空指针

解决方案

既然知道了问题所在，那就对症下药，

然后全局搜索SqlSessionFactory

果不其然，找到了

原来是多数据源的配置问题

@Configuration
//指定mapper存放目录，并改包下的mapper使用本datasource
@MapperScan(basePackages = {"com.jx.cnhb.mapper", "com.jx.cnhb.hiddenDanger"},sqlSessionTemplateRef = "damengSqlSessionTemplate")
public class DMConfiguration {
    @Bean(name = "damengDataSource")
    //多数据源必需
    @Primary
    public DataSource setDataSource(DMConfig dmConfig){
        DruidDataSource dds = new DruidDataSource();
        dds.setUrl(dmConfig.getUrl());
        dds.setDriverClassName(dmConfig.getDriverClassName());
        dds.setUsername(dmConfig.getUsername());
        dds.setPassword(dmConfig.getPassword());
        return dds;
    }

    @Bean(name = "damengSqlSessionFactory")
    @Primary
    public SqlSessionFactory setSqlSessionFactory(@Qualifier("damengDataSource") DataSource dataSource) throws Exception{
        SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean();
        sqlSessionFactoryBean.setDataSource(dataSource);
//        sqlSessionFactoryBean.setMapperLocations(new PathMatchingResourcePatternResolver().getResources("classpath*:com/jx/cnhb/mapper/*.xml"));
        MybatisConfiguration configuration = new MybatisConfiguration();
        configuration.setDefaultScriptingLanguage(MybatisXMLLanguageDriver.class);
        configuration.setJdbcTypeForNull(JdbcType.NULL);
        sqlSessionFactoryBean.setConfiguration(configuration);
        return sqlSessionFactoryBean.getObject();
    }
    @Bean(name = "damengSqlSessionTemplate")
    @Primary
    public SqlSessionTemplate setSqlSessionTemplate(@Qualifier("damengSqlSessionFactory")SqlSessionFactory sqlSessionFactory){
        return new SqlSessionTemplate(sqlSessionFactory);
    }

}

上文截图到了报错原因

在这里插入图片描述

发现并没有配置这个mybatis的全局配置

在这里插入图片描述

且发现数据都是默认的

然后去百度多数据源的配置，发现此处原来少配置了个GlobalConfig的bean，所以才会出现获取不到当前类的sqlsession工厂

修改后配置文件为

@Configuration
//指定mapper存放目录，并改包下的mapper使用本datasource
@MapperScan(basePackages = {"com.jx.cnhb.mapper", "com.jx.cnhb.hiddenDanger"},sqlSessionTemplateRef = "damengSqlSessionTemplate")
public class DMConfiguration {
    @Bean(name = "damengDataSource")
    //多数据源必需
    @Primary
    public DataSource setDataSource(DMConfig dmConfig){
        DruidDataSource dds = new DruidDataSource();
        dds.setUrl(dmConfig.getUrl());
        dds.setDriverClassName(dmConfig.getDriverClassName());
        dds.setUsername(dmConfig.getUsername());
        dds.setPassword(dmConfig.getPassword());
        return dds;
    }

    @Bean(name = "damengSqlSessionFactory")
    @Primary
    public SqlSessionFactory setSqlSessionFactory(@Qualifier("damengDataSource") DataSource dataSource) throws Exception{
        MybatisSqlSessionFactoryBean sqlSessionFactoryBean = new MybatisSqlSessionFactoryBean();
        sqlSessionFactoryBean.setDataSource(dataSource);
        sqlSessionFactoryBean.setGlobalConfig(globalConfig());
        MybatisConfiguration configuration = new MybatisConfiguration();
        configuration.setDefaultScriptingLanguage(MybatisXMLLanguageDriver.class);
        configuration.setJdbcTypeForNull(JdbcType.NULL);
        sqlSessionFactoryBean.setConfiguration(configuration);
        return sqlSessionFactoryBean.getObject();
    }
    @Bean(name = "damengSqlSessionTemplate")
    @Primary
    public SqlSessionTemplate setSqlSessionTemplate(@Qualifier("damengSqlSessionFactory")SqlSessionFactory sqlSessionFactory){
        return new SqlSessionTemplate(sqlSessionFactory);
    }

    @Bean("globalConfig")
    public GlobalConfig globalConfig(){
        // 此处也可配置元对象字段填充控制器
        return new GlobalConfig();
    }

}

问题得以解决，可以看出来已经获取到工厂了

在这里插入图片描述