MyBatis with Spring: Could not find result map

Question

I cannot map the result of a query to a bean with MyBatis and Spring Boot using an xml file.

If I try to map the result with the annotation @ResultType(ResultBean.class) everything works, but I don't know how to map inner class, so I'm trying to map the result with the xml mapper.

I have this interface:

public interface MyMapper {
    @ResultMap("MyBean")
    @Select("SELECT myData as myData FROM myTable")
    public List<MyMapper> getMappedData();
}

And I have this MyMapper.xml file on the same package (the java class is in src/main/java/myPackage and the xml file is in /src/main/resources/myPackage).

<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">

<mapper namespace="myPackage.MyMapper">
    <resultMap id="MyBean" type="MyBean">
        <id property="myData " column="myData " />
    </resultMap>
</mapper>

This is the my SpringBootServletInitializer class:

@SpringBootApplication
@EnableTransactionManagement
@MapperScan("myPackage")
@PropertySource(value = "classpath:application.properties")
public class Application extends SpringBootServletInitializer {

    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }

    @Override
    protected SpringApplicationBuilder configure(SpringApplicationBuilder application) {
        return application.sources(Application.class);
    }

    @Value("${spring.datasource.jndi-name}")
    private String jndiName;

    @Bean
    public DataSource dataSource() {
        final JndiDataSourceLookup dsLookup = new JndiDataSourceLookup();
        DataSource dataSource = dsLookup.getDataSource(jndiName);
        return dataSource;
    }

    @Bean
    public DataSource jndiObjectFactoryBean() {
        JndiObjectFactoryBean jofb = new JndiObjectFactoryBean();
        jofb.setJndiName(jndiName);
        return (DataSource) jofb.getObject();
    }

    @Bean
    public DataSourceTransactionManager transactionManager(DataSource dataSource) {
        return new DataSourceTransactionManager(dataSource);
    }

    @Bean
    public ManagedTransactionFactory transactionFactory() {
        return new ManagedTransactionFactory();
    }

    @Bean
    public SqlSessionFactoryBean sqlSessionFactory(DataSource dataSource) throws Exception {
        SqlSessionFactoryBean sessionFactory = new SqlSessionFactoryBean();
        sessionFactory.setDataSource(dataSource);
        sessionFactory.setTypeAliasesPackage("beansPackage");
        return sessionFactory;
    }

    @Bean
    public SqlSessionFactory sqlSessionFactory() throws Exception {
      SqlSessionFactoryBean sqlSessionFactory = new SqlSessionFactoryBean();
      sqlSessionFactory.setDataSource(dataSource());
      return (SqlSessionFactory) sqlSessionFactory.getObject();
    }

}

The bean is

@Alias("MyBean")
public class MyBeanimplements Serializable {
    private static final long serialVersionUID = 3143220123058683967L;
    private String myData;
}

But it seems that MyBatis cannot find the xml mapper so it cannot map the result on the right bean. The error I receive is:

16:02:56,074 ERROR [org.springframework.boot.web.servlet.support.ErrorPageFilter] (default task-1) Forwarding to error page from request [/MyPage/getData] due to exception [Could not find result map myPackage.MyMapper.MyBean]: org.apache.ibatis.builder.IncompleteElementException: Could not find result map myPackage.MyMapper.MyBean

I'm missing some configuration? Maybe on the application.property file?

Answer 1

You have to put in < resultmap type the CanonicalName of the class

ex. MyBean pkg is: org.mypkg.MyBean:

 <resultMap id="MyBean" type="org.mypkg.MyBean">
    <id property="myData " column="myData " />
</resultMap>

Answer 2

Found the solution: I've used, for the xml mapper files, a dotted path (identical to the java mapper package name) but the path needs to be a normal path (with slashes and not dots).

Answer 3

1st thing is your bean class should have the getters and setters.

if you want to use an inner class as the bean, you have to use the $ sign to the path of your inner class like below.

<mapper namespace="myPackage.MyMapper">
    <resultMap id="MyBean" type="MainClass$MyBean">
        <id property="myData " column="myData " />
    </resultMap>
</mapper>

MainClassName$MyBean

public class MainClassName{
   
   public static class MyBean{
     private String myData;
     //getters
     //setters
   
   }
}

the reason is that Mybatits check your ben files after compiled. the MyBatis can't find a class file named MyBean.class . your class file name after compiling like this MainClassName$MyBean.class so we have to use the $ for that.