Spring-Java配置@Bean参数

Question

I've just updated from Spring 3.1.1 to 3.2.6

With 3.1 the following code worked well:

@Bean(name = DEMO_DS)
public JndiObjectFactoryBean demoDataSource()
{
    JndiObjectFactoryBean factory = new JndiObjectFactoryBean();
    factory.setJndiName(JDBC_DEMO_DS);
    factory.setProxyInterface(DataSource.class);
    return factory;
}

@Bean(name = DEMO_SESSION_FACTORY)
public SqlSessionFactoryBean demoSqlSessionFactory(@Qualifier(DEMO_DS) DataSource dataSource)
{
    SqlSessionFactoryBean sessionFactory = new SqlSessionFactoryBean();
    sessionFactory.setDataSource(dataSource);
    sessionFactory.setConfigLocation(new ClassPathResource("demo/config.xml"));

    return sessionFactory;
}

However with the uprgraded version I get the following exception:

Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [javax.sql.DataSource] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {@org.springframework.beans.factory.annotation.Qualifier(value=DemoDataSource)}

I have multiple DataSources hence the @Qualifier is a need.

Thanks.

Edit:

It seems that this solves the problem:

public DataSource dataSourceFactory() {
    try
    {
        return (DataSource) demoDataSource().getObject();
    }
    catch (Exception ex)
    {
        throw new RuntimeException(ex);
    }
}

...

sessionFactory.setDataSource(dataSourceFactory());

However I don't think it's a nice solution.

Answer 1

Depending on your need rewrite your configuration a little. If you don't really need the datasource injected you can do something like this.

@Bean(name = DEMO_DS)
public JndiObjectFactoryBean demoDataSource() {
    JndiObjectFactoryBean factory = new JndiObjectFactoryBean();
    factory.setJndiName(JDBC_DEMO_DS);
    factory.setProxyInterface(DataSource.class);
    return factory;
}

@Bean(name = DEMO_SESSION_FACTORY)
public SqlSessionFactoryBean demoSqlSessionFactory() {
    SqlSessionFactoryBean sessionFactory = new SqlSessionFactoryBean();
    sessionFactory.setDataSource(demoDataSource().getObject());
    sessionFactory.setConfigLocation(new ClassPathResource("demo/config.xml"));
    return sessionFactory;
}

If you need to have a datasource injected you might want to switch to using a JndiLocatorDelegate to do the lookup instead of a JndiObjectFactoryBean .

@Bean(name = DEMO_DS)
public DataSource demoDataSource() throws NamingException {
    return JndiLocatorDelegate.createDefaultResourceRefLocator().lookup(JDBC_DEMO_DS, DataSource.class);
}

This gives you a DataSource directly instead of a FactoryBean<Object> (which is what the JndiObjctFactoryBean is) what probably is the source of the problem.

Or (in theory) you should also be able to use a @Value annotation on a property in your config class. Instead of a @Value a normal @Resource should also do the trick (that can also delegate a call to JNDI for a lookup).

public class MyConfig {

    @Value("${" + JDBC_DEMO_DS + "}")
    private DataSource demoDs;

}

With @Resource

public class MyConfig {

    @Resource(mappedName=JDBC_DEMO_DS)
    private DataSource demoDs;

}

And you can then simply reference it in your configuration method.

@Bean(name = DEMO_SESSION_FACTORY)
public SqlSessionFactoryBean demoSqlSessionFactory() {
    SqlSessionFactoryBean sessionFactory = new SqlSessionFactoryBean();
    sessionFactory.setDataSource(demoDs);
    sessionFactory.setConfigLocation(new ClassPathResource("demo/config.xml"));
    return sessionFactory;
}