我想使用@Configuration批注来连接我的应用程序,但我一直在初始化程序之一中收到NullPointerException,因为它引用的bean尚未初始化(我认为)。我已经尝试在web.xml中指定“root”配置类,并尝试进行包扫描,但都没有成功。如何确保依赖配置使用Spring @Configuration注释初始化?
对不起,大代码转储。 我试图产生一个更简单的类来重现问题,但当然,当我这样做时,一切正常。这里是我的课(进口消隐):
DataSourceConfig.java:
@Configuration
public class DataSourceConfig {
public DataSourceConfig() {
System.err.println("DataSourceConfig constructed...");
}
@Bean
public DataSource dataSource() {
BasicDataSource bean = new BasicDataSource();
bean.setDriverClassName("com.mysql.jdbc.Driver");
bean.setUrl("jdbc:mysql://localhost:3306/observation");
bean.setUsername("observation");
bean.setPassword("*******");
bean.setInitialSize(1);
bean.setMaxActive(5);
bean.setTestOnBorrow(true);
System.err.println("dataSource bean initialized: " + bean.toString());
return bean;
}
}
HibernateConfig.java
@Configuration
@Import(DataSourceConfig.class)
public class HibernateConfig {
public HibernateConfig() {
System.err.println("HibernateConfig constructing...");
}
@Autowired
private DataSourceConfig dataSourceConfig;
@Bean
protected NamingStrategy namingStrategy() {
return new ImprovedNamingStrategy();
}
private AnnotationSessionFactoryBean sessionFactoryBean = null;
@Bean
@DependsOn("dataSourceConfig")
public AnnotationSessionFactoryBean sessionFactory() {
if (sessionFactoryBean == null) {
sessionFactoryBean = new AnnotationSessionFactoryBean();
NPE Here--> sessionFactoryBean.setDataSource(dataSourceConfig.dataSource());
sessionFactoryBean.setSchemaUpdate(true);
sessionFactoryBean.setNamingStrategy(namingStrategy());
sessionFactoryBean.setPackagesToScan(new String[] {
"com.newco.observations.domain",
"com.newco.observations.domain.*" });
Properties props = new Properties();
props.setProperty("hibernate.default_schema", "observation");
props.setProperty("hibernate.dialect",
"org.hibernate.dialect.MySQLDialect");
props.setProperty("hibernate.show_sql", "true");
sessionFactoryBean.setHibernateProperties(props);
System.err.println("sessionFactory initialized");
}
return sessionFactoryBean;
}
@Bean
@DependsOn("dataSourceConfig")
public JdbcTemplate jdbcTemplate() {
return new JdbcTemplate(dataSourceConfig.dataSource());
}
@Bean
@DependsOn("sessionFactory")
public ResourceTransactionManager txManager() {
HibernateTransactionManager bean = new HibernateTransactionManager();
bean.setSessionFactory((SessionFactory) sessionFactory().getObject());
return bean;
}
@Bean
@DependsOn("sessionFactory")
public HibernateTemplate hibernateTemplate() {
return new HibernateTemplate((SessionFactory) sessionFactory()
.getObject());
}
}
DaoConfig.java:
@Configuration
@Import(HibernateConfig.class)
public class DaoConfig {
public DaoConfig()
{
System.err.println("DaoConfig constructing...");
}
private @Autowired HibernateConfig hibernateConfig;
@Bean
@DependsOn("hibernateTemplate")
public PhenomenonGroupDao phenomenonGroupDao()
{
PhenomenonGroupDaoImpl bean = new PhenomenonGroupDaoImpl();
bean.setHibernateTemplate(hibernateConfig.hibernateTemplate());
return bean;
}
@Bean
@DependsOn("hibernateTemplate")
public PhenomenonDao phenomenonDao()
{
PhenomenonDaoImpl bean = new PhenomenonDaoImpl();
bean.setHibernateTemplate(hibernateConfig.hibernateTemplate());
return bean;
}
@Bean
@DependsOn("hibernateTemplate")
public DiscretePhenomenonDao discretePhenomenonDao()
{
DiscretePhenomenonDaoImpl bean = new DiscretePhenomenonDaoImpl();
bean.setHibernateTemplate(hibernateConfig.hibernateTemplate());
return bean;
}
}
您可以看到System.err.println和@DependsOn注解是一种扯淡我正在做的帽子。
我可以提供完整的日志,如果它是有用的,但这里是我认为是相关线(一点点的格式,以使其更具可读性(也许)):
- 208 [线程0 ] INFO org.springframework.context.annotation.ConfigurationClassEnhancer
- 成功增强com.bjk.observation.server.config.DaoConfig;增强的类名称为:com.bjk.observation.server.config.DaoConfig $$ EnhancerByCGLIB $$ 96e1956
- 229 [线程0] INFO org.springframework.beans.factory.support.DefaultListableBeanFactory
- 预实例单身in org.s[email protected]185572a:定义bean [org.springframework.context.annotation.internalConfigurationAnnotationProcessor,org.springframework.context.annotation.internalAutowiredAnnotationProcessor,org.springframework.context.annotation.internalRequiredAnnotationProcessor,org。 springframework.context.annotation.internalCommonAnnotationProcessor,org.springframework.context.annotation.internalPersistenceAnnotationProcessor,daoConfig,com.bjk.observation.server.config.DataSourceConfig#0,dataSource,com.bjk.observation.server.config.HibernateConfig#0, namingS trategy,sessionFactory,jdbcTemplate,txManager,hibernateTemplate,现象GroupDao,现象Dao,discretePhenomenonDao];工厂层级DaoConfig的根构造...
- 252 [线程0] INFO org.springframework.beans.factory.support.DefaultListableBeanFactory
- 销毁单身在org.s[email protected]185572a:定义bean [org.springframework.context.annotation.internalConfigurationAnnotationProcessor,org.springframework.context.annotation.internalAutowiredAnnotationProcessor,org.springframework.context.annotation.internalRequiredAnnotationProcessor,org.springframework.context.annotation.internalCommonAnnotationProcessor,org.springframework.context.annotation .internalPersistenceAnnotationProcessor,daoConfig,com.bjk.observation.server.config.DataSourceConfig#0,dataSource,com.bjk.observation.server.config.HibernateConfig#0,namingStrategy,sessionFactory,jdbcTemplate,txManager ,hibernateTemplate,现象群岛,现象岛屿,离散现象岛屿];工厂层次结构的根
- 253 [线程-0]错误org.springframework.web.context。ContextLoader
- 上下文初始化失败org.springframework.beans.factory.BeanCreationException:创建名为'daoConfig'的bean时出错:注入自动装配的依赖关系失败;嵌套异常是org.springframework.beans.factory.BeanCreationException:无法自动装入字段:private com.bjk.observation.server.config.HibernateConfig com.bjk.observation.server.config.DaoConfig.hibernateConfig;嵌套异常是org.springframework.beans.factory.BeanCreationException:创建名为'com.bjk.observation.server.config.HibernateConfig#0'的bean时出错:Bean实例化失败;嵌套异常是org.springframework.beans.BeanInstantiationException:无法实例化bean类[com.bjk.observation.server.config.HibernateConfig]:构造函数抛出异常;嵌套的例外是显示java.lang.NullPointerException
我不知道为什么这会有帮助,因为标有@Configuration的类应该是它们自己的bean。尽管如此,我按照你的建议尝试了,尽管我的错误日志不同,但它仍然与未按正确顺序初始化的bean有关。 (调试器证实了这一点。) 我把你关于@Configuration的观点看作是对于工厂bean来说不是很好,事实上,我已经回到了老的可靠的XML配置,但我仍然想知道它是如何工作的。 – jhericks 2010-07-16 23:29:09