如何使用JNDI数据库连接Spring Boot和Spring数据使用嵌入式Tomcat？

Question

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'entityManagerFactory' defined in class path resource [org/springframework/boot/autoconfigure/orm/jpa/HibernateJpaAutoConfiguration.class]: Instantiation of bean failed; 
nested exception is org.springframework.beans.factory.BeanDefinitionStoreException: Factory method [public org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean org.springframework.boot.autoconfigure.orm.jpa.JpaBaseConfiguration.entityManagerFactory(org.springframework.boot.autoconfigure.orm.jpa.EntityManagerFactoryBuilder)] threw exception;
nested exception is org.springframework.jndi.JndiLookupFailureException: JndiObjectTargetSource failed to obtain new target object; 
nested exception is javax.naming.NameNotFoundException: Name [comp/env/jdbc/myDataSource] is not bound in this Context. Unable to find [comp].

Answer 1

Tomcat使用线程的上下文类加载器来确定要执行查找的JNDI上下文。如果线程上下文类加载器不是web应用程序类加载器，那么JNDI上下文是空的，因此查找失败。

问题是在启动期间执行的数据源的JNDI查找是在主线程上执行的，而主线程的TCCL不是Tomcat的web应用程序类加载器。您可以通过更新TomcatEmbeddedServletContainerFactorybean来设置线程上下文类加载器来解决这个问题。我还没有说服自己，这不是一个可怕的黑客，但它的工作…

以下是更新的bean：

@Bean
public TomcatEmbeddedServletContainerFactory tomcatFactory() {
    return new TomcatEmbeddedServletContainerFactory() {

        @Override
        protected TomcatEmbeddedServletContainer getTomcatEmbeddedServletContainer(
                Tomcat tomcat) {
            tomcat.enableNaming();
            TomcatEmbeddedServletContainer container = 
                    super.getTomcatEmbeddedServletContainer(tomcat);
            for (Container child: container.getTomcat().getHost().findChildren()) {
                if (child instanceof Context) {
                    ClassLoader contextClassLoader = 
                            ((Context)child).getLoader().getClassLoader();
                    Thread.currentThread().setContextClassLoader(contextClassLoader);
                    break;
                }
            }
            return container;
        }

        @Override
        protected void postProcessContext(Context context) {
            ContextResource resource = new ContextResource();
            resource.setName("jdbc/myDataSource");
            resource.setType(DataSource.class.getName());
            resource.setProperty("driverClassName", "your.db.Driver");
            resource.setProperty("url", "jdbc:yourDb");

            context.getNamingResources().addResource(resource);
        }
    };
}