BeanCreationException：创建名为"springApplicationAdminRegistrar"的 Bean 时出错。InstanceAlreadyExistException

Question

>我有 2 个弹簧启动应用程序。

application_A dependsn_on application_B

实际上，每个应用程序的主类都标记为@SpringBootApplication

application_B成功启动，但application_A未启动：

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'springApplicationAdminRegistrar' defined in class path resource [org/springframework/boot/autoconfigure/admin/SpringApplicationAdminJmxAutoConfiguration.class]: Invocation of init method failed; nested exception is javax.management.InstanceAlreadyExistsException: org.springframework.boot:type=Admin,name=SpringApplication # JMX name of the application admin MBean.
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1628)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:555)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:483)
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:761)
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:867)
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:543)
    at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:693)
    at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:360)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:303)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1118)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1107)
    at pack.Application.main(Application.java:36)
Caused by: javax.management.InstanceAlreadyExistsException: org.springframework.boot:type=Admin,name=SpringApplication # JMX name of the application admin MBean.
    at com.sun.jmx.mbeanserver.Repository.addMBean(Repository.java:437)
    at com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.registerWithRepository(DefaultMBeanServerInterceptor.java:1898)
    at com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.registerDynamicMBean(DefaultMBeanServerInterceptor.java:966)
    at com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.registerObject(DefaultMBeanServerInterceptor.java:900)
    at com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.registerMBean(DefaultMBeanServerInterceptor.java:324)
    at com.sun.jmx.mbeanserver.JmxMBeanServer.registerMBean(JmxMBeanServer.java:522)
    at org.springframework.boot.admin.SpringApplicationAdminMXBeanRegistrar.afterPropertiesSet(SpringApplicationAdminMXBeanRegistrar.java:92)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1687)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1624)
    ... 15 common frames omitted

在调试中，我看到 spring 在启动期间执行org.springframework.boot.autoconfigure.admin.SpringApplicationAdminJmxAutoConfiguration#springApplicationAdminRegistrar两次并失败。

我尝试设置属性：

 spring.application.admin.enabled=false

但这对我没有帮助。

如何避免此异常？

附言

我找到了这个 https://github.com/spring-projects/spring-boot/issues/6378 但没有解决方案

Answer 1

如果有人仍然面临有关此的任何问题，您可以考虑以下情况：正如有人提到的那样"我偶尔调用了两次SpringApplication.run(Application.class, args);">

对我有用的解决方案：我们应该通过不同的类开始application(ApplicationContext)，即@SpringBootApplication注释类之外的类。

原因：@SpringBootApplication是三个注释的组合：@ComponentScan、@EnableAutoConfiguration和@Configuration，因此已经创建一个实例。因此，当我们在同一类中创建另一个应用程序上下文接口实例(xml或基于注释(时，它会遇到已经创建的实例并抛出异常。

Answer 2

SpringApplicationAdminJmxAutoConfiguration的代码如下：

String jmxName = this.environment.getProperty(JMX_NAME_PROPERTY,
            DEFAULT_JMX_NAME);
    if (this.mbeanExporters != null) { // Make sure to not register that MBean twice
        for (MBeanExporter mbeanExporter : this.mbeanExporters) {
            mbeanExporter.addExcludedBean(jmxName);
        }
    }
    return new SpringApplicationAdminMXBeanRegistrar(jmxName);

我们有这些常量的地方：

/**
 * The property to use to customize the {@code ObjectName} of the application admin
 * mbean.
 */
private static final String JMX_NAME_PROPERTY = "spring.application.admin.jmx-name";
/**
 * The default {@code ObjectName} of the application admin mbean.
 */
private static final String DEFAULT_JMX_NAME = "org.springframework.boot:type=Admin,name=SpringApplication";

因此，您应该考虑使该jmx-name对于每个应用程序都是唯一的。我的意思是您需要指定spring.application.admin.jmx-name配置属性。