java SpringMVC收到一个错误“There ready is controller bean method”，尽管同一个控制器中还有其他方法

Question

我正在用Spring MVC开发一个REST API。 它构建成功，但当我尝试将其部署到Tomcat 8.0.57时 它给出以下错误，表示我在该控制器中已经有一个bean方法。但是我没有任何两个同名或相同的方法

这是ApacheTomcat日志

    29-Nov-2017 18:29:41.796 INFO [http-nio-8087-exec-72] org.apache.catalina.core.ApplicationContext.log 1 Spring WebApplicationInitializers detected on classpath
29-Nov-2017 18:29:41.844 INFO [http-nio-8087-exec-72] org.apache.catalina.core.ApplicationContext.log Initializing Spring root WebApplicationContext
29-Nov-2017 18:29:42.783 SEVERE [http-nio-8087-exec-72] org.apache.catalina.core.StandardContext.listenerStart Exception sending context initialized event to listener instance of class org.springframework.web.context.ContextLoaderListener
 org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'requestMappingHandlerMapping' defined in org.springframework.web.servlet.config.annotation.DelegatingWebMvcConfiguration: Invocation of init method failed; nested exception is java.lang.IllegalStateException: Ambiguous mapping. Cannot map 'chatUserController' method 
public java.lang.String org.test.chatapi.controller.ChatUserController.saveUser(org.test.chatapi.model.User)
to {[],methods=[POST]}: There is already 'chatMessageController' bean method
public java.lang.Integer org.test.chatapi.controller.ChatMessageController.saveMessage(org.test.chatapi.model.Message) mapped.
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1578)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:545)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:482)
    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:775)
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:861)
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:541)
    at org.springframework.web.context.ContextLoader.configureAndRefreshWebApplicationContext(ContextLoader.java:444)
    at org.springframework.web.context.ContextLoader.initWebApplicationContext(ContextLoader.java:326)
    at org.springframework.web.context.ContextLoaderListener.contextInitialized(ContextLoaderListener.java:107)
    at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4736)
    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5181)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
    at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:725)
    at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:701)
    at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:717)
    at org.apache.catalina.startup.HostConfig.deployDescriptor(HostConfig.java:586)
    at org.apache.catalina.startup.HostConfig.deployApps(HostConfig.java:460)
    at org.apache.catalina.startup.HostConfig.check(HostConfig.java:1586)
    at sun.reflect.GeneratedMethodAccessor94.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.apache.tomcat.util.modeler.BaseModelMBean.invoke(BaseModelMBean.java:300)
    at com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.invoke(DefaultMBeanServerInterceptor.java:819)
    at com.sun.jmx.mbeanserver.JmxMBeanServer.invoke(JmxMBeanServer.java:801)
    at org.apache.catalina.manager.ManagerServlet.check(ManagerServlet.java:1460)
    at org.apache.catalina.manager.ManagerServlet.deploy(ManagerServlet.java:906)
    at org.apache.catalina.manager.ManagerServlet.doGet(ManagerServlet.java:344)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:622)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:291)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.netbeans.modules.web.monitor.server.MonitorFilter.doFilter(MonitorFilter.java:393)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.apache.catalina.filters.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:108)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:217)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:614)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:142)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
    at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:616)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:518)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1091)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:673)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1500)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1456)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.lang.Thread.run(Thread.java:748)
Caused by: java.lang.IllegalStateException: Ambiguous mapping. Cannot map 'chatUserController' method 
public java.lang.String org.test.chatapi.controller.ChatUserController.saveUser(org.test.chatapi.model.User)
to {[],methods=[POST]}: There is already 'chatMessageController' bean method
public java.lang.Integer org.test.chatapi.controller.ChatMessageController.saveMessage(org.test.chatapi.model.Message) mapped.
    at org.springframework.web.servlet.handler.AbstractHandlerMethodMapping$MappingRegistry.assertUniqueMethodMapping(AbstractHandlerMethodMapping.java:570)
    at org.springframework.web.servlet.handler.AbstractHandlerMethodMapping$MappingRegistry.register(AbstractHandlerMethodMapping.java:534)
    at org.springframework.web.servlet.handler.AbstractHandlerMethodMapping.registerHandlerMethod(AbstractHandlerMethodMapping.java:258)
    at org.springframework.web.servlet.handler.AbstractHandlerMethodMapping.detectHandlerMethods(AbstractHandlerMethodMapping.java:244)
    at org.springframework.web.servlet.handler.AbstractHandlerMethodMapping.initHandlerMethods(AbstractHandlerMethodMapping.java:214)
    at org.springframework.web.servlet.handler.AbstractHandlerMethodMapping.afterPropertiesSet(AbstractHandlerMethodMapping.java:184)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping.afterPropertiesSet(RequestMappingHandlerMapping.java:124)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1637)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1574)
    ... 59 more

29-Nov-2017 18:29:42.789 INFO [http-nio-8087-exec-72]  org.apache.catalina.core.ApplicationContext.log Closing Spring root      WebApplicationContext

这些是控制器。 聊天用户控制器

@RestController
public class ChatUserController {

// Store the Users temporarily
ArrayList<User> users = new ArrayList<>();

// Get all the online users
@RequestMapping(name = "/users/", method = RequestMethod.GET)
public ArrayList<User> getUsers(){
    users.add(new User("Janith","Hellow worlds"));
    return users;
}

// Save new user / User Login
@RequestMapping(name = "/users/",method = RequestMethod.POST)
public String saveUser(@RequestBody User user){
    if(user != null){
        users.add(user);
        return "Successfull Saved";
    }else{
        return "Failed";
    }
}

// Remove the user /  User sign out
@RequestMapping(name = "/users/{uname}", method = RequestMethod.DELETE)
public String deleteUser(@PathVariable String uname){
    for(User u:users){
        if(u.getUsername().equals(uname)){
            users.remove(u);
            return "Removed Successfully";
        }
    }
    return "User Not found. Should be already Deleted.";
}
}

聊天信息控制器

@RestController
public class ChatMessageController {

    ArrayList<Message> messagesList = new ArrayList<>(); 

    @RequestMapping(name = "/messages/{username}", method = RequestMethod.PUT)
    public ArrayList<Message> getChat(@PathVariable String username) {

        // create a new list of unread messages
        ArrayList<Message> myMessages = new ArrayList<>();

        // add the unread messages to list
        for (Message m : messagesList) {
            if (m.getReciever().equals(username)) {
                if (!m.isViewed()) {
                    m.setViewed(true);
                    myMessages.add(m);
                }
            }
        }       
        return myMessages;
    }

    @RequestMapping(name = "/messages/", method = RequestMethod.POST)
    public Integer saveMessage(@RequestBody Message message){
        if(message != null){
            message.setViewed(false);
            messagesList.add(message);
            return new Integer(1);
        }else{
            return new Integer(0);
        }
    }
}

但这个ChatUserController运行良好，我部署并测试了它。 添加ChatMessageController的第二个方法saveMessage（）后出现此错误。当第一个方法getChat（）在GET RequestMethod中时，也出现了同样的错误。在我把它改成PUT方法后，它被修复了。 我是Spring MVC Web API的新手，因此非常感谢您对我的帮助