Spring MVC：管理异常答案

【问题标题】：Spring MVC: manage ExceptionsSpring MVC：管理异常
【发布时间】：2016-11-15 12:49:54
【问题描述】：

我的 Spring Web 模型-视图-控制器 (MVC) 框架中有这个类。 Spring Web 模型-视图-控制器（MVC）框架的版本是 3.2.8

我有这个控制器

public class WelcomeController extends ViewController {


    @Autowired
    private UserService userService;

    @Autowired
    private SessionHelper sessionHelper;

    public ModelAndView handleRequest(final HttpServletRequest request, HttpServletResponse response) throws Exception {

        sessionHelper.invalidate(request, new String[] { SubmitController.CONFIRMATION_INFO,
                                                         SubmitController.CONFIRMATION_INFO2,
                                                         SubmitController.CONFIRMATION_INFO3,
                                                         "changePrdStatus"  });                 
        HttpSession session = request.getSession();

        DetailedUser ecasUser = (DetailedUser)request.getUserPrincipal();

        User usr = userService.getUserFromLDAP(ecasUser);


..
}

抛出这个异常

com.tdk.iop.domain.security.ApplicationException: more than 1 user with the same email
        at com.tdk.iop.dao.impl.UserDaoImpl.findByEmail(UserDaoImpl.java:195)
        at com.tdk.iop.services.impl.ServiceSupport.getEcasUser(ServiceSupport.java:46)
        at com.tdk.iop.services.impl.UserServiceImpl.getUserFromEcas(UserServiceImpl.java:37)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:606)
        at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:317)
        at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:183)
        at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:150)
        at org.springframework.aop.framework.adapter.MethodBeforeAdviceInterceptor.invoke(MethodBeforeAdviceInterceptor.java:51)
        at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
        at org.springframework.transaction.interceptor.TransactionInterceptor$1.proceedWithInvocation(TransactionInterceptor.java:96)
        at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:260)
        at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:94)
        at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
        at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:91)
        at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
        at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:204)
        at com.sun.proxy.$Proxy596.getUserFromEcas(Unknown Source)
        at com.tdk.iop.controller.welcome.WelcomeController.handleRequest(WelcomeController.java:64)
        at org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter.handle(SimpleControllerHandlerAdapter.java:48)

web.xml 上的这个

<error-page>
                <exception-type>com.tdk.iop.domain.security.ApplicationException</exception-type>
                <location>/errors/error500.do</location>
        </error-page>

但是申请没有到达Error500Controller

【问题讨论】：

我认为您的问题与方法签名有关。您将 spring-mvc 配置为处理 ApplicationException，但您的方法会抛出更通用的 Exception。或许你必须完善 spring-mvc 配置。
你必须在你的 spring 配置 xml 中添加 SimpleMappingExceptionHandler bean。检查此链接mkyong.com/spring-mvc/spring-mvc-exception-handling-example

标签： java spring spring-mvc

【解决方案1】：

这种异常可以用@ExceptionHandler处理。对于 e.g. 假设您可以通过 usr.getNumberOfUserWithSameEmail()

获取具有相同电子邮件的用户数

public ModelAndView handleRequest(final HttpServletRequest request, HttpServletResponse response) throws Exception {

        sessionHelper.invalidate(request, new String[] { SubmitController.CONFIRMATION_INFO,
                                                         SubmitController.CONFIRMATION_INFO2,
                                                         SubmitController.CONFIRMATION_INFO3,
                                                         "changePrdStatus"  });                 
        HttpSession session = request.getSession();

        DetailedUser ecasUser = (DetailedUser)request.getUserPrincipal();

        User usr = userService.getUserFromLDAP(ecasUser);

        Integer numOfUser = usr.getNumberOfUserWithSameEmail();
      if(numOfUser>1){
          throw new SameEmailException("more than 1 user with the same email");
         }
..
}

然后在上面的方法之后，创建了一个方法来拦截这个SameEmailException：

@ExceptionHandler(SameEmailException.class) // UserNotFoundException.java
    public ModelAndView handleException(SameEmailException e) {
        ModelAndView modelAndView = new ModelAndView("errorView"); 
        modelAndView.addObject("errorMessage", e.getMessage());
        return modelAndView;
    }

然后创建一个显示消息的视图（errorView.jsp）：

<%@ page contentType="text/html; charset=ISO-8859-1" %>
<html>
<head>
    <title>Error! </title>
</head>
<body>
    <h2>${errorMessage}</h2>
</body>
</html>

然后为 SameEmailException 创建单独的类：

public class SameEmailException extends Exception {

    public SameEmailException (String message) {
        super(message);

    }
}

【讨论】：