如何为新的 ClassPathXmlApplicationContext() 捕获 FileNotFoundException答案

【问题标题】：How to catch FileNotFoundException for new ClassPathXmlApplicationContext()如何为新的 ClassPathXmlApplicationContext() 捕获 FileNotFoundException
【发布时间】：2015-03-11 06:50:29
【问题描述】：

我正在尝试创建一个程序，我想在其中输入来自用户的弹簧配置文件只是为了创建一些演示应用程序。如果我直接调用new ClassPathXmlApplicationContext(filePath)，如果文件不存在，它会抛出FileNotFoundException。

我想捕获此异常并向用户显示错误消息，而不是终止应用程序。即使我通过try-catch 或使用throws 声明来包围对构造函数的调用，也不会捕获到异常并且应用程序终止打印堆栈跟踪。

任何想法如何捕获抛出的异常？这是一个 Spring MVC 应用程序

调用函数（在@Controller类内）-

private String getFlavours(ModelMap model, String configFile) {
    FlavourService flavourService = new FlavourService();
    String results = null;

    try {
        results = flavourService.generateFlavour(configFile);
    } catch (FileNotFoundException e) {
        System.out.println("In FNF Execp");
        model.addAttribute("errorMessage", "Requested configurations file not found");
        return "index";
    }

    model.addAttribute("results", results);
    model.addAttribute("configFile", configFile);
    return "springDemo";
}

被调用的函数（在其他普通类FlavourService中来自不同的包）-

public String generateFlavour(String configFile) throws FileNotFoundException {
    String path = "somepath"; //this is path from classpath
    String filename = configFile;

    context = new ClassPathXmlApplicationContext(path + filename);

    //code to generate required output

    return output;
}

我得到了例外 -

SEVERE: Servlet.service() for servlet HelloWeb threw exception
java.io.FileNotFoundException: class path resource [com/cts/spring/config/dsf] cannot be opened because it does not exist
    at org.springframework.core.io.ClassPathResource.getInputStream(ClassPathResource.java:158)
    at org.springframework.beans.factory.xml.XmlBeanDefinitionReader.loadBeanDefinitions(XmlBeanDefinitionReader.java:329)
    at org.springframework.beans.factory.xml.XmlBeanDefinitionReader.loadBeanDefinitions(XmlBeanDefinitionReader.java:303)
    at org.springframework.beans.factory.support.AbstractBeanDefinitionReader.loadBeanDefinitions(AbstractBeanDefinitionReader.java:180)
    at org.springframework.beans.factory.support.AbstractBeanDefinitionReader.loadBeanDefinitions(AbstractBeanDefinitionReader.java:216)
    at org.springframework.beans.factory.support.AbstractBeanDefinitionReader.loadBeanDefinitions(AbstractBeanDefinitionReader.java:187)
    at org.springframework.beans.factory.support.AbstractBeanDefinitionReader.loadBeanDefinitions(AbstractBeanDefinitionReader.java:251)
    at org.springframework.context.support.AbstractXmlApplicationContext.loadBeanDefinitions(AbstractXmlApplicationContext.java:127)
    at org.springframework.context.support.AbstractXmlApplicationContext.loadBeanDefinitions(AbstractXmlApplicationContext.java:93)
    at org.springframework.context.support.AbstractRefreshableApplicationContext.refreshBeanFactory(AbstractRefreshableApplicationContext.java:129)
    at org.springframework.context.support.AbstractApplicationContext.obtainFreshBeanFactory(AbstractApplicationContext.java:540)
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:454)
    at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:139)
    at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:83)
    at com.cts.spring.FlavourService.generateFlavour(FlavourService.java:31)
    at com.cts.spring.controller.SpringFlavoursController.getFlavours(SpringFlavoursController.java:38)
    at com.cts.spring.controller.SpringFlavoursController.viewFlavours(SpringFlavoursController.java:30)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at org.springframework.web.method.support.InvocableHandlerMethod.invoke(InvocableHandlerMethod.java:215)
    at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:132)
    at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:104)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandleMethod(RequestMappingHandlerAdapter.java:749)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:690)
    at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:83)
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:945)
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:876)
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:961)
    at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:863)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:641)
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:837)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:243)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:201)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:163)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:108)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:402)
    at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:249)
    at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:267)
    at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:245)
    at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:260)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
    at java.lang.Thread.run(Unknown Source)

如果我尝试仅使用 spring 在 Java 项目中创建类似问题，我会得到一个不同的异常，其中提到 FileNotFoundException 是嵌套异常，如下所示 -

Exception in thread "main" org.springframework.beans.factory.BeanDefinitionStoreException: IOException parsing XML document from class path resource [dsf]; nested exception is java.io.FileNotFoundException: class path resource [dsf] cannot be opened because it does not exist
    at org.springframework.beans.factory.xml.XmlBeanDefinitionReader.loadBeanDefinitions(XmlBeanDefinitionReader.java:343)
    at org.springframework.beans.factory.xml.XmlBeanDefinitionReader.loadBeanDefinitions(XmlBeanDefinitionReader.java:303)
    at org.springframework.beans.factory.support.AbstractBeanDefinitionReader.loadBeanDefinitions(AbstractBeanDefinitionReader.java:180)
    at org.springframework.beans.factory.support.AbstractBeanDefinitionReader.loadBeanDefinitions(AbstractBeanDefinitionReader.java:216)
    at org.springframework.beans.factory.support.AbstractBeanDefinitionReader.loadBeanDefinitions(AbstractBeanDefinitionReader.java:187)
    at org.springframework.beans.factory.support.AbstractBeanDefinitionReader.loadBeanDefinitions(AbstractBeanDefinitionReader.java:251)
    at org.springframework.context.support.AbstractXmlApplicationContext.loadBeanDefinitions(AbstractXmlApplicationContext.java:127)
    at org.springframework.context.support.AbstractXmlApplicationContext.loadBeanDefinitions(AbstractXmlApplicationContext.java:93)
    at org.springframework.context.support.AbstractRefreshableApplicationContext.refreshBeanFactory(AbstractRefreshableApplicationContext.java:129)
    at org.springframework.context.support.AbstractApplicationContext.obtainFreshBeanFactory(AbstractApplicationContext.java:540)
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:454)
    at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:139)
    at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:83)
    at MainApp.main(MainApp.java:16)
Caused by: java.io.FileNotFoundException: class path resource [dsf] cannot be opened because it does not exist
    at org.springframework.core.io.ClassPathResource.getInputStream(ClassPathResource.java:158)
    at org.springframework.beans.factory.xml.XmlBeanDefinitionReader.loadBeanDefinitions(XmlBeanDefinitionReader.java:329)
    ... 13 more

【问题讨论】：

很明显，它并没有抛出 FileNotFoundException，所以你当然抓不到它。
@Raedwald 正如您在第一种情况（我的实际应用程序）中看到的那样，它显示FileNotFoundException 在后一种情况下，我知道它是一个嵌套异常。我该如何处理？因为我不想通过使用一些异常的超类来处理嵌套异常来搞乱异常处理
另见stackoverflow.com/questions/7593535/…

标签： java spring

【解决方案1】：

使用更高级别的异常来捕获，例如 IOException。您可能只捕获 FileNotFoundException 并且可能会抛出其他类型的异常 spring。
改用 FileSystemXmlApplicationContext，将 FileSystem 路径作为参数传递。

http://docs.spring.io/spring/docs/current/javadoc-api/org/springframework/context/support/FileSystemXmlApplicationContext.html#FileSystemXmlApplicationContext-java.lang.String-

【讨论】：

感谢您的想法。它对IOException 不起作用，但对Exception 起作用，就像一个魅力。它给了我FileNotFoundException 的嵌套异常。我想知道，如果代码由于其他原因引发了其他异常，我如何才能捕获嵌套异常，因为捕获Exception类型的异常可能无效。

【解决方案2】：

在构造函数中传递文件路径之前创建一个新的文件对象并检查该文件是否实际存在

试试这个

File file=new File(filePath);
if(!file.exists) // Check if file Actually Exists or not 
 //thow any Exception if file Not Exists

【讨论】：

这是处理问题的好主意（可能对实时应用程序有好处），但是当我学习 Java 中的概念时，我想知道如何处理异常而不是查找解决问题的另一种方法。
这不是一种替代方法，您获得FileNotFound Exception 后的第一次尝试是什么？您将创建该文件或只是 Quit ，您也可以从这里进行。