如何为新的FileNotFoundException ()捕获ClassPathXmlApplicationContext

Question

我试图创建一个程序，在这里我想输入来自用户的spring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，它将抛出FileNotFoundException。

我希望捕捉到此异常，并向用户显示一条错误消息，而不是终止应用程序。即使我用try-catch包围对构造函数的调用或使用throws声明，异常也不会被捕获，并且应用程序终止打印堆栈跟踪。

我怎么才能抓到抛出的异常呢？这是一个Spring应用程序

调用函数(在@Controller类中)-

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";
}

调用的函数(在来自不同包的其他普通类FlavourService中)-

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，因为-

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中创建一个类似的问题，就会得到一个不同的异常，其中它提到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

Answer 1

• 使用更高级别的异常来捕获，比如IOException。可能会发生这样的情况:您只捕获FileNotFoundException，并且可能会抛出其他类型的异常弹簧。
• 使用FileSystemXmlApplicationContext作为参数传递FileSystem路径。

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

Answer 2

在传递构造函数中的文件路径之前创建一个新的File对象，并检查该文件是否确实存在

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