如何在Java Spring Boot中读取保存在Resources中的文件

时间：2017-05-05 22:05:27

标签： java spring file spring-boot

我想读取存储在Spring应用程序中的文件。我的文件存储在资源文件夹resources/dataset/test.txt中。我可以在目标目录中看到该文件，但是如何在Spring应用程序中加载它？

我尝试使用过资源，但这也没有用：

@Value("classpath:/resources/dataset/test.txt") private Resource aResource;

@RequestMapping("/") public String echoStarter() throws IOException
    {
        System.out.println(aResource.getFile());//throws Error
        return aResource.getFilename();
    }

我也试过File，但也没有工作。

See picture of my folder structure

我收到以下java.io.FileNotFoundException错误：

java.io.FileNotFoundException: class path resource [resources/dataset/test.txt] cannot be resolved to URL because it does not exist
    at org.springframework.core.io.ClassPathResource.getURL(ClassPathResource.java:187) ~[spring-core-4.3.8.RELEASE.jar:4.3.8.RELEASE]
    at org.springframework.core.io.AbstractFileResolvingResource.getFile(AbstractFileResolvingResource.java:48) ~[spring-core-4.3.8.RELEASE.jar:4.3.8.RELEASE]
    at com.example.EchoController.echoStarter(EchoController.java:55) ~[classes/:na]
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_92]
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_92]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_92]
    at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_92]
    at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:205) ~[spring-web-4.3.8.RELEASE.jar:4.3.8.RELEASE]
    at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:133) ~[spring-web-4.3.8.RELEASE.jar:4.3.8.RELEASE]
    at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:97) ~[spring-webmvc-4.3.8.RELEASE.jar:4.3.8.RELEASE]
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:827) ~[spring-webmvc-4.3.8.RELEASE.jar:4.3.8.RELEASE]
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:738) ~[spring-webmvc-4.3.8.RELEASE.jar:4.3.8.RELEASE]
    at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85) ~[spring-webmvc-4.3.8.RELEASE.jar:4.3.8.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:963) ~[spring-webmvc-4.3.8.RELEASE.jar:4.3.8.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:897) ~[spring-webmvc-4.3.8.RELEASE.jar:4.3.8.RELEASE]
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970) ~[spring-webmvc-4.3.8.RELEASE.jar:4.3.8.RELEASE]
    at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:861) ~[spring-webmvc-4.3.8.RELEASE.jar:4.3.8.RELEASE]
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:635) ~[tomcat-embed-core-8.5.14.jar:8.5.14]
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846) ~[spring-webmvc-4.3.8.RELEASE.jar:4.3.8.RELEASE]
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:742) ~[tomcat-embed-core-8.5.14.jar:8.5.14]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) ~[tomcat-embed-core-8.5.14.jar:8.5.14]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.14.jar:8.5.14]
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) ~[tomcat-embed-websocket-8.5.14.jar:8.5.14]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.14.jar:8.5.14]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.14.jar:8.5.14]
    at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99) ~[spring-web-4.3.8.RELEASE.jar:4.3.8.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.3.8.RELEASE.jar:4.3.8.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.14.jar:8.5.14]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.14.jar:8.5.14]
    at org.springframework.web.filter.HttpPutFormContentFilter.doFilterInternal(HttpPutFormContentFilter.java:105) ~[spring-web-4.3.8.RELEASE.jar:4.3.8.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.3.8.RELEASE.jar:4.3.8.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.14.jar:8.5.14]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.14.jar:8.5.14]
    at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:81) ~[spring-web-4.3.8.RELEASE.jar:4.3.8.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.3.8.RELEASE.jar:4.3.8.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.14.jar:8.5.14]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.14.jar:8.5.14]
    at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:197) ~[spring-web-4.3.8.RELEASE.jar:4.3.8.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.3.8.RELEASE.jar:4.3.8.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.14.jar:8.5.14]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.14.jar:8.5.14]
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:198) ~[tomcat-embed-core-8.5.14.jar:8.5.14]
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) [tomcat-embed-core-8.5.14.jar:8.5.14]
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:478) [tomcat-embed-core-8.5.14.jar:8.5.14]
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140) [tomcat-embed-core-8.5.14.jar:8.5.14]
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:80) [tomcat-embed-core-8.5.14.jar:8.5.14]
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87) [tomcat-embed-core-8.5.14.jar:8.5.14]
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342) [tomcat-embed-core-8.5.14.jar:8.5.14]
    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:799) [tomcat-embed-core-8.5.14.jar:8.5.14]
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66) [tomcat-embed-core-8.5.14.jar:8.5.14]
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:861) [tomcat-embed-core-8.5.14.jar:8.5.14]
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1455) [tomcat-embed-core-8.5.14.jar:8.5.14]
    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) [tomcat-embed-core-8.5.14.jar:8.5.14]
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) [na:1.8.0_92]
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) [na:1.8.0_92]
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-embed-core-8.5.14.jar:8.5.14]
    at java.lang.Thread.run(Thread.java:745) [na:1.8.0_92]

1 个答案:

答案 0 :(得分：0)

您使用的是classpath变量，classpath始终指向项目的source folder（因为默认情况下您的resources folder标记为source folder项目 - 大图标右下方的小黄色图标）。因此，当您需要在该文件夹中使用某个文件时，只需指定不含resources的链接，就像@M一样。 Czerwinski评论说：classpath:dataset/test.txt。如果您想使用File，那么只需使用File file = new File("classpath:dataset/test.txt");

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