如何閱讀Java中資源中保存的文件Spring Boot

我想讀取存儲在我的Spring應用程序中的文件。我的文件存儲在資源文件夾resources/dataset/test.txt中。我可以在目標目錄中看到該文件，但是如何將它加載到我的Spring應用程序中？如何閱讀Java中資源中保存的文件Spring Boot

我試圖使用資源，但沒有工作，要麼：

@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(); 
    }

我也試圖與File但也不能工作。

See picture of my folder structure

我正在以下java.io.FileNotFoundException錯誤：

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]

來源

2017-05-05 Menelaos Kotsollaris

嘗試'@Value（「classpath：dataset/test.txt」）' –

謝謝你的作品！有關如何使用[File]（https://docs.oracle.com/javase/7/docs/api/java/io/File.html）庫實現同樣目標的任何想法？寫下您的評論作爲答案，以便我可以將其標記爲正確。 –

您正在使用classpath變量和classpath總是指向項目的source folder（因爲你resources folder在默認情況下是標記爲項目的source folder - 大圖標右下角的小黃色圖標）。因此，當您需要在該文件夾中使用某個文件時，只需指定不帶resources的鏈接就像@M。 Czerwinski評論說：classpath:dataset/test.txt。如果你想使用File然後只是File file = new File("classpath:dataset/test.txt");

來源

2017-05-06 01:48:19

如何閱讀Java中資源中保存的文件Spring Boot

回答

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