我有一个问题：
我有这个Java代码：
public void generate_mapping() throws FileNotFoundException {
String fileMapping = "./src/mappingFile.ttl";
SystemLoader loader = new SystemLoader();
File f = new File(mappingFile);
try {
f.createNewFile();
} catch (IOException ex) {
Logger.getLogger(Prova.class.getName()).log(Level.SEVERE, null, ex);
}
PrintStream out;
out = new PrintStream(new FileOutputStream(f));
MappingGenerator generator = loader.openMappingGenerator();
try {
generator.setInstanceNamespaceURI("http://Group");
generator.setVocabNamespaceURI("http://relation");
generator.writeMapping(out);
} finally {
loader.closeMappingGenerator();
}
}
此代码生成映射并使用D2RQ库。当我执行这个代码时，我从相对路径得到这个错误：
java.io.IOException: Impossibile trovare il percorso specificato
at java.io.WinNTFileSystem.createFileExclusively(Native Method)
at java.io.File.createNewFile(File.java:1006)
at MyPackage.Prova.generate_mapping(Prova.java:56)
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.glassfish.ejb.security.application.EJBSecurityManager.runMethod(EJBSecurityManager.java:1081)
at org.glassfish.ejb.security.application.EJBSecurityManager.invoke(EJBSecurityManager.java:1153)
at com.sun.ejb.containers.BaseContainer.invokeBeanMethod(BaseContainer.java:4695)
at com.sun.ejb.EjbInvocation.invokeBeanMethod(EjbInvocation.java:630)
at com.sun.ejb.containers.interceptors.AroundInvokeChainImpl.invokeNext(InterceptorManager.java:822)
at com.sun.ejb.EjbInvocation.proceed(EjbInvocation.java:582)
at org.jboss.weld.ejb.AbstractEJBRequestScopeActivationInterceptor.aroundInvoke(AbstractEJBRequestScopeActivationInterceptor.java:55)
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 com.sun.ejb.containers.interceptors.AroundInvokeInterceptor.intercept(InterceptorManager.java:883)
at com.sun.ejb.containers.interceptors.AroundInvokeChainImpl.invokeNext(InterceptorManager.java:822)
at com.sun.ejb.EjbInvocation.proceed(EjbInvocation.java:582)
at com.sun.ejb.containers.interceptors.SystemInterceptorProxy.doCall(SystemInterceptorProxy.java:163)
at com.sun.ejb.containers.interceptors.SystemInterceptorProxy.aroundInvoke(SystemInterceptorProxy.java:140)
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 com.sun.ejb.containers.interceptors.AroundInvokeInterceptor.intercept(InterceptorManager.java:883)
at com.sun.ejb.containers.interceptors.AroundInvokeChainImpl.invokeNext(InterceptorManager.java:822)
at com.sun.ejb.containers.interceptors.InterceptorManager.intercept(InterceptorManager.java:369)
at com.sun.ejb.containers.BaseContainer.__intercept(BaseContainer.java:4667)
at com.sun.ejb.containers.BaseContainer.intercept(BaseContainer.java:4655)
at com.sun.ejb.containers.WebServiceInvocationHandler.invoke(WebServiceInvocationHandler.java:193)
at com.sun.proxy.$Proxy299.publishLinkedOpenData(Unknown Source)
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.glassfish.webservices.InvokerImpl.invoke(InvokerImpl.java:82)
at org.glassfish.webservices.EjbInvokerImpl.invoke(EjbInvokerImpl.java:82)
at com.sun.xml.ws.server.InvokerTube$2.invoke(InvokerTube.java:149)
at com.sun.xml.ws.server.sei.SEIInvokerTube.processRequest(SEIInvokerTube.java:88)
at com.sun.xml.ws.api.pipe.Fiber.__doRun(Fiber.java:1136)
at com.sun.xml.ws.api.pipe.Fiber._doRun(Fiber.java:1050)
at com.sun.xml.ws.api.pipe.Fiber.doRun(Fiber.java:1019)
at com.sun.xml.ws.api.pipe.Fiber.runSync(Fiber.java:877)
at com.sun.xml.ws.api.pipe.helper.AbstractTubeImpl.process(AbstractTubeImpl.java:136)
at org.glassfish.webservices.MonitoringPipe.process(MonitoringPipe.java:142)
at com.sun.xml.ws.api.pipe.helper.PipeAdapter.processRequest(PipeAdapter.java:119)
at com.sun.xml.ws.api.pipe.Fiber.__doRun(Fiber.java:1136)
at com.sun.xml.ws.api.pipe.Fiber._doRun(Fiber.java:1050)
at com.sun.xml.ws.api.pipe.Fiber.doRun(Fiber.java:1019)
at com.sun.xml.ws.api.pipe.Fiber.runSync(Fiber.java:877)
at com.sun.xml.ws.api.pipe.helper.AbstractTubeImpl.process(AbstractTubeImpl.java:136)
at com.sun.enterprise.security.webservices.CommonServerSecurityPipe.processRequest(CommonServerSecurityPipe.java:210)
at com.sun.enterprise.security.webservices.CommonServerSecurityPipe.process(CommonServerSecurityPipe.java:142)
at com.sun.xml.ws.api.pipe.helper.PipeAdapter.processRequest(PipeAdapter.java:119)
at com.sun.xml.ws.api.pipe.Fiber.__doRun(Fiber.java:1136)
at com.sun.xml.ws.api.pipe.Fiber._doRun(Fiber.java:1050)
at com.sun.xml.ws.api.pipe.Fiber.doRun(Fiber.java:1019)
at com.sun.xml.ws.api.pipe.Fiber.runSync(Fiber.java:877)
at com.sun.xml.ws.server.WSEndpointImpl$2.process(WSEndpointImpl.java:420)
at com.sun.xml.ws.transport.http.HttpAdapter$HttpToolkit.handle(HttpAdapter.java:687)
at com.sun.xml.ws.transport.http.HttpAdapter.handle(HttpAdapter.java:266)
at com.sun.xml.ws.transport.http.servlet.ServletAdapter.handle(ServletAdapter.java:169)
at org.glassfish.webservices.Ejb3MessageDispatcher.handlePost(Ejb3MessageDispatcher.java:110)
at org.glassfish.webservices.Ejb3MessageDispatcher.invoke(Ejb3MessageDispatcher.java:80)
at org.glassfish.webservices.EjbWebServiceServlet.dispatchToEjbEndpoint(EjbWebServiceServlet.java:203)
at org.glassfish.webservices.EjbWebServiceServlet.service(EjbWebServiceServlet.java:146)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)
at org.glassfish.grizzly.servlet.ServletHandler.doServletService(ServletHandler.java:242)
at org.glassfish.grizzly.servlet.ServletHandler.service(ServletHandler.java:193)
at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:246)
at org.glassfish.grizzly.http.server.HttpHandler.runService(HttpHandler.java:191)
at org.glassfish.grizzly.http.server.HttpHandler.doHandle(HttpHandler.java:168)
at org.glassfish.grizzly.http.server.HttpServerFilter.handleRead(HttpServerFilter.java:189)
at org.glassfish.grizzly.filterchain.ExecutorResolver$9.execute(ExecutorResolver.java:119)
at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeFilter(DefaultFilterChain.java:288)
at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeChainPart(DefaultFilterChain.java:206)
at org.glassfish.grizzly.filterchain.DefaultFilterChain.execute(DefaultFilterChain.java:136)
at org.glassfish.grizzly.filterchain.DefaultFilterChain.process(DefaultFilterChain.java:114)
at org.glassfish.grizzly.ProcessorExecutor.execute(ProcessorExecutor.java:77)
at org.glassfish.grizzly.nio.transport.TCPNIOTransport.fireIOEvent(TCPNIOTransport.java:838)
at org.glassfish.grizzly.strategies.AbstractIOStrategy.fireIOEvent(AbstractIOStrategy.java:113)
at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.run0(WorkerThreadIOStrategy.java:115)
at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.access$100(WorkerThreadIOStrategy.java:55)
at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy$WorkerThreadRunnable.run(WorkerThreadIOStrategy.java:135)
at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:564)
at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.run(AbstractThreadPool.java:544)
at java.lang.Thread.run(Thread.java:744)
Grave: java.io.FileNotFoundException: .srcmappingFile.ttl (Impossibile trovare il percorso specificato)
at java.io.FileOutputStream.open(Native Method)
at java.io.FileOutputStream.<init>(FileOutputStream.java:221)
at java.io.FileOutputStream.<init>(FileOutputStream.java:171)
at MyPackage.Prova.generate_mapping(Prova.java:56)
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.glassfish.ejb.security.application.EJBSecurityManager.runMethod(EJBSecurityManager.java:1081)
at org.glassfish.ejb.security.application.EJBSecurityManager.invoke(EJBSecurityManager.java:1153)
at com.sun.ejb.containers.BaseContainer.invokeBeanMethod(BaseContainer.java:4695)
at com.sun.ejb.EjbInvocation.invokeBeanMethod(EjbInvocation.java:630)
at com.sun.ejb.containers.interceptors.AroundInvokeChainImpl.invokeNext(InterceptorManager.java:822)
at com.sun.ejb.EjbInvocation.proceed(EjbInvocation.java:582)
at org.jboss.weld.ejb.AbstractEJBRequestScopeActivationInterceptor.aroundInvoke(AbstractEJBRequestScopeActivationInterceptor.java:55)
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 com.sun.ejb.containers.interceptors.AroundInvokeInterceptor.intercept(InterceptorManager.java:883)
at com.sun.ejb.containers.interceptors.AroundInvokeChainImpl.invokeNext(InterceptorManager.java:822)
at com.sun.ejb.EjbInvocation.proceed(EjbInvocation.java:582)
at com.sun.ejb.containers.interceptors.SystemInterceptorProxy.doCall(SystemInterceptorProxy.java:163)
at com.sun.ejb.containers.interceptors.SystemInterceptorProxy.aroundInvoke(SystemInterceptorProxy.java:140)
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 com.sun.ejb.containers.interceptors.AroundInvokeInterceptor.intercept(InterceptorManager.java:883)
at com.sun.ejb.containers.interceptors.AroundInvokeChainImpl.invokeNext(InterceptorManager.java:822)
at com.sun.ejb.containers.interceptors.InterceptorManager.intercept(InterceptorManager.java:369)
at com.sun.ejb.containers.BaseContainer.__intercept(BaseContainer.java:4667)
at com.sun.ejb.containers.BaseContainer.intercept(BaseContainer.java:4655)
at com.sun.ejb.containers.WebServiceInvocationHandler.invoke(WebServiceInvocationHandler.java:193)
at com.sun.proxy.$Proxy299.publishLinkedOpenData(Unknown Source)
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.glassfish.webservices.InvokerImpl.invoke(InvokerImpl.java:82)
at org.glassfish.webservices.EjbInvokerImpl.invoke(EjbInvokerImpl.java:82)
at com.sun.xml.ws.server.InvokerTube$2.invoke(InvokerTube.java:149)
at com.sun.xml.ws.server.sei.SEIInvokerTube.processRequest(SEIInvokerTube.java:88)
at com.sun.xml.ws.api.pipe.Fiber.__doRun(Fiber.java:1136)
at com.sun.xml.ws.api.pipe.Fiber._doRun(Fiber.java:1050)
at com.sun.xml.ws.api.pipe.Fiber.doRun(Fiber.java:1019)
at com.sun.xml.ws.api.pipe.Fiber.runSync(Fiber.java:877)
at com.sun.xml.ws.api.pipe.helper.AbstractTubeImpl.process(AbstractTubeImpl.java:136)
at org.glassfish.webservices.MonitoringPipe.process(MonitoringPipe.java:142)
at com.sun.xml.ws.api.pipe.helper.PipeAdapter.processRequest(PipeAdapter.java:119)
at com.sun.xml.ws.api.pipe.Fiber.__doRun(Fiber.java:1136)
at com.sun.xml.ws.api.pipe.Fiber._doRun(Fiber.java:1050)
at com.sun.xml.ws.api.pipe.Fiber.doRun(Fiber.java:1019)
at com.sun.xml.ws.api.pipe.Fiber.runSync(Fiber.java:877)
at com.sun.xml.ws.api.pipe.helper.AbstractTubeImpl.process(AbstractTubeImpl.java:136)
at com.sun.enterprise.security.webservices.CommonServerSecurityPipe.processRequest(CommonServerSecurityPipe.java:210)
at com.sun.enterprise.security.webservices.CommonServerSecurityPipe.process(CommonServerSecurityPipe.java:142)
at com.sun.xml.ws.api.pipe.helper.PipeAdapter.processRequest(PipeAdapter.java:119)
at com.sun.xml.ws.api.pipe.Fiber.__doRun(Fiber.java:1136)
at com.sun.xml.ws.api.pipe.Fiber._doRun(Fiber.java:1050)
at com.sun.xml.ws.api.pipe.Fiber.doRun(Fiber.java:1019)
at com.sun.xml.ws.api.pipe.Fiber.runSync(Fiber.java:877)
at com.sun.xml.ws.server.WSEndpointImpl$2.process(WSEndpointImpl.java:420)
at com.sun.xml.ws.transport.http.HttpAdapter$HttpToolkit.handle(HttpAdapter.java:687)
at com.sun.xml.ws.transport.http.HttpAdapter.handle(HttpAdapter.java:266)
at com.sun.xml.ws.transport.http.servlet.ServletAdapter.handle(ServletAdapter.java:169)
at org.glassfish.webservices.Ejb3MessageDispatcher.handlePost(Ejb3MessageDispatcher.java:110)
at org.glassfish.webservices.Ejb3MessageDispatcher.invoke(Ejb3MessageDispatcher.java:80)
at org.glassfish.webservices.EjbWebServiceServlet.dispatchToEjbEndpoint(EjbWebServiceServlet.java:203)
at org.glassfish.webservices.EjbWebServiceServlet.service(EjbWebServiceServlet.java:146)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)
at org.glassfish.grizzly.servlet.ServletHandler.doServletService(ServletHandler.java:242)
at org.glassfish.grizzly.servlet.ServletHandler.service(ServletHandler.java:193)
at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:246)
at org.glassfish.grizzly.http.server.HttpHandler.runService(HttpHandler.java:191)
at org.glassfish.grizzly.http.server.HttpHandler.doHandle(HttpHandler.java:168)
at org.glassfish.grizzly.http.server.HttpServerFilter.handleRead(HttpServerFilter.java:189)
at org.glassfish.grizzly.filterchain.ExecutorResolver$9.execute(ExecutorResolver.java:119)
at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeFilter(DefaultFilterChain.java:288)
at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeChainPart(DefaultFilterChain.java:206)
at org.glassfish.grizzly.filterchain.DefaultFilterChain.execute(DefaultFilterChain.java:136)
at org.glassfish.grizzly.filterchain.DefaultFilterChain.process(DefaultFilterChain.java:114)
at org.glassfish.grizzly.ProcessorExecutor.execute(ProcessorExecutor.java:77)
at org.glassfish.grizzly.nio.transport.TCPNIOTransport.fireIOEvent(TCPNIOTransport.java:838)
at org.glassfish.grizzly.strategies.AbstractIOStrategy.fireIOEvent(AbstractIOStrategy.java:113)
at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.run0(WorkerThreadIOStrategy.java:115)
at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.access$100(WorkerThreadIOStrategy.java:55)
at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy$WorkerThreadRunnable.run(WorkerThreadIOStrategy.java:135)
at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:564)
at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.run(AbstractThreadPool.java:544)
at java.lang.Thread.run(Thread.java:744)
我的问题是：如何使用相对路径编写文件？写了这个文件之后，我该怎么读？我正在使用Netbeans。
您应该这样做：
Path relativePath = Paths.get("<put your path here>");
Path absolutePath = relativePath.toAbsolutePath();
System.out.println("Current relative path is: " + absolutePath.toString());
另一种选择可能是：
String workingDir = System.getProperty("user.dir");
这会给你当前的工作目录，然后从它开始工作。
编辑
对于您在评论中所说的内容：使用相对路径没有问题，那么你的问题可能是这些替代方案之一：
基本路径不是你认为的
我上面写的同样的行应该可以帮助你调试问题，使用它们你可以看到你得到的绝对路径，当然它不会是你认为的那样
问题是"&"；，我还没有测试过，但也许这会给你带来一些窗户下的问题。
src目录不存在，也许它将我们带到第一点，或者（取决于您的应用程序）它没有创建/安装。。。
但是，即使你想使用相对路径，在某个时候（即使你没有明确地这样做），它们也会被转换为绝对路径，所以在使用它们之前将它们转换为绝对道路不会对你造成伤害，至少在调试时或当你对使用路径有信心时是这样。
使用相对路径没有问题。但你需要知道你在哪个目录下，这样你就知道它是从哪里来的相对路径！它不会相对于你的项目目录，除非你碰巧在那里运行。
您需要使用类加载器来查找与您的项目相关的资源。
你想要类似的东西：
java.net.URL imgURL = ImageTools.class.getResource(path);
if (imgURL != null) {
return new ImageIcon(imgURL, description);
} else {
log.error("Couldn't find file: " + path);
return null;
}
其中ImageTools是它所包含的类。您给它的路径应该以/开头，但它会从项目中/src的子目录中获取资源。这样做的好处是，当您的项目构建为jar文件时，它也会起作用。
这是我用来生成一个用于Swing项目的ImageIcon的代码，这只是一个示例，您就明白了。它会为您提供一个URL，您可以使用该URL访问该文件。
（不过，你正在做的事情有点奇怪，因为你正试图创建一个文件。/src目录真的不是合适的地方。我给你的代码是用来访问项目中的资源并读取它们；如果你试图创建新文件，那么你想把它们完全放在其他地方。）