Question

我编写代码以在我的工作目录中自动创建文件。

路径正常，但我已经给出了完整的系统路径，现在我想在没有E:\\Hello\\的资源文件夹中创建文件

现在路径是，

E:\\Hello\\file.txt

我想要

resources/file.txt

我的控制器

String message= "Hello World";
try {
    Files.write(Paths.get("E:\\Hello\\Hello\\file.txt"), message, StandardCharsets.UTF_8, StandardOpenOption.CREATE);
} catch (IOException e) {
    e.printStackTrace();
}

我的堆栈跟踪

May 14, 2018 6:39:26 PM org.apache.catalina.core.StandardWrapperValve invoke
SEVERE: Servlet.service() for servlet [SpringDispatcher] in context with path [/Hello] threw exception [Request processing failed; nested exception is java.lang.NullPointerException] with root cause
java.lang.NullPointerException
    at liteOn.controller.HomeController.tmax(HomeController.java:95)
    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.doInvoke(InvocableHandlerMethod.java:220)
    at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:134)
    at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:116)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:827)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:738)
    at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85)
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:963)
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:897)
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970)
    at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:872)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:661)
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:742)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:199)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:81)
    at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:650)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342)
    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:803)
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:790)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1459)
    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.lang.Thread.run(Unknown Source)

由于

Answer 1

试试这个：

String fileName = "static/java.ini"; 
Files.write(Paths.get(getClass().getClassLoader().getResource(fileName).toString()), data, StandardCharsets.UTF_8, StandardOpenOption.CREATE);

您将获得Spring Application根目录的路径。

<强>更新

要访问使用上述方法生成的文件，请尝试以下代码：

@Service
public class SomeServiceImpl {

    public String reader(String fileName) {
        try {
            Path path = Paths.get(getClass().getClassLoader().getResource(fileName).toURI());
            StringBuilder data = new StringBuilder();
            Stream<String> lines = Files.lines(path);
            lines.forEach((String line) -> data.append(line).append("\n"));
            lines.close();

            path = null;
            return data.toString();

        } catch (URISyntaxException e) {
            e.printStackTrace();
            return null;
        } catch (IOException e) {
            e.printStackTrace();
            return null;
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
    }
}

Answer 2

此代码在我的资源文件夹中创建了file.txt。然后tomcat文件夹检查了我的项目文件夹Hello，在该项目文件夹里面已经创建了资源文件夹file.txt。

String message= "Hello World";

String realPath  = request.getSession().getServletContext().getRealPath("/resources/file.txt");

Files.write(Paths.get(realPath), message, StandardCharsets.UTF_8, StandardOpenOption.CREATE);

在Spring MVC控制器中更改文件写入路径

2 个答案: