already exists and could not be deleted

最近在做文件导入的功能，用到了easyExcel。在使用的过程中遇到一个问题，上传两次同名文件会报文件已存在，无法删除的错误。

方法如下：

public Object upload(MultipartFile file) throws IOException {
        //System.currentTimeMillis()+
        String fileName = file.getOriginalFilename();

        // TODO 怎么处理路径 不生成临时文件
        String tmpPath = System.getProperty("user.dir") + "/tmpPath/";
        File dest = new File(tmpPath+fileName);
        try{

            if(!dest.getParentFile().exists()){
                dest.getParentFile().mkdirs();
            }

            // 用来把 MultipartFile   转换成  File
            file.transferTo(dest);

            List<ReadSheet> readSheetList = EasyExcel.read(dest).build().excelExecutor().sheetList();
            for(ReadSheet readSheet:readSheetList) {
                EasyExcel.read(dest, UpmsPermission.class, new UpmsExcelListener<UpmsPermission>(ps))
                        .sheet(readSheet.getSheetName())
                        .doRead();

            }

            LOGGER.info("所有数据解析完成！");
            return new UpmsResult(UpmsResultConstant.SUCCESS, "success");
        } catch (Exception e) {
            e.printStackTrace();
            return new UpmsResult(UpmsResultConstant.FAILED, "文件上传失败");
        }

报错日志如下：

java.io.IOException: Destination file [D:\tools\apache-tomcat-9.0.50\bin\tmpPath\权限报表.xlsx] already exists and could not be deleted
    at org.springframework.web.multipart.commons.CommonsMultipartFile.transferTo(CommonsMultipartFile.java:160)
    at com.landspace.upms.server.controller.manage.UpmsSystemController.upload(UpmsSystemController.java:256)
    at com.landspace.upms.server.controller.manage.UpmsSystemController$$FastClassBySpringCGLIB$$10d9a401.invoke(<generated>)
    at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:204)
    at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:736)
2021-08-27 09:52:36,023 [http-nio-8098-exec-4] DEBUG [com.landspace.upms.client.interceptor.LogAspect] - doAround>>>result=com.landspace.upms.common.constant.UpmsResult@478ed714,耗时：4
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:157)
    at org.springframework.aop.framework.adapter.MethodBeforeAdviceInterceptor.invoke(MethodBeforeAdviceInterceptor.java:56)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
    at org.springframework.aop.aspectj.MethodInvocationProceedingJoinPoint.proceed(MethodInvocationProceedingJoinPoint.java:84)
    at com.landspace.upms.client.interceptor.LogAspect.doAround(LogAspect.java:65)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.springframework.aop.aspectj.AbstractAspectJAdvice.invokeAdviceMethodWithGivenArgs(AbstractAspectJAdvice.java:627)
    at org.springframework.aop.aspectj.AbstractAspectJAdvice.invokeAdviceMethod(AbstractAspectJAdvice.java:616)
    at org.springframework.aop.aspectj.AspectJAroundAdvice.invoke(AspectJAroundAdvice.java:70)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
    at org.springframework.aop.aspectj.AspectJAfterAdvice.invoke(AspectJAfterAdvice.java:47)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
    at org.apache.shiro.spring.security.interceptor.AopAllianceAnnotationsAuthorizingMethodInterceptor$1.proceed(AopAllianceAnnotationsAuthorizingMethodInterceptor.java:82)
    at org.apache.shiro.authz.aop.AuthorizingMethodInterceptor.invoke(AuthorizingMethodInterceptor.java:39)
    at org.apache.shiro.spring.security.interceptor.AopAllianceAnnotationsAuthorizingMethodInterceptor.invoke(AopAllianceAnnotationsAuthorizingMethodInterceptor.java:115)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
    at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:92)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
    at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:671)
    at com.landspace.upms.server.controller.manage.UpmsSystemController$$EnhancerBySpringCGLIB$$84930a74.upload(<generated>)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:205)
    at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:133)
    at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:97)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:849)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:760)
    at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85)
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:967)
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:901)
    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:681)
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:764)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:228)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:163)
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:190)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:163)
    at org.apache.shiro.web.servlet.ProxiedFilterChain.doFilter(ProxiedFilterChain.java:61)
    at org.apache.shiro.web.servlet.AdviceFilter.executeChain(AdviceFilter.java:108)
    at org.apache.shiro.web.servlet.AdviceFilter.doFilterInternal(AdviceFilter.java:137)
    at org.apache.shiro.web.servlet.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:125)
    at org.apache.shiro.web.servlet.ProxiedFilterChain.doFilter(ProxiedFilterChain.java:66)
    at org.apache.shiro.web.servlet.AdviceFilter.executeChain(AdviceFilter.java:108)
    at org.apache.shiro.web.servlet.AdviceFilter.doFilterInternal(AdviceFilter.java:137)
    at org.apache.shiro.web.servlet.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:125)
    at org.apache.shiro.web.servlet.ProxiedFilterChain.doFilter(ProxiedFilterChain.java:66)
    at org.apache.shiro.web.servlet.AbstractShiroFilter.executeChain(AbstractShiroFilter.java:449)
    at org.apache.shiro.web.servlet.AbstractShiroFilter$1.call(AbstractShiroFilter.java:365)
    at org.apache.shiro.subject.support.SubjectCallable.doCall(SubjectCallable.java:90)
    at org.apache.shiro.subject.support.SubjectCallable.call(SubjectCallable.java:83)
    at org.apache.shiro.subject.support.DelegatingSubject.execute(DelegatingSubject.java:383)
    at org.apache.shiro.web.servlet.AbstractShiroFilter.doFilterInternal(AbstractShiroFilter.java:362)
    at org.apache.shiro.web.servlet.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:125)
    at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:347)
    at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:263)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:190)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:163)
    at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:197)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:190)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:163)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:97)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:542)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:143)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)
    at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:687)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:78)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:357)
    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:382)
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65)
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:893)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1723)
    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.lang.Thread.run(Thread.java:748)

后经常调查发现是transferTo（）方法后面的操作引起流未关闭。

几种解决方案如下：

1.如果要保留上传文件的话，直接在上传文件的实际文件名上面加时间戳，这样能保证每次上传文件的名称不一样，不会造成上面的错误。示例如下：

String fileName =System.currentTimeMillis()+file.getOriginalFilename();

2.不需要保存上传文件的，可以以流的形式读取文件内容，即不需要进行文件转换了,修改后的方法如下：

public Object upload(MultipartFile file) throws IOException {
        try{
            List<ReadSheet> readSheetList = EasyExcel.read(file.getInputStream()).build().excelExecutor().sheetList();
            for(ReadSheet readSheet:readSheetList) {
                EasyExcel.read(file.getInputStream(), UpmsPermission.class, new UpmsExcelListener<UpmsPermission>(ps))
                        .sheet(readSheet.getSheetName())
                        .doRead();

            }

            LOGGER.info("所有数据解析完成！");
            return new UpmsResult(UpmsResultConstant.SUCCESS, "success");
        } catch (Exception e) {
            e.printStackTrace();
            return new UpmsResult(UpmsResultConstant.FAILED, "文件上传失败");
        }

3.按照原始写法，保存上传文件时以流的形式获取，操作完成之后将流关闭，不过这个方法没有试验过。