springboot 多线程使用MultipartFile读取excel文件内容报错问题
springboot项目开启多线程
启动类加注解开启 @EnableAsync，实现类方法加注解 @Async
前端页面
报错信息
主线线程名称：http-nio-8051-exec-6 支线线程名称：threadPoolTaskExecutor-1 java.io.FileNotFoundException: C:\Users\dongao\AppData\Local\Temp\tomcat.1255209411477782290.8051\work\Tomcat\localhost\ROOT\upload_7d7b99e5_38da_4a03_93e0_bff20cb48022_00000000.tmp (系统找不到指定的文件。) at java.io.FileInputStream.open0(Native Method) at java.io.FileInputStream.open(FileInputStream.java:195) at java.io.FileInputStream.<init>(FileInputStream.java:138) at org.apache.tomcat.util.http.fileupload.disk.DiskFileItem.getInputStream(DiskFileItem.java:194) at org.apache.catalina.core.ApplicationPart.getInputStream(ApplicationPart.java:100) at org.springframework.web.multipart.support.StandardMultipartHttpServletRequest$StandardMultipartFile.getInputStream(StandardMultipartHttpServletRequest.java:250) at com.dongao.project.utils.UploadUtil.readExcel(UploadUtil.java:156) at com.dongao.project.utils.UploadUtil.readExcelToMap(UploadUtil.java:98) at com.dongao.project.importbatch.service.ImportBatchServiceImpl.importData(ImportBatchServiceImpl.java:161) at com.dongao.project.importbatch.service.ImportBatchServiceImpl$$FastClassBySpringCGLIB$$440ed2f6.invoke(<generated>) at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:218) at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:749) at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:163) at org.springframework.aop.aspectj.MethodInvocationProceedingJoinPoint.proceed(MethodInvocationProceedingJoinPoint.java:88) at com.dongao.support.cat.CatUtils.proceed(CatUtils.java:18) at com.dongao.support.cat.CatSpringAop.getObject(CatSpringAop.java:26) at com.dongao.support.cat.CatSpringAop.aroundServiceMethod(CatSpringAop.java:22) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at org.springframework.aop.aspectj.AbstractAspectJAdvice.invokeAdviceMethodWithGivenArgs(AbstractAspectJAdvice.java:644) at org.springframework.aop.aspectj.AbstractAspectJAdvice.invokeAdviceMethod(AbstractAspectJAdvice.java:633) at org.springframework.aop.aspectj.AspectJAroundAdvice.invoke(AspectJAroundAdvice.java:70) at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:294) at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:98) at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:93) at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:688) at com.dongao.project.importbatch.service.ImportBatchServiceImpl$$EnhancerBySpringCGLIB$$a16c4d4e.importData(<generated>) at com.dongao.project.importbatch.service.ImportBatchServiceImpl$$FastClassBySpringCGLIB$$440ed2f6.invoke(<generated>) at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:218) at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:749) at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:163) at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:294) at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:98) at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) at org.springframework.aop.interceptor.AsyncExecutionInterceptor.lambda$invoke$0(AsyncExecutionInterceptor.java:115) at java.util.concurrent.FutureTask.run(FutureTask.java:266) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) at java.lang.Thread.run(Thread.java:748) 17:36:46.137 25472 [threadPoolTaskExecutor-1] INFO com.ruoyi.framework.datasource.DynamicDataSourceContextHolder - [setDataSourceType,26] - 切换到SLAVE数据源 17:36:46.163 25472 [threadPoolTaskExecutor-1] ERROR org.springframework.aop.interceptor.SimpleAsyncUncaughtExceptionHandler - [handleUncaughtException,39] - Unexpected exception occurred invoking async method: public void com.dongao.project.importbatch.service.ImportBatchServiceImpl.importData(org.springframework.web.multipart.MultipartFile,java.lang.Long) throws java.lang.Exception java.lang.IndexOutOfBoundsException: Index: 0, Size: 0 at java.util.ArrayList.rangeCheck(ArrayList.java:653) at java.util.ArrayList.get(ArrayList.java:429) at com.dongao.project.importbatch.service.ImportBatchServiceImpl.importData(ImportBatchServiceImpl.java:178) at com.dongao.project.importbatch.service.ImportBatchServiceImpl$$FastClassBySpringCGLIB$$440ed2f6.invoke(<generated>) at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:218) at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:749) at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:163) at org.springframework.aop.aspectj.MethodInvocationProceedingJoinPoint.proceed(MethodInvocationProceedingJoinPoint.java:88) at com.dongao.support.cat.CatUtils.proceed(CatUtils.java:18) at com.dongao.support.cat.CatSpringAop.getObject(CatSpringAop.java:26) at com.dongao.support.cat.CatSpringAop.aroundServiceMethod(CatSpringAop.java:22) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at org.springframework.aop.aspectj.AbstractAspectJAdvice.invokeAdviceMethodWithGivenArgs(AbstractAspectJAdvice.java:644) at org.springframework.aop.aspectj.AbstractAspectJAdvice.invokeAdviceMethod(AbstractAspectJAdvice.java:633) at org.springframework.aop.aspectj.AspectJAroundAdvice.invoke(AspectJAroundAdvice.java:70) at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:294) at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:98) at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:93) at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:688) at com.dongao.project.importbatch.service.ImportBatchServiceImpl$$EnhancerBySpringCGLIB$$a16c4d4e.importData(<generated>) at com.dongao.project.importbatch.service.ImportBatchServiceImpl$$FastClassBySpringCGLIB$$440ed2f6.invoke(<generated>) at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:218) at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:749) at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:163) at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:294) at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:98) at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) at org.springframework.aop.interceptor.AsyncExecutionInterceptor.lambda$invoke$0(AsyncExecutionInterceptor.java:115) at java.util.concurrent.FutureTask.run(FutureTask.java:266) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) at java.lang.Thread.run(Thread.java:748)
问题分析
前端页面传过来的文件会存在临时文件夹中，如下
C:\Users\dongao\AppData\Local\Temp\tomcat.1255209411477782290.8051\work\Tomcat\localhost\ROOT\
这个时候如果单线程操作，即正常程序流程解析是不会有问题的；
如果走异步多线程解析文件，主线程已经结束了，临时文件会被清空，这时候再来读取文件就会报错
java.io.FileNotFoundException: C:\Users\dongao\AppData\Local\Temp\tomcat.1255209411477782290.8051\work\Tomcat\localhost\ROOT\upload_7d7b99e5_38da_4a03_93e0_bff20cb48022_00000000.tmp (系统找不到指定的文件。)
问题处理
由于主线程结束，临时文件被清空，导致多线程业务类无法获取到临时文件而报错(系统找不到指定的文件。)，此时可以在主线程中转换获取文件流信息
InputStream is = file.getInputStream();
文件流信息存储在内存中，多线程时也可以获取到文件内容，解决问题。
