年后放假回來，一向運行OK的項目突然圖片上傳不了了，后台報錯日志如下：
java.io.IOException: The temporary upload location [/tmp/tomcat.7678703764679158021.8085/work/Tomcat/localhost/ROOT] is not valid
at org.apache.catalina.connector.Request.parseParts(Request.java:2839) ~[tomcat-embed-core-8.5.23.jar!/:8.5.23]
at org.apache.catalina.connector.Request.parseParameters(Request.java:3211) ~[tomcat-embed-core-8.5.23.jar!/:8.5.23]
at org.apache.catalina.connector.Request.getParameter(Request.java:1137) ~[tomcat-embed-core-8.5.23.jar!/:8.5.23]
at org.apache.catalina.connector.RequestFacade.getParameter(RequestFacade.java:381) ~[tomcat-embed-core-8.5.23.jar!/:8.5.23]
at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:75) ~[spring-web-4.3.13.RELEASE.jar!/:4.3.13.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.3.13.RELEASE.jar!/:4.3.13.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.23.jar!/:8.5.23]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.23.jar!/:8.5.23]
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:197) ~[spring-web-4.3.13.RELEASE.jar!/:4.3.13.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.3.13.RELEASE.jar!/:4.3.13.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.23.jar!/:8.5.23]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.23.jar!/:8.5.23]
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:199) ~[tomcat-embed-core-8.5.23.jar!/:8.5.23]
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) [tomcat-embed-core-8.5.23.jar!/:8.5.23]
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:478) [tomcat-embed-core-8.5.23.jar!/:8.5.23]
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140) [tomcat-embed-core-8.5.23.jar!/:8.5.23]
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:81) [tomcat-embed-core-8.5.23.jar!/:8.5.23]
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87) [tomcat-embed-core-8.5.23.jar!/:8.5.23]
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342) [tomcat-embed-core-8.5.23.jar!/:8.5.23]
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:803) [tomcat-embed-core-8.5.23.jar!/:8.5.23]
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66) [tomcat-embed-core-8.5.23.jar!/:8.5.23]
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:868) [tomcat-embed-core-8.5.23.jar!/:8.5.23]
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1459) [tomcat-embed-core-8.5.23.jar!/:8.5.23]
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) [tomcat-embed-core-8.5.23.jar!/:8.5.23]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) [na:1.8.0_74]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) [na:1.8.0_74]
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-embed-core-8.5.23.jar!/:8.5.23]
at java.lang.Thread.run(Thread.java:745) [na:1.8.0_74]
錯誤顯示上傳的臨時文件路勁/tmp/tomcat.7678703764679158021.8085/work/Tomcat/localhost/ROOT不可用，服務器上查看了下確實沒有該目錄。
錯誤原因：之前運行良好是因為，springboot啟動時會創建一個/tmp/tomcat.7*/work/Tomcat/localhost/ROOT的臨時目錄作為文件上傳的臨時目錄，但是該目錄會在10天之后被系統自動清理掉。
解決辦法：
1 重啟項目，系統會自動重新生成該目錄
2 手動創建該目錄
3 在代碼中增加系統默認目錄配置 ，如下：
@Bean
MultipartConfigElement multipartConfigElement() {
MultipartConfigFactory factory = new MultipartConfigFactory();
factory.setLocation("/app/tmp");
return factory.createMultipartConfig();
}