java FileNotFoundException（是一个目录）
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FileNotFoundException (Is a Directory)
提问by Sandeep Rao
I am currently trying to upload multiple files, and the files are being upload properly into the destination directory. But in the logs it is giving me this error:
我目前正在尝试上传多个文件，并且这些文件正在正确上传到目标目录中。但是在日志中它给了我这个错误：
java.io.FileNotFoundException: /home/sandeep/java_proj/jee_tut/files (Is a directory)
at java.io.FileOutputStream.open(Native Method)
at java.io.FileOutputStream.<init>(FileOutputStream.java:221)
at java.io.FileOutputStream.<init>(FileOutputStream.java:171)
at com.jee.controller.FileProcessing.uploadFiles(FileProcessing.java:35)
at com.jee.controller.View.doPost(View.java:48)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:646)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:501)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:950)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1040)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:607)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:314)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:745)
This is my code for uploading the files:
这是我上传文件的代码：
final String UPLOAD_DIR="files";
String applicationPath="/home/sandeep/java_proj/jee_tut";
String uploadDirPath= applicationPath + File.separator + UPLOAD_DIR;
try{
File fileDir=new File(uploadDirPath);
if(!fileDir.exists()){
fileDir.mkdirs();
}
InputStream inputStream= null;
OutputStream outputStream = null;
try{
for(Part part:request.getParts()){
String fileName=getFileName(part);
File outputPath=new File(uploadDirPath + File.separator + fileName);
inputStream = part.getInputStream();
outputStream = new FileOutputStream(outputPath);
int read = 0;
final byte[] bytes = new byte[1024];
while((read=inputStream.read(bytes)) != -1){
outputStream.write(bytes, 0, read);
}
System.out.println(fileName);
}
}catch(Exception e){
e.printStackTrace();
return "";
}
finally{
if(inputStream != null){
inputStream.close();
}
if(outputStream != null){
outputStream.close();
}
}
return uploadDirPath;
}catch(Exception e){
e.printStackTrace();
return "";
}
As I am new to java, I'm not sure why it is giving me this error. How do I debug this?
由于我是 Java 新手，我不确定为什么会出现此错误。我该如何调试？
回答by Jens
Looks like in some cases filenameis blank or null so File outputPath=new File(uploadDirPath + File.separator + fileName);will be a directory and here new FileOutputStream(outputPath);you try to write to a directory not to a file. So you should check if filenameis not blank.
看起来在某些情况下filename为空或空，因此File outputPath=new File(uploadDirPath + File.separator + fileName);将是一个目录，在这里new FileOutputStream(outputPath);您尝试写入目录而不是文件。所以你应该检查是否filename不为空。
回答by fge
You have many errors in your code. For one, you only close the lastInputStreams and OutputStreams; you should close each of them. The way you do things here, you have a resource leak.
您的代码中有很多错误。一方面，你只关闭最后的InputStreams 和OutputStreams；你应该关闭它们中的每一个。你在这里做事的方式，你有资源泄漏。
Second, this is 2015; therefore drop Fileand use java.nio.file instead; plus, use try-with-resources.
第二，这是2015年；因此删除File并使用 java.nio.file 代替；另外，使用 try-with-resources。
Third: right now you upload in the project directory; don't do that when the application runs "live" on a server, this obviously won't work.
第三：现在你在项目目录中上传；当应用程序在服务器上“实时”运行时，不要这样做，这显然是行不通的。
Sample:
样本：
private static final Path BASEDIR = Paths.get("/path/to/upload/directory");
// in the upload method:
Files.createDirectories(BASEDIR);
String fileName;
Path path;
for (final Part part: request.getParts()) {
fileName = getFileName(part);
if (fileName.isEmpty())
continue;
path = BASEDIR.resolve(fileName);
try (
final InputStream in = part.getInputStream();
) {
Files.copy(in, path, StandardOpenOption.CREATE_NEW);
}
}
回答by Manohar Reddy
This error occured to me because I was using file.mkdirs()with complete fileName .
这个错误发生在我身上，因为我使用的file.mkdirs()是完整的 fileName 。
Suppose your file path is emulated/0/test/images/img.jpg
假设你的文件路径是 emulated/0/test/images/img.jpg
Then remove last part from the path and use file.mkdirs()on result file
然后从路径中删除最后一部分并file.mkdirs()在结果文件上使用
File file=new File("emulated/0/test/images/")
if(!file.exists()){
file.mkdirs();
}
