即使发生异常（FileNotFoundException（访问被拒绝））之后，文件仍上载

Question

我创建了一个servlet，该servlet可以上传文件，该文件是用户从表单中选择的。

HTML表单片段为：

    <form method="POST" enctype="multipart/form-data" action="UploadFile">
<div class="form-group">
    <label for="inputModuleName">Module Name</label>
    <input type="text" class="form-control" id="inputModuleName" placeholder="Module Name">
</div>
<div class="form-group">
    <label for="exampleInputFile">File input</label>
    <input type="file" id="exampleInputFile" name="fileName">
    <p class="help-block">Only .docx & .pdf files</p>
</div>
    <div class="form-group">
    <label for="inputComment">Comments</label>
    <textarea class="form-control" rows="4" placeholder="Write here..."></textarea>
</div>
<button name="uploadButton" class="btn btn-default">Upload</button>

注意：此处仅是文件类型输入，因为它是测试页。 目前没有其他输入字段被处理。

和Servlet代码是：

    import java.io.*;
    import java.sql.*;

    import javax.servlet.ServletException;
    import javax.servlet.annotation.WebServlet;
    import javax.servlet.annotation.MultipartConfig;
    import javax.servlet.*;
    import javax.servlet.http.*;

    @MultipartConfig(fileSizeThreshold=1024*1024*2, maxFileSize=1024*1024*5)
    public class UploadFile extends HttpServlet {

    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException{
    PrintWriter out = response.getWriter();

    String appPath = request.getServletContext().getRealPath("/");
    String saveDir = getServletContext().getInitParameter("uploaddir");
    String savePath = appPath + saveDir;

    File fileSaveDir = new File(savePath);

    try{
        for(Part part : request.getParts()){
            String fileName = extractFileName(part);
            part.write(savePath + File.separator + fileName);
        }
        out.println("File uploaded!!!");
    }catch(Exception e){
        e.printStackTrace();
    out.println("Error: Can't Upload");
    }
}

private String extractFileName(Part part) {
    String contentDisp = part.getHeader("content-disposition");
    String[] items = contentDisp.split(";");
    for (String s : items) {
        if (s.trim().startsWith("filename")) {
            return s.substring(s.indexOf("=") + 2, s.length()-1);
        }
    }
    return "";
}
}

当我提交表单时，它总是抛出异常，并且在控制台中得到以下输出，但是文件被上载到了文件夹中：

java.io.IOException: java.io.FileNotFoundException: C:\tomcat\webapps\proto1\filesupload (Access is denied)
    at org.apache.catalina.core.ApplicationPart.write(ApplicationPart.java:121)
    at UploadFile.doPost(UploadFile.java:30)
    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:503)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:170)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
    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:421)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1070)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:611)
    at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.doRun(AprEndpoint.java:2466)
    at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.run(AprEndpoint.java:2455)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.lang.Thread.run(Thread.java:745)
    Caused by: java.io.FileNotFoundException: C:\tomcat\webapps\proto1\filesupload (Access is denied)
    at java.io.FileOutputStream.open(Native Method)
    at java.io.FileOutputStream.<init>(FileOutputStream.java:213)
    at java.io.FileOutputStream.<init>(FileOutputStream.java:162)
    at org.apache.tomcat.util.http.fileupload.disk.DiskFileItem.write(DiskFileItem.java:377)
    at org.apache.catalina.core.ApplicationPart.write(ApplicationPart.java:119)
    ... 24 more

如何解决这个问题？

需要考虑的几点：

• 我将Windows 8.1 OS与Apache Tomcat 7服务器一起使用。
• saveFileDir.canRead()和saveFileDir.canWrite()都返回true 。
• 从文件夹的安全设置将权限编辑为“完全修改”。

Answer 1

尝试使用File.separator而不是在路径中放置斜线。这可以确保使用与OS相关的路径分隔符。

这样做很多余，但仍然尝试使用双反斜杠。“ \\\\”。

这是我阅读的链接。

在这里阅读