JSP的文件上传处理

Jerry Wang

发布于 2020-07-21 13:08:36

7.3K1

发布于 2020-07-21 13:08:36

这个例子展示了如何使用JSP将用户指定的本地文件上传到服务器某个目录下面。

首先是文件上传的用户界面：

<html>
<head>
<title>File Uploading Form</title>
</head>
<body>
<h3>File Upload:</h3>
Select a file to upload: <br />
<form action="UploadServlet.jsp" method="post"
                        enctype="multipart/form-data">
<input type="file" name="file" size="50" />
<br />
<input type="submit" value="Upload File" />
</form>
</body>
</html>

界面如下：

UploadServlet.jsp的源代码：

<%@ page import="java.io.*,java.util.*, javax.servlet.*" %>
<%@ page import="javax.servlet.http.*" %>
<%@ page import="org.apache.commons.fileupload.*" %>
<%@ page import="org.apache.commons.fileupload.disk.*" %>
<%@ page import="org.apache.commons.fileupload.servlet.*" %>
<%@ page import="org.apache.commons.io.output.*" %>

<%
	System.out.println("my file upload jsp file called!");
   File file ;
   int maxFileSize = 5000 * 1024;
   int maxMemSize = 5000 * 1024;
   ServletContext context = pageContext.getServletContext();
   String filePath = context.getInitParameter("file-upload");

   String contentType = request.getContentType();
   if ((contentType.indexOf("multipart/form-data") >= 0)) {

      DiskFileItemFactory factory = new DiskFileItemFactory();

      factory.setSizeThreshold(maxMemSize);

      factory.setRepository(new File("c:\\temp"));

      ServletFileUpload upload = new ServletFileUpload(factory);

      upload.setSizeMax( maxFileSize );
      try{ 

         List fileItems = upload.parseRequest(request);


         Iterator i = fileItems.iterator();

         out.println("<html>");
         out.println("<head>");
         out.println("<title>JSP File upload</title>");  
         out.println("</head>");
         out.println("<body>");
         while ( i.hasNext () ) 
         {
            FileItem fi = (FileItem)i.next();
            if ( !fi.isFormField () )	
            {
            String fieldName = fi.getFieldName();
            String fileName = fi.getName();
            boolean isInMemory = fi.isInMemory();
            long sizeInBytes = fi.getSize();

            if( fileName.lastIndexOf("\\") >= 0 ){
            file = new File( filePath , 
            fileName.substring( fileName.lastIndexOf("\\"))) ;
            }else{
            file = new File( filePath ,
            fileName.substring(fileName.lastIndexOf("\\")+1)) ;
            }
            fi.write( file ) ;
            out.println("Uploaded Filename: " + filePath + 
            fileName + "<br>");
            }
         }
         out.println("</body>");
         out.println("</html>");
      }catch(Exception ex) {
         System.out.println(ex);
      }
   }else{
      out.println("<html>");
      out.println("<head>");
      out.println("<title>Servlet upload</title>");  
      out.println("</head>");
      out.println("<body>");
      out.println("<p>No file uploaded</p>"); 
      out.println("</body>");
      out.println("</html>");
   }
%>

web.xml的内容：

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xmlns="http://java.sun.com/xml/ns/javaee"
	xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
	id="WebApp_ID" version="3.0">
	<display-name>jerryjsp</display-name>
	<welcome-file-list>
		<welcome-file>index.html</welcome-file>
		<welcome-file>index.htm</welcome-file>
		<welcome-file>index.jsp</welcome-file>
		<welcome-file>default.html</welcome-file>
		<welcome-file>default.htm</welcome-file>
		<welcome-file>default.jsp</welcome-file>
	</welcome-file-list>
	
	  
<context-param> 
    <description>File Upload Position</description> 
    <param-name>file-upload</param-name> 
    <param-value>
         c:\temp
     </param-value> 
</context-param>
</web-app>

用Choose File选中一个本地文件，然后点击Upload File进行上传：