在Servlet中实现文件的上传

1,upload.jsp文件的内容如下,就是一个简单的表单:

<form action="/s2sh/FileUploadServlet" method="post"   enctype="multipart/form-data">
Username:<input type="text" name="username"><br>
Password:<input type="text" name="password"><br>
File1:<input type="file" name="file1"><br>
File2:<input type="file" name="file2"><br>
<input type="submit" name="submit">
</form>

2,在web.xml文件中的配置如下:
  <servlet>
    <servlet-name>FileUploadServlet</servlet-name>
    <servlet-class>com.test.servlet.FileUploadServlet</servlet-class>
  </servlet>

  <servlet-mapping>
    <servlet-name>FileUploadServlet</servlet-name>
    <url-pattern>/FileUploadServlet</url-pattern>
  </servlet-mapping>

3,在servlet类中的代码如下:
package com.test.servlet;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.List;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.FileUploadException;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;

public class FileUploadServlet extends HttpServlet {

public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
//请参考apache提供的fileupload和io API.
DiskFileItemFactory factory = new DiskFileItemFactory();

String path = request.getRealPath("/upload");

factory.setSizeThreshold(1024 * 1024);

factory.setRepository(new File(path));

ServletFileUpload upload = new ServletFileUpload(factory);

try {

List<FileItem> list = upload.parseRequest(request);

for(FileItem item : list){

if(item.isFormField()){
String name = item.getFieldName();
String value = item.getString("gbk");
request.setAttribute(name, value);
}else{
String name = item.getFieldName();
String value = item.getName();
int index = value.lastIndexOf("\\");
String fileName = value.substring(index + 1);
request.setAttribute(name, fileName);
//用这一句可以代替下面的io操作
item.write(new File(path,fileName));
// OutputStream os = new FileOutputStream(new File(path,fileName));
// InputStream is = item.getInputStream();
// byte[] buffer = new byte[400];
// int length = 0;
// while((length = is.read(buffer)) > 0){
// os.write(buffer, 0, length);
// }
// os.close();
// is.close();
}
}

} catch (Exception e) {
e.printStackTrace();
}
request.getRequestDispatcher("upload/result.jsp").forward(request, response);
}

}
5,结果页面如下result.jsp:
username;${requestScope.username }<br>
password:${requestScope.password }<br>
file1:${requestScope.file1 }<br>
file2:${requestScope.file2 }<br>

仅供个人学习,感兴趣的人可以参考。

 

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