Servlet利用Commons FileUpload实现文件上传

来源：互联网发布：数据库关系模型举例编辑：程序博客网时间：2024/05/16 23:53

详情请参考Commons FileUpload官网

The Commons FileUpload package makes it easy to add robust, high-performance, file upload capability to your servlets and web applications.

要想利用Commons FileUpload实现文件上传功能，可以参考官网的“User guide”。简而言之，需要一个Form表单提交文件上传请求，然后在后台通过servlet等技术使用Commons FileUpload来实现文件上传功能。如果需要实现上传进度条功能，则还需要实现ProgerssListener。

示例如下：

FileUploadForm.jsp 利用Form表单提交一个上传文件的请求

<%@ page language="java" contentType="text/html; charset=UTF-8"    pageEncoding="UTF-8"%><!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><title>文件上传</title></head><body><form action="../FileUpload" method="post" enctype="multipart/form-data" name="book"><table><tr><th colspan="2" align="center">录入书籍信息</th></tr><tr><td>书名：</td><td><input type="text" name="bookname" /></td></tr><tr><td>封面：</td><td><input type="file" name="cover" /></td></tr><tr><td>作者：</td><td><input type="text" name="author" /></td></tr><tr><td colspan="2"><input type="submit" value="提交" /></td></tr></table></form></body></html>

FileUpload.java 通过servlet使用Commons FileUpload实现文件上传功能

package fileupload;import java.io.File;import java.io.IOException;import java.util.Iterator;import java.util.List;import javax.servlet.ServletException;import javax.servlet.annotation.WebServlet;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;/** * Servlet implementation class FileUpload */@WebServlet("/FileUpload")public class FileUpload extends HttpServlet {private static final long serialVersionUID = 1L;           /**     * @see HttpServlet#HttpServlet()     */    public FileUpload() {        super();        // TODO Auto-generated constructor stub    }/** * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response) */protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {// TODO Auto-generated method stub// Check that we have a file upload requestssboolean isMultipart = ServletFileUpload.isMultipartContent(request);if (!isMultipart) {return;}// Create a factory for disk-based file itemsDiskFileItemFactory factory = new DiskFileItemFactory();// Set factory constraintsxfactory.setSizeThreshold(1024);//yourMaxMemorySizefactory.setRepository(new File("E:/Downloads/tmp"));//yourTempDirectory// Create a new file upload handlerServletFileUpload upload = new ServletFileUpload(factory);//setProgressListenerupload.setProgressListener(new FileUploadProgressListener());// Parse the requestList items = null;try {items = upload.parseRequest(request);} catch (FileUploadException e1) {// TODO Auto-generated catch blocke1.printStackTrace();}// Process the uploaded itemsIterator iter = items.iterator();while (iter.hasNext()) {FileItem item = (FileItem)iter.next();//整个表单的所有域都会被解析，要先判断一下是普通表单域还是文件上传域if (item.isFormField()) {String name = item.getFieldName();String value = item.getString();System.out.println(name + ":" + value);} else {String fieldName = item.getFieldName();String fileName = item.getName();String contentType = item.getContentType();boolean isInMem = item.isInMemory();long sizeInBytes = item.getSize();System.out.println(fieldName + ":" + fileName);System.out.println("类型：" + contentType);System.out.println("是否在内在：" + isInMem);System.out.println("文件大小" + sizeInBytes);File uploadedFile = new File("E:/Downloads/upload/" + fileName);try {item.write(uploadedFile);} catch (Exception e) {// TODO Auto-generated catch blocke.printStackTrace();}}}}/** * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response) */protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {// TODO Auto-generated method stubthis.doGet(request, response);}}

FileUploadProgressListener.java 实现进度条监听器

package fileupload;import org.apache.commons.fileupload.ProgressListener;public class FileUploadProgressListener implements ProgressListener {public FileUploadProgressListener() {super();// TODO Auto-generated constructor stubSystem.out.println("Progress Listened!");}@Overridepublic void update(long pBytesRead, long pContentLength, int pItems) {// TODO Auto-generated method stubSystem.out.println("现在已经处理了" + pBytesRead+ "数据，总数据量" + pContentLength+ "正在处理" + pItems);}}