ajax servlet上传文件

来源：互联网发布：JAVA登录设计编辑：程序博客网时间：2024/05/22 05:13

Java代码

package com.wang;import java.io.File;import java.io.IOException;import java.io.PrintWriter;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.disk.DiskFileItemFactory;import org.apache.commons.fileupload.servlet.ServletFileUpload;/** * Servlet implementation class UploadServlet */@WebServlet("/UploadServlet")public class UploadServlet extends HttpServlet {private static final long serialVersionUID = 1L;// 上传文件存储目录private static final String UPLOAD_DIRECTORY = "upload";// 上传配置private static final int MEMORY_THRESHOLD = 1024 * 1024 * 3; // 3MBprivate static final int MAX_FILE_SIZE = 1024 * 1024 * 40; // 40MBprivate static final int MAX_REQUEST_SIZE = 1024 * 1024 * 50; // 50MB/** * 上传数据及保存文件 */protected void doPost(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException {// 检测是否为多媒体上传if (!ServletFileUpload.isMultipartContent(request)) {// 如果不是则停止PrintWriter writer = response.getWriter();writer.println("Error: 表单必须包含 enctype=multipart/form-data");writer.flush();return;}// 配置上传参数DiskFileItemFactory factory = new DiskFileItemFactory();// 设置内存临界值 - 超过后将产生临时文件并存储于临时目录中factory.setSizeThreshold(MEMORY_THRESHOLD);// 设置临时存储目录factory.setRepository(new File(System.getProperty("java.io.tmpdir")));ServletFileUpload upload = new ServletFileUpload(factory);// 设置最大文件上传值upload.setFileSizeMax(MAX_FILE_SIZE);// 设置最大请求值 (包含文件和表单数据)upload.setSizeMax(MAX_REQUEST_SIZE);// 构造临时路径来存储上传的文件// 这个路径相对当前应用的目录String uploadPath = getServletContext().getRealPath("./")+ File.separator + UPLOAD_DIRECTORY;// 如果目录不存在则创建File uploadDir = new File(uploadPath);if (!uploadDir.exists()) {uploadDir.mkdir();}try {// 解析请求的内容提取文件数据@SuppressWarnings("unchecked")List<FileItem> formItems = upload.parseRequest(request);if (formItems != null && formItems.size() > 0) {// 迭代表单数据for (FileItem item : formItems) {// 处理不在表单中的字段if (!item.isFormField()) {String fileName = new File(item.getName()).getName();String filePath = uploadPath + File.separator+ fileName;File storeFile = new File(filePath);// 在控制台输出文件的上传路径System.out.println(filePath);// 保存文件到硬盘item.write(storeFile);request.setAttribute("message", "文件上传成功!");}}}} catch (Exception ex) {request.setAttribute("message", "错误信息: " + ex.getMessage());}// 跳转到 message.jspPrintWriter out = response.getWriter();out.print("success");out.flush();out.close();}}

html代码

<!DOCTYPE html><html><head><title>upload.html</title><meta name="keywords" content="keyword1,keyword2,keyword3"><meta name="description" content="this is my page"><meta name="content-type" content="text/html; charset=UTF-8"><!--<link rel="stylesheet" type="text/css" href="./styles.css">--></head><body><form id="uploadForm" enctype="multipart/form-data"><input id="file" type="file" name="file" /><button id="upload" type="button">upload</button></form></body><script type="text/javascript"src="http://apps.bdimg.com/libs/jquery/2.1.1/jquery.min.js"></script><script type="text/javascript">$("#upload").click(function() {$.ajax({url:'http://127.0.0.1:8080/u/UploadServlet',type:'POST',cache:false,data:new FormData($('#uploadForm')[0]),processData : false,contentType : false}).done(function(res) {alert(res);}).fail(function(res) {alert(res);});});</script></html>

一：commons-upload在解析request的inputstream会首先获取boundary，这里面记录着文件流的起始和结束位置。

0 0