1.FileUploadServlet.java文件，实现上传处理
import java.io.File; import java.io.IOException; import java.io.PrintWriter; import java.text.DecimalFormat; import java.util.Iterator; 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.FileUploadBase.SizeLimitExceededException; import org.apache.commons.fileupload.disk.DiskFileItemFactory; import org.apache.commons.fileupload.servlet.ServletFileUpload; public class FileUploadServlet extends HttpServlet { private static final long serialVersionUID = 1L; public FileUploadServlet() { super(); } protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { this.doPost(request, response); } protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { final long MAX_SIZE = 2048 * 1024 * 1024;// 设置上传文件最大值为2G，可以改为更大 // 允许上传的文件格式的列表 final String[] allowedExt = new String[] { "exe","jpg","DT" }; response.setContentType("text/html"); // 设置字符编码为UTF-8, 统一编码，处理出现乱码问题 response.setCharacterEncoding("UTF-8"); // 实例化一个硬盘文件工厂,用来配置上传组件ServletFileUpload DiskFileItemFactory dfif = new DiskFileItemFactory(); // 用以上工厂实例化上传组件 ServletFileUpload sfu = new ServletFileUpload(dfif); // 设置最大上传大小 sfu.setSizeMax(MAX_SIZE); PrintWriter out = response.getWriter(); // 从request得到所有上传域的列表 List fileList = null; try { fileList = sfu.parseRequest(request); } catch (FileUploadException e) {// 处理文件尺寸过大异常 if (e instanceof SizeLimitExceededException) { out.println("文件尺寸超过规定大小:" + MAX_SIZE + "字节<p />"); out.println("<a href=https://www.jb51.net/article/\"FileUpload.html\" target=https://www.jb51.net/article/\"_top\">返回</a>"); return; } e.printStackTrace(); } // 没有文件上传 if (fileList == null || fileList.size() == 0) { out.println("请选择上传文件<p />"); out.println("<a href=https://www.jb51.net/article/\"FileUpload.html\" target=https://www.jb51.net/article/\"_top\">返回</a>"); return; } //文件大小取两位小数 DecimalFormat digit=new DecimalFormat("0.00"); // 得到所有上传的文件 Iterator fileItr = fileList.iterator(); // 循环处理所有文件 while (fileItr.hasNext()) { FileItem fileItem = null; String path = null; double size = 0; // 得到当前文件 fileItem = (FileItem) fileItr.next(); // 忽略简单form字段而不是上传域的文件域(<input type="text" />等) if (fileItem == null || fileItem.isFormField()) { continue; } // 得到文件的大小，K为单位并保留两位小数 size = (double)fileItem.getSize()/1024; if ("".equals(path) || size == 0) { out.println("<html><head><title>上传处理界面</title></head>"); out.println("请选择上传文件<p />"); out.println("<a href=https://www.jb51.net/article/\"FileUpload.html\" target=https://www.jb51.net/article/\"_top\">返回</a>"); out.println("</html>"); return; } // 得到文件的完整路径 path = fileItem.getName(); // 得到去除路径的文件名 String t_name = path.substring(path.lastIndexOf("\\") + 1); // 得到文件的扩展名(无扩展名时将得到全名) String t_ext = t_name.substring(t_name.lastIndexOf(".") + 1); // 拒绝接受规定文件格式之外的文件类型 int allowFlag = 0; int allowedExtCount = allowedExt.length; for (; allowFlag < allowedExtCount; allowFlag++) { if (allowedExt[allowFlag].equals(t_ext)) break; } if (allowFlag == allowedExtCount) { out.println("<html><head><title>上传处理界面</title></head>"); out.println("请上传以下类型的文件<p />"); for (allowFlag = 0; allowFlag < allowedExtCount; allowFlag++) out.println("*." + allowedExt[allowFlag] + " "); out.println("<p /><a href=https://www.jb51.net/article/\"FileUpload.html\" target=https://www.jb51.net/article/\"_top\">返回</a>"); out.println("</html>"); return; } try { // 保存文件到服务器根目录下 fileItem.write(new File("\\"+t_name)); System.out.println(t_name); out.println("<html><head><title>上传处理界面</title></head>"); out.println("文件名称为：" + path + "<br>"); out.println("文件上传成功， 已保存为: " + t_name + "<br>"+" 文件大小: " + digit.format(size) + "K <p />"); out.println("<a href=https://www.jb51.net/article/\"FileUpload.html\" target=https://www.jb51.net/article/\"_top\">继续上传</a>"); out.println("</html>"); } catch (Exception e) { e.printStackTrace(); } } } }
2.FileUpload.html文件，实现上传页面。