jsp+servlet实现文件上传与下载功能（jspservlet增删改查 miniui）全程干货

文章摘要

本文介绍了一个JavaServlet实现的文件上传功能，该Servlet继承自HttpServlet，并实现了处理文件上传的逻辑。代码中定义了一个名为UploadAnnexServlet的类，该类通过继承和实现HttpServlet接口，提供了上传文件的功能。该Servlet支持从表单字段直接上传文件和将文件上传到指定目录。在处理请求时，代码通过解析HttpServletRequest中的文件信息，并根据文件类型（表单字段或普通文件）分别处理，最后将处理结果返回给客户端，并重定向到指定页面。代码中还包含异常处理部分，用于处理上传过程中的常见错误情况。

import java.io.File;
import java.io.IOException;
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.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;

public class UploadAnnexServlet extends HttpServlet {

private static String path=””;

public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {

doPost(request, response);
}

public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {

path=this.getServletContext().getRealPath(“/upload”);

try {
DiskFileItemFactory factory=new DiskFileItemFactory();
ServletFileUpload up=new ServletFileUpload(factory);
List<FileItem> ls=up.parseRequest(request);

for (FileItem fileItem : ls) {
if (fileItem.isFormField()) {
String FieldName=fileItem.getFieldName();
//getName()返回的是文件名字普通域没有文件返回NULL
// String Name=fileItem.getName();
String Content=fileItem.getString(“gbk”);
request.setAttribute(FieldName, Content);
} else {

String nm=fileItem.getName().substring(
fileItem.getName().lastIndexOf(“\”) + 1);
File mkr=new File(path, nm);
if (mkr.createNewFile()) {
fileItem.write(mkr);//非常方便的方法
}
request.setAttribute(“result”, “上传文件成功！”);
}
}
} catch (Exception e) {
e.printStackTrace();
request.setAttribute(“result”, “上传失败，请查找原因，重新再试！”);
}
request.getRequestDispatcher(“/pages/admin/annex-manager.jsp”).forward(
request, response);
}

}