简单操作实现Java jsp servlet文件上传过程解析

2019-11-26 08:30:31

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来源：转载

供稿：网友

实现文件上传的方式

1、进入http://commons.apache.org/proper/commons-fileupload/using.html

2、点击用户指南

3、对着用户指南一步步复制粘贴，并把代码撸成自己想要的样子

补充：记得要将commons-io-2.4.jar和commons-fileupload-1.2.2.jar这两个包放到编译器里面

现成的代码

JSP 前端页面

<%-- Created by IntelliJ IDEA. User: Administrator Date: 2019/10/8 Time: 16:14 To change this template use File | Settings | File Templates.--%><%@ page contentType="text/html;charset=UTF-8" language="java" %><html><head>  <title>作业三第1遍</title></head><body>文件上传注意事项：<br><ol>  <li>提交方式必须是post</li>  <li>enctype="multipart/form-data"是以字节数据的形式提交表单，否则默认是kv形式，只会提交文件名</li>  <li>如果以默认的application/x-www-form-urlencode的方式提交，上传的就不是文件本身</li></ol><%--application/x-www-form-urlencoded 以键值对的方式上传 --%><%-- multipart/form-data 以二进制的方式上传 --%><form action="/work/UploadServlet" method="post" enctype="multipart/form-data">  <input type="text" name="data1" value="data1Value">  <hr>  <input type="text" name="data2" value="data2Value">  <hr>  <input type="file" name="dataFile">  <hr>  <input type="submit" value="上传该表单">  <hr></form></body></html>

Servlet 后台处理页面

package com.bd25;import org.apache.commons.fileupload.FileItem;import org.apache.commons.fileupload.FileItemFactory;import org.apache.commons.fileupload.FileUploadException;import org.apache.commons.fileupload.disk.DiskFileItemFactory;import org.apache.commons.fileupload.servlet.ServletFileUpload;import javax.servlet.ServletException;import javax.servlet.ServletInputStream;import javax.servlet.annotation.WebServlet;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import java.io.File;import java.io.IOException;import java.io.UnsupportedEncodingException;import java.util.Enumeration;import java.util.Iterator;import java.util.List;@WebServlet(name = "UploadServlet", urlPatterns = "/UploadServlet")public class UploadServlet extends HttpServlet {  protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {    //处理中文乱码--已经测试这个要不要无所谓    request.setCharacterEncoding("UTF-8");    //判断是不是传入的一个二进制的流    boolean isMultipart = ServletFileUpload.isMultipartContent(request);    //创建一个简单工厂实例    FileItemFactory factory = new DiskFileItemFactory();    //创建一个新的文件上传处理程序    ServletFileUpload upload = new ServletFileUpload(factory);    //解析request    try {      List<FileItem> fileItems = upload.parseRequest(request);      //处理上传的项目      Iterator iter=fileItems.iterator();      while(iter.hasNext()){        FileItem item = (FileItem) iter.next();        if (item.isFormField()){          //普通域          processFormField(item);        }else{          //文件域 此处注意processUploadFile()方法的参数里面传入request的目的是让下面写文件的时候获取根目录用的          processUploadFile(item,request);        }                }    } catch (FileUploadException e) {      e.printStackTrace();    }    ServletInputStream inputStream = request.getInputStream();    byte[] bs=new byte[1024];    int total=-1;    while ((total=inputStream.read(bs))!=-1){      System.out.print(new String(bs,0,total));    }  }  /**   * 文件域   * @param item   * @param request   */  private void processUploadFile(FileItem item, HttpServletRequest request) {    //获取文件相关信息    String fileName="";    if (!item.isFormField()) {      String fieldName = item.getFieldName();      fileName = item.getName();      String contentType = item.getContentType();      boolean isInMemory = item.isInMemory();      long sizeInBytes = item.getSize();      System.out.println("文件名： "+fileName+" 文件属性："+fieldName+" 文件大小："+sizeInBytes+" 文件类型："+contentType);    }    //以下是转存操作，找到储存文件的根路径    String fileRootPath=request.getServletContext().getRealPath("/WEB-INF/upload");    File dir = new File(fileRootPath);    if (!dir.exists()){      dir.mkdirs();    }    //写文件    File file = new File(fileRootPath+"/"+fileName);    try {      item.write(file);    } catch (Exception e) {      e.printStackTrace();    }  }  /**   * 普通域   * @param item   */  private void processFormField(FileItem item) {    String key = item.getFieldName();    String value = null;    try {      //处理中文乱码      value = item.getString("UTF-8");    } catch (UnsupportedEncodingException e) {      e.printStackTrace();    }    System.out.println(key+"----"+value);  }  protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {  }  @Override  protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {    super.service(req, resp);    System.out.println("刷新....");  }  @Override  public void init() throws ServletException {    super.init();    System.out.println("初始化....");  }}

运行结果

//说明：路径出现的位置就是网页发布的路径