簡單操作實(shí)現(xiàn)Java jsp servlet文件上傳過程解析

更新時(shí)間：2019年10月09日 09:03:21 作者：小龍_T無限

這篇文章主要介紹了簡單操作實(shí)現(xiàn)Java jsp servlet文件上傳過程解析,文中通過示例代碼介紹的非常詳細(xì)，對(duì)大家的學(xué)習(xí)或者工作具有一定的參考學(xué)習(xí)價(jià)值,需要的朋友可以參考下

實(shí)現(xiàn)文件上傳的方式

1、進(jìn)入http://commons.apache.org/proper/commons-fileupload/using.html

2、點(diǎn)擊用戶指南

3、對(duì)著用戶指南一步步復(fù)制粘貼，并把代碼擼成自己想要的樣子

補(bǔ)充：記得要將commons-io-2.4.jar和commons-fileupload-1.2.2.jar這兩個(gè)包放到編譯器里面

現(xiàn)成的代碼

JSP 前端頁面

<%--
 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>作業(yè)三第1遍</title>
</head>
<body>
文件上傳注意事項(xiàng)：<br>
<ol>
  <li>提交方式必須是post</li>
  <li>enctype="multipart/form-data"是以字節(jié)數(shù)據(jù)的形式提交表單，否則默認(rèn)是kv形式，只會(huì)提交文件名</li>
  <li>如果以默認(rèn)的application/x-www-form-urlencode的方式提交，上傳的就不是文件本身</li>
</ol>
<%--application/x-www-form-urlencoded 以鍵值對(duì)的方式上傳 --%>
<%-- multipart/form-data 以二進(jìn)制的方式上傳 --%>
<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="上傳該表單">
  <hr>
</form>


</body>
</html>

Servlet 后臺(tái)處理頁面

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 {
    //處理中文亂碼--已經(jīng)測(cè)試這個(gè)要不要無所謂
    request.setCharacterEncoding("UTF-8");

    //判斷是不是傳入的一個(gè)二進(jìn)制的流
    boolean isMultipart = ServletFileUpload.isMultipartContent(request);
    //創(chuàng)建一個(gè)簡單工廠實(shí)例
    FileItemFactory factory = new DiskFileItemFactory();
    //創(chuàng)建一個(gè)新的文件上傳處理程序
    ServletFileUpload upload = new ServletFileUpload(factory);
    //解析request
    try {
      List<FileItem> fileItems = upload.parseRequest(request);
      //處理上傳的項(xiàng)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 此處注意processUploadFile()方法的參數(shù)里面?zhèn)魅雛equest的目的是讓下面寫文件的時(shí)候獲取根目錄用的
          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) {
    //獲取文件相關(guān)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+" 文件屬性："+fieldName+" 文件大?。?+sizeInBytes+" 文件類型："+contentType);
    }
    //以下是轉(zhuǎn)存操作，找到儲(chǔ)存文件的根路徑
    String fileRootPath=request.getServletContext().getRealPath("/WEB-INF/upload");
    File dir = new File(fileRootPath);
    if (!dir.exists()){
      dir.mkdirs();
    }
    //寫文件
    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 {
      //處理中文亂碼
      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....");
  }
}

運(yùn)行結(jié)果

//說明：路徑出現(xiàn)的位置就是網(wǎng)頁發(fā)布的路徑