位置：首页>> 软件编程>> java编程>> servlet实现文件上传、预览、下载、删除功能

servlet实现文件上传、预览、下载、删除功能

作者：Marydon　　发布时间：2023-11-16 21:52:48　

标签：servlet,文件上传,预览,下载,删除

servlet实现文件上传，预览，下载和删除，供大家参考，具体内容如下

一、准备工作：

1.1 文件上传插件：uploadify；

1.2 文件上传所需jar包：commons-fileupload-1.3.1.jar和commons-io-2.2.jar

1.3 将数据转成JSON对象需要jar包：commons-beanutils-1.8.3.jar、commons-collections-3.2.1.jar、commons-lang-2.6.jar、commons-logging-1.1.3.jar、ezmorph-1.0.6.jar和json-lib-2.4-jdk15.jar

1.4 开发工具：我用的是Eclipse，随意

1.5 目录结构

需要注意的是：变更uploadify.css文件中的取消文件上传图片的路径

.uploadify-queue-item .cancel a {
background: url('../images/uploadify-cancel.png') 0 0 no-repeat;
float: right;
height: 16px;
text-indent: -9999px;
width: 16px;
}

二、代码展示

2.1 客户端代码设计

JSP部分

<％@ page language="java" import="java.util.*" pageEncoding="UTF-8"％>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>演示-操作文件</title>
<％@taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" ％>
<script type="text/javascript" src="<c:url value="/js/jquery-1.11.2.min.js"/>"></script>
<script type="text/javascript" src="<c:url value="/uploadify/js/jquery.uploadify-3.2.1.min.js"/>"></script>
<link href="<c:url value=" rel="external nofollow" /uploadify/css/uploadify.css"/>" type="text/css" rel="stylesheet"/>
<script type="text/javascript">var baseUrl = '<％=request.getContextPath()％>';</script>
<script type="text/javascript" src="<c:url value="/index.js"/>"></script>
<style type="text/css">
/* 上传、取消上传按钮style start */
.Button {
width: 80px;
margin: 3px 1px 0 5px;
padding: 0 10px;
background-color: #16a0d3;
border: none;
display: inline-block;
font-family: "Microsoft Yahei";
font-size: 14px;
cursor: pointer;
height: 30px;
line-height: 30px;
color: #FFF;
border-radius: 5px;
text-decoration:none;
text-align:center;
}

.ButtonOver {
width: 80px;
margin: 3px 1px 0 5px;
padding: 0 10px;
background-color: #117ea6;
border: none;
display: inline-block;
font-family: "Microsoft Yahei";
font-size: 14px;
cursor: pointer;
height: 30px;
line-height: 30px;
color: #FFF;
border-radius: 5px;
text-decoration:none;
text-align:center;
}
/* end 上传、取消上传按钮style */
</style>
</head>
<body>

<div id="file_upload"></div>
<div id="ctrlUpload" style="display:none;">
<a href="javascript:;" rel="external nofollow" rel="external nofollow" rel="external nofollow" onclick="$('#file_upload').uploadify('upload', '*');" class="Button"
onmouseover="javascript:this.className='ButtonOver'" onmouseout="javascript:this.className='Button'">
上传所有
</a>
<a href="javascript:;" rel="external nofollow" rel="external nofollow" rel="external nofollow" onclick="$('#file_upload').uploadify('cancel', '*');$('#ctrlUpload').hide();" class="Button"
onmouseover="javascript:this.className='ButtonOver'" onmouseout="javascript:this.className='Button'">
取消上传
</a>
</div>
<table border=1 style="border-collapse: collapse;" id="tableFiles">
<thead>
<th>序号</th>
<th>文件名</th>
<th>文件预览</th>
<th>文件下载</th>
<th>文件删除</th>
</thead>
<tbody></tbody>
</table>
</body>
</html>

js文件

var operateFile = new OperateFile();
window.onload = function() {
operateFile.init();

}

/**
* 对文件进行操作
* @returns
*/
function OperateFile() {
var object = this;

/**
* 初始化操作：
*/
this.init = function() {
// 队列中的文件数
var selectedCount = 0;
$('#file_upload').uploadify({
'method' : 'get',// 默认值post，设置成get是为了向后台传递自定义的参数
'auto' : false,// 设置为true当选择文件后就直接上传了，为false需要点击上传按钮才上传。默认值为TRUE
'buttonText' : '添加文件',// 按钮文本
'fileTypeExts' : '*.gif; *.jpg; *.png;*.pdf;*.zip;',// 限制上传文件类型，默认值没有限制（*.*）
'fileTypeDesc' : '请选择gif jpg png pdf zip类型的文件',// 这个属性值必须设置fileTypeExts属性后才有效，用来设置选择文件对话框中的提示文本，默认值：All Files
'swf' : baseUrl + '/uploadify/flash/uploadify.swf', // flash文件路径（帮助我们与后端交互数据）
'uploader' : baseUrl + '/uploadFile.do' , // 处理文件上传请求地址
'formData' : {'param1':'测试文件上传'},// 请求参数：上传每个文件的同时提交到服务器的额外数据
'onDialogClose' : function(queueData) {
// 获取该队列中有多少个要上传的文件
var queueSize = $('#file_upload-queue').children('div').length;
if (queueSize > 0) {
$('#ctrlUpload').show();
}
},
'onUploadSuccess' : function(file, data, response) {// 上传成功
// 将josn字符串转换成JSON对象
data = eval('(' + data + ')');
// 获取页面上文件展示table 有多少行
var rowsLength = $('#tableFiles')[0].rows.length;
// 设置查看文件所需参数
var param = "fileName=" + data.fileName;
// 查看文件请求地址
var viewUrl = baseUrl + '/viewFile.do?' + param;
// 下载文件请求地址
var downloadUrl = baseUrl + '/downloadFile.do?' + param;

// 拼接一行tr
var trTemplate = '<tr>'
+ '<td>'
+ rowsLength
+ '</td>'
+ '<td>'
+ file.name // 仍展示原文件名
+ '</td>'
+ '<td>'
+ '<a href="' + viewUrl + '" rel="external nofollow" target="_blank">点击预览</a>'
+ '<input type="hidden" name="imgAddress" value="' + data.fileName + '"/>'
+ '</td>'
+ '<td>'
+ '<a href="' + downloadUrl + '" rel="external nofollow" >点击下载</a>'
+ '</td>'
+ '<td>'
+ '<a href="javascript:;" rel="external nofollow" rel="external nofollow" rel="external nofollow" onclick="operateFile.deleteFile(\'' + data.fileName + '\',' + rowsLength +');">点击删除</a>'
+ '</td>'
+'</tr>';
$('#tableFiles').append(trTemplate);
},
'onUploadError' : function(file, errorCode, errorMsg, errorString) {// 上传失败

}
});

}

/**
* 删除文件
* @param 文件名
*/
this.deleteFile = function(fileName,rowIndex) {
// 设置删除文件所需参数
var param = "fileName=" + fileName;
// 删除文件请求地址
var deleteUrl = baseUrl + '/deleteFile.do?' + param;
$.get(
deleteUrl,
function(msg) {
alert(msg);
if ("删除失败！" != msg) {
// 删除该行记录
$('#tableFiles')[0].deleteRow(rowIndex);
}
}
);

}

}

2.2 服务器端代码设计

文件上传代码（FileUpload.javae文件）

package controller.fileHandler;

import java.io.File;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import javax.servlet.ServletContext;
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.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
import net.sf.json.JSONObject;

public class FileUpload extends HttpServlet {
private static final long serialVersionUID = 1L;

protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
this.doPost(request, response);
}

/**
* 处理文件上传的post
* @precaution 下方的类名出自包import org.apache.commons.fileupload.*
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
// 1.设置参数编码
request.setCharacterEncoding("UTF-8");
// 设置响应数据字符集
response.setCharacterEncoding("UTF-8");
// 设置响应数据格式
// response.setContentType("application/json; charset=UTF-8");
PrintWriter out = response.getWriter();
// 2.创建文件上传处理工厂
DiskFileItemFactory factory = new DiskFileItemFactory();
// 3.设置临时文件存放地点
// 3.1获取当前web应用程序对象（WEB容器在启动时，它会为每个WEB应用程序都创建一个对应的ServletContext对象，它代表当前web应用）
ServletContext servletContext = this.getServletConfig().getServletContext();
// 3.2获取服务器的临时目录（tomcat、WebLogic）
// D:\ProgramFiles(x86)\APACHE\TOMCAT\apache-tomcat-7.0.40-x86\work\Catalina\localhost\demo
File repository = (File) servletContext.getAttribute("javax.servlet.context.tempdir");
// 3.3临时文件将会存储在该目录下
factory.setRepository(repository);
// 4.创建文件上传处理器
ServletFileUpload upload = new ServletFileUpload(factory);
// 5.判断请求类型是否为文件上传类型
boolean multipartContent = upload.isMultipartContent(request);

Map<String, String> mapData = new HashMap<String, String>();
// 返回信息
String msg = "";
// 错误信息
String errorMsg = "";
// 文件名
String fileName = "";
if (multipartContent) {
try {
// 获取请求参数
String param = request.getParameter("param1");
System.out.println(param);
// 6.解析请求信息
List<FileItem> items = upload.parseRequest(request);

// 7.对所有请求信息进行判断
Iterator<FileItem> iter = items.iterator();
while (iter.hasNext()) {
FileItem item = iter.next();
// 信息为文件格式
if (!item.isFormField()) {
fileName = processUploadedFile(param, item);
msg = "上传成功！";
}
}
} catch (FileUploadException e) {
e.printStackTrace();
msg = "上传失败！";
errorMsg = e.getMessage();
}

} else {
msg = "form表单类型不是multipart/form-data，无法上传！";
}

mapData.put("msg", msg);
mapData.put("errorMsg", errorMsg);
mapData.put("fileName", fileName);
// 将Map转成JSON
JSONObject jsonData = JSONObject.fromObject(mapData);
// 返回客户端信息
out.print(jsonData.toString());
}

/**
* 处理上传的文件
* @param ORG_ID
* @param order
* @param item
*/
@SuppressWarnings("unused")
private String processUploadedFile(String param, FileItem item) {
// Process a file upload
String fieldName = item.getFieldName();// 默认值为Filedata
// 获取文件名
String fileName = item.getName();
// 内容类型：application/octet-stream
String contentType = item.getContentType();
boolean isInMemory = item.isInMemory();
// 获取文件大小
long sizeInBytes = item.getSize();
// 1.指定文件上传的根路径
String path = this.getServletContext().getRealPath("/WEB-INF/uploadFiles");
// 2.路径构成：/uploadfile/fileName
// TODO 可以自定义文件存放路径
// 3.根据路径批量创建文件夹
File fileDirectories = new File(path);
// 目录不存在时，再创建
if (!fileDirectories.exists()) {
fileDirectories.mkdirs();// 所有的文件夹都创建成功才返回TRUE
}
// 4.文件名格式校验（文件名中不能包含#号）
int index = fileName.indexOf("#");
if (index > -1) {
fileName = fileName.replace('#', '_');
}
// TODO 可以对文件名进行重命名
// 5.在指定路径下创建指定名称的文件
File uploadedFile = new File(path + "/" + fileName);
// 6.判断该文件是否已存在
if (!uploadedFile.exists()) {
try {
// 使用了这个方法写入文件，临时文件会被系统自动删除
item.write(uploadedFile);
} catch (Exception e) {
e.printStackTrace();
}
}
// 返回重名后的文件名
return fileName;
}

/**
* 处理信息为普通的格式
* @param item
*/
private void processFormField(FileItem item) {
// Process a regular form field
if (item.isFormField()) {
String name = item.getFieldName();
String value = item.getString();
}
}
}

文件查看代码（FileView.java文件）

package controller.fileHandler;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class FileView extends HttpServlet {
private static final long serialVersionUID = 1L;

// 设定输出的类型
private static final String GIF = "image/gif;charset=UTF-8";
private static final String JPG = "image/jpeg;charset=UTF-8";
private static final String PNG = "image/png;charset=UTF-8";
private static final String PDF = "application/pdf;charset=UTF-8";
private static final String ZIP = "application/zip;charset=UTF-8";

protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
this.doPost(request, response);
}

/**
* 处理文件查看的post
* @throws IOException
* @precaution 下方的类名出自包import org.apache.commons.fileupload.*
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
// 文件流
InputStream is = null;
// 输入缓冲流
BufferedInputStream bis = null;
// 得到输出流
OutputStream output = null;
// 输出缓冲流
BufferedOutputStream bos = null;
// 1.设置参数编码
request.setCharacterEncoding("UTF-8");
// 2.设置响应数据字符集
response.setCharacterEncoding("UTF-8");
// 3.获取客户端请求参数：文件名
String fileName = request.getParameter("fileName");
// 4.重置response
response.reset();
// 5.设置响应数据格式
if (fileName.endsWith(".gif")) {
response.setContentType(GIF);
} else if (fileName.endsWith(".jpg")) {
response.setContentType(JPG);
} else if (fileName.endsWith(".png")) {
response.setContentType(PNG);
} else if (fileName.endsWith(".pdf")) {
response.setContentType(PDF);
} else if (fileName.endsWith(".gif")) {
response.setContentType(GIF);
} else if (fileName.endsWith(".zip")) {
response.setContentType(ZIP);
}

String filePath = "WEB-INF/uploadFiles/" + fileName;
// 获取当前web应用程序
ServletContext webApp = this.getServletContext();
// 6.获取指定文件上传的真实路径
filePath = webApp.getRealPath(filePath);
// 7.读取目标文件，通过response将目标文件写到客户端
is = new FileInputStream(filePath);
bis = new BufferedInputStream(is);
output = response.getOutputStream();
bos = new BufferedOutputStream(output);
byte data[] = new byte[1024];// 缓冲字节数
int size = bis.read(data);
while (size != -1) {
bos.write(data, 0, size);
size = bis.read(data);
}

// 关闭流
bis.close();
bos.flush();// 清空输出缓冲流
bos.close();
output.close();
}

}

文件下载代码（FileDownload.java文件）

package controller.fileHandler;

import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class FileDownload extends HttpServlet {
private static final long serialVersionUID = 1L;

protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
this.doPost(request, response);
}

/**
* 处理文件下载的post
* @throws IOException
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
// 1.设置参数编码
request.setCharacterEncoding("UTF-8");
// 设置响应数据字符集
response.setCharacterEncoding("UTF-8");
// 1.获得请求文件名
String fileName = request.getParameter("fileName");
// 2.设置文件MIME类型（指定要返回内容的类型）
response.setContentType(getServletContext().getMimeType(fileName));
// 3.设置Content-Disposition（指定下载该文件时的文件名）
response.setHeader("content-disposition", "attachment;filename=" + fileName);
// 4.读取目标文件，通过response将目标文件写到客户端
// 4.1 获取目标文件的绝对路径
String filePath = "WEB-INF/uploadFiles/" + fileName;
filePath = this.getServletContext().getRealPath(filePath);
// 4.2 读取文件
InputStream in = new FileInputStream(filePath);
// 4.3 输出文件
OutputStream out = response.getOutputStream();
// 写文件
int n;
while ((n = in.read()) != -1) {
out.write(n);
}

in.close();
out.close();
}

}

文件删除代码（FileDelete.java文件）

package controller.fileHandler;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class FileDelete extends HttpServlet {
private static final long serialVersionUID = 1L;

protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
this.doPost(request, response);
}

/**
* 处理文件下载的post
* @throws IOException
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
// 1.设置参数编码
request.setCharacterEncoding("UTF-8");
// 设置响应数据字符集
response.setCharacterEncoding("UTF-8");
// 2.获得请求文件名
String fileName = request.getParameter("fileName");
// 3.获取该文件所在路径
String filePath = "WEB-INF/uploadFiles/" + fileName;
filePath = this.getServletContext().getRealPath(filePath);
// 4.在指定路径下创建指定名称的文件
File deleteFile = new File(filePath);
boolean flag = false;
String msg = "";
// 5.判断该文件是否已存在
if (deleteFile.exists()) {
flag = deleteFile.delete();
if (flag) {
msg = "删除成功！";
} else {
msg = "删除失败！";
}
} else {
msg = "该文件不存在！";
}

// 6.返回客户端操作信息
response.getWriter().print(msg);
}

}

web.xml代码

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5">
<display-name>demo_uploadAndDownload</display-name>
<context-param>
<param-name>webAppRootKey</param-name>
<param-value>uploadAndDownload</param-value>
</context-param>


<servlet>
<servlet-name>upload</servlet-name>

<servlet-class>controller.fileHandler.FileUpload</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>upload</servlet-name>

<url-pattern>/uploadFile.do</url-pattern>
</servlet-mapping>


<servlet>
<servlet-name>view</servlet-name>

<servlet-class>controller.fileHandler.FileView</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>view</servlet-name>

<url-pattern>/viewFile.do</url-pattern>
</servlet-mapping>


<servlet>
<servlet-name>download</servlet-name>

<servlet-class>controller.fileHandler.FileDownload</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>download</servlet-name>

<url-pattern>/downloadFile.do</url-pattern>
</servlet-mapping>


<servlet>
<servlet-name>delete</servlet-name>

<servlet-class>controller.fileHandler.FileDelete</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>delete</servlet-name>

<url-pattern>/deleteFile</url-pattern>
</servlet-mapping>

<welcome-file-list>
<welcome-file>index.html</welcome-file>
<welcome-file>index.htm</welcome-file>
<welcome-file>index.jsp</welcome-file>
<welcome-file>default.html</welcome-file>
<welcome-file>default.htm</welcome-file>
<welcome-file>default.jsp</welcome-file>
</welcome-file-list>
</web-app>

2.3 代码优化

处理文件查看（FileView.java），设置响应文件类型，可以用下面这句话替换

response.setContentType(getServletContext().getMimeType(fileName) + ";charset=UTF-8");

三、效果展示

来源：http://www.cnblogs.com/Marydon20170307/p/7472294.html

投稿

servlet实现文件上传、预览、下载、删除功能

猜你喜欢