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

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"%>

<%@taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>

">

">

" type="text/css" rel="stylesheet"/>

">

onmouseover="javascript:this.className='ButtonOver'" onmouseout="javascript:this.className='Button'">

上传所有

onmouseover="javascript:this.className='ButtonOver'" onmouseout="javascript:this.className='Button'">

上传所有

onmouseover="javascript:this.className='ButtonOver'" onmouseout="javascript:this.className='Button'">

取消上传

onmouseover="javascript:this.className='ButtonOver'" onmouseout="javascript:this.className='Button'">

取消上传

js文件

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 mapData = new HashMap();

// 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 items = upload.parseRequest(request);

// 7.对所有请求信息进行判断

Iterator 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 serialVersionUIhttp://D = 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

demo_uploadAndDownload

webAppRootKey

uploadAndDownload

upload

controller.fileHandler.FileUpload

upload

/uploadFile.do

view

controller.fileHandler.FileView

view

/viewFile.do

download

controller.fileHandler.FileDownload

download

/downloadFile.do

delete

controller.fileHandler.FileDelete

delete

/deleteFile

index.html

index.htm

index.jsp

default.html

default.htm

default.jsp

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

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