javaweb中文件上传下载示例

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Html代码
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
<script src="common/js/jquery.js" type="text/javascript"></script>
<script src="common/js/ajaxfileupload.js" type="text/javascript"></script>
<script>
/** 利用ajax方式上传文件 **/
function uploadFile(){
$.ajaxFileUpload({
url : 'TestServlet?action=upload',
secureuri : false,
fileElementId : 'fileC',
dataType: 'text',
success : function(data,status){
if(data.indexOf("上传文件失败!")==-1){
var oldFileName = data.split("|")[0];
var newFileName = data.split("|")[1];
var fileListValue = $("#uploadFileList").html();
var obj = $("#uploadFileList");
var content = fileListValue+"<span id='fileList"+newFileName+"'><br/><a href=\"javascript:downLoadFile('"+data+"')\">"+oldFileName+"</a> &nbsp<img src='common/images/X.gif' onClick=\"deleteFile('"+newFileName+"')\" /></span>";
obj.html(content);
}
},
error: function (data, status, e) //相当于java中catch语句块的用法
{
alert("上传文件失败!");
}
});
}
/** 下载文件 **/
function downLoadFile(fileName){
window.location.href = "TestServlet?action=downLoadFile&fileName="+encodeURIComponent(encodeURIComponent(fileName));
}
</script>
</head>
<body>
<form name="frm" id="frm" method="POST" enctype="multipart/form-data">
<input type="file" name="fileC" id="fileC" style="width:400px;height:25px"/>
<input type="button" name="upload" id="upload" value="上传文件" onClick="uploadFile()"/>
<br/><span id="uploadFileList"></span>
</form>
</body>
</html>

java代码

import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Iterator;
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 TestServlet extends HttpServlet {
public TestServlet() {
super();
}
public void destroy() {
super.destroy(); // Just puts "destroy" string in log
}
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doPost(request, response);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html;charset=utf-8");// 设置编码方式，保证返回到前台中文不乱码
request.setCharacterEncoding("UTF-8");// 设置编码方式，保证从前台到后台中文不乱码
response.setCharacterEncoding("UTF-8");
String action = request.getParameter("action");
if (action.equals("upload")) {
upload(request, response);
} else if (action.equals("deleteFile")) {
deleteFile(request, response);
} else if(action.equals("downLoadFile")){
downLoadFile(request, response);
}
}
public void init() throws ServletException {
// Put your code here
}
/**
* 上传文件
*
* @param request
* @param response
* @throws ServletException
* @throws IOException
*/
public void upload(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
String result = "";
try {
result = UpFile(request);
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
result = "上传文件失败!";
}
System.out.println(result);
response.getWriter().print(result);
}
/**
* 删除上传的文件
*
* @param request
* @param response
* @throws ServletException
* @throws IOException
*/
public void deleteFile(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
String result = "";
String fileName = request.getParameter("fileName");
try {
boolean b = false;
b = deleteFileDao(fileName);
if (b) {
result = "删除成功!";
} else {
result = "删除失败!";
}
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
result = "删除文件失败!";
}
response.getWriter().print(result);
}
/**
* 下载文件
* @param request
* @param response
* @throws ServletException
* @throws IOException
*/
public void downLoadFile(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
String fileName = java.net.URLDecoder.decode(request.getParameter("fileName"),"UTF-8");//后台转编码一次成中文
String[] fileNameAll = fileName.split("\\|");
String oldFileName = fileNameAll[0];
String newFileName = fileNameAll[1];
String filePath = this.getServletConfig().getServletContext().getRealPath("/");
File file = new File(filePath + "uploaded\\" + newFileName);
response.setContentType("application/x-msdownload");
response.setContentLength((int) file.length());
response.setHeader("Content-Disposition", "attachment;filename=" + new String(oldFileName.getBytes("GBK"), "ISO8859_1"));//保证另存为文件名为中文
FileInputStream fis = new FileInputStream(file);
BufferedInputStream bis = new BufferedInputStream(fis);
byte[] b = new byte[1024];
long k = 0;
OutputStream out = response.getOutputStream();
while (k < file.length()) {
int j = bis.read(b, 0, 1024);
k += j;
out.write(b, 0, j);
}
out.close();
bis.close();
fis.close();
}
/**
* 上传文件
*
* @param req
* @return
* @throws Exception
*/
public String UpFile(HttpServletRequest req) throws Exception {// 上传文件
// req.setCharacterEncoding("UTF-8");//设置编码方式，让上传的文件（中文）不会出现乱码
String fileName = "";
String filePath = this.getServletConfig().getServletContext()
.getRealPath("/");
File saveDir = new File(filePath + "uploaded");
if (!saveDir.isDirectory()) {
saveDir.mkdir();
}
DiskFileItemFactory dff = new DiskFileItemFactory();// 创建该对象
dff.setRepository(saveDir);// 指定上传文件的临时目录
dff.setSizeThreshold(1024000);// 指定在内存中缓存数据大小,单位为byte
ServletFileUpload sfu = new ServletFileUpload(dff);// 创建该对象
sfu.setSizeMax(50000000);// 指定单个上传文件的最大尺寸
List items = sfu.parseRequest(req);// 解析request //
// 请求,并返回FileItemIterator集合
Iterator iter = items.iterator();
while (iter.hasNext()) {
FileItem fis = (FileItem) iter.next();// 从集合中获得一个文件流
if (!fis.isFormField()) {// 过滤掉表单中非文件域
fileName = fis.getName().substring(
fis.getName().lastIndexOf("\\") + 1);// 获得上传文件的文件名
String hzm = fileName.substring(fileName.indexOf('.'));// 获取文件的后缀名
String nameString = getNewFileName() + hzm;// 新生成的文件名称
fis.write(new File(saveDir + "\\" + nameString));
fileName = fileName + "|" + nameString;
}
}
return fileName;
}
/**
* 删除文件
*
* @param fileName
* @return
*/
public boolean deleteFileDao(String fileName) {
boolean b = false;
String filePath = this.getServletConfig().getServletContext()
.getRealPath("/");
File file = new File(filePath + "uploaded\\" + fileName);
if (file.exists()) {
file.delete();
b = true;
}
return b;
}
/**
* 生成新文件名称（年月日时分秒+二位随机码）
*
* @return
*/
public String getNewFileName() {
String newFileName = "";
Date date = new Date();
SimpleDateFormat simpleDateFormat = new SimpleDateFormat(
"yyyyMMddHHmmss");
newFileName = simpleDateFormat.format(date);
String random = getRandom(2);
return newFileName + random;
}
/**
* 获取n位随机数
*
* @param n
* @return
*/
public String getRandom(int n) {
String randomString = "";
if (n == 1) {
randomString = (int) (Math.random() * 10) + "";
} else {
randomString = getRandom(n - 1) + (int) (Math.random() * 10);
}
return randomString;
}
}

依赖的工具类jar包:commons-fileupload-1.2.1.jar,commons-io-1.3.2.jar

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