jsp+servlet实现文件上传与下载功能

本文实例为大家分享了jsp servlet实现文件上传与下载的具体代码，供大家参考，具体内容如下

上传：

需要导入两个包：commons-fileupload-1.2.1.jar,commons-io-1.4.jar

import java.io.File;
import java.io.IOException;
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;

/**
* 上传附件
* @author new
*
*/
public class UploadAnnexServlet extends HttpServlet {

private static String path = \”\”;

public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {

doPost(request, response);
}

/*
* post处理
* (non-Javadoc)
* @see javax.servlet.http.HttpServlet#doPost(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse)
*/
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {

path = this.getServletContext().getRealPath(\”/upload\”);

try {
DiskFileItemFactory factory = new DiskFileItemFactory();
ServletFileUpload up = new ServletFileUpload(factory);
List<FileItem> ls = up.parseRequest(request);

for (FileItem fileItem : ls) {
if (fileItem.isFormField()) {
String FieldName = fileItem.getFieldName();
//getName()返回的是文件名字普通域没有文件返回NULL
// String Name = fileItem.getName();
String Content = fileItem.getString(\”gbk\”);
request.setAttribute(FieldName, Content);
} else {

String nm = fileItem.getName().substring(
fileItem.getName().lastIndexOf(\”\\\\\”) + 1);
File mkr = new File(path, nm);
if (mkr.createNewFile()) {
fileItem.write(mkr);//非常方便的方法
}
request.setAttribute(\”result\”, \”上传文件成功！\”);
}
}
} catch (Exception e) {
e.printStackTrace();
request.setAttribute(\”result\”, \”上传失败，请查找原因，重新再试！\”);
}
request.getRequestDispatcher(\”/pages/admin/annex-manager.jsp\”).forward(
request, response);
}

}

下载（i/o流）无需导包：

import java.io.IOException;
import java.net.URLEncoder;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
* 下载文件
* @author
*
*/
public class DownloadFilesServlet extends HttpServlet {

/**
*
*/
private static final long serialVersionUID = 8594448765428224944L;

public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {

doPost(request, response);
}

/*
* 处理请求
* (non-Javadoc)
* @see javax.servlet.http.HttpServlet#doPost(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse)
*/
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {

String name = request.getParameter(\”fileName\”);

System.out.print(\”dddddddddd:\” + name);
// web绝对路径
String path = request.getSession().getServletContext().getRealPath(\”/\”);
String savePath = path + \”upload\”;

// 设置为下载application/x-download
response.setContentType(\”application/x-download\”);
// 即将下载的文件在服务器上的绝对路径
String filenamedownload = savePath + \”/\” + name;
// 下载文件时显示的文件保存名称
String filenamedisplay = name;
// 中文编码转换
filenamedisplay = URLEncoder.encode(filenamedisplay, \”UTF-8\”);
response.addHeader(\”Content-Disposition\”, \”attachment;filename=\”
+ filenamedisplay);
try {
java.io.OutputStream os = response.getOutputStream();
java.io.FileInputStream fis = new java.io.FileInputStream(
filenamedownload);
byte[] b = new byte[1024];
int i = 0;
while ((i = fis.read(b)) > 0) {
os.write(b, 0, i);
}
fis.close();
os.flush();
os.close();
} catch (Exception e) {