servlet实现文件的上传和下载
jsp表单提交页面
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"
contentType="text/html; charset=UTF-8"
%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>上传的页面</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
</head>
<body>
<form action="${pageContext.request.contextPath }/ServletUploadFile.action" method="post" enctype="multipart/form-data" >
用户名1： <input type="text" name="username" value="usernamevalue" ><br>
用户名2： <input type="text" name="username2" value="username2value"><br>
请选择文件： <input type="file" name="fileUpload" ><br>
<input type="submit" value="上传"><input type="reset" value="重置">
</form>
</body>
</html>
上传文件servlet代码块
package cn.kaka.web.content;
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;
/**
* 文件的上传
*
* @author myluo
*
*/
public class ServletUploadFile extends HttpServlet{
/**
*
*/
private static final long serialVersionUID = 1L;
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
doPost(req, resp);
}
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
try {
//设置request作用域的编码格式
request.setCharacterEncoding("UTF-8");
//设置response作用域的值
response.setContentType("text/html; charset=UTF-8");
//初始化磁盘工厂
DiskFileItemFactory dfif = new DiskFileItemFactory();
//设置临时上传的路径,这里用的是相路径
String itemPath = "/myluo";
//根据这个路径创建一个文件
File f = new File(itemPath);
//判断此文件的在此路径目录是否存在，如果不存在，创建文件夹
if (!f.exists()) {
//创建文件所需的目录
f.mkdirs();
}
//设置上传文件临时目录
dfif.setRepository(f);
//设置缓冲区大小
dfif.setSizeThreshold(4 * 1024 * 1024);//缓存大小为4M
//初始化上传组件
ServletFileUpload sfu = new ServletFileUpload(dfif);
//设置上传文件的大小
sfu.setFileSizeMax(6 * 1024 * 1024);//最大上传为6M
//开始解析上传的文件,达到list集合
List <FileItem> parseRequest = sfu.parseRequest(request);
//获取表单提交的数量
System.out.println("jsp页面表单提交input数量："+parseRequest.size());
//循环遍历list集合
for(FileItem ff:parseRequest){
//System.out.println("获取的是name"+ff.getFieldName()+":value值"+ff.getString());
//判断是否是上传文件
if(ff.getFieldName().equals("fileUpload")){
//获取上传文件名字
String name = ff.getName();
//文件保存的相对路径
String filePath="/myfei/";
//根究相对路径构建决对路径
String realPath = request.getSession().getServletContext().getRealPath(filePath);
System.out.println("写入流的绝对路径："+realPath);
//根究绝对路径创建文件
File fe=new File(realPath);
//判断创建文件的目录是否存在
if(!fe.exists()){
//不存在就构建
fe.mkdirs();
}
//根究文件的名字和路径创建
File obj=new File(realPath,name);
//开始把上传的文件写入
ff.write(obj);
System.out.println("path="+realPath+name);
//把文件保存的路径存到request作用域
request.setAttribute("path", filePath+name);
}else{
//System.out.println("我不是上传文件的值："+ff.getString());
//获取表单提交的值，中文乱码处理
System.out.println(new String(ff.getString().getBytes("ISO-8859-1"),"UTF-8"));
}
}
} catch (Exception e) {
e.printStackTrace();
}
//上传成功以后转发到另一个jsp页面显示
request.getRequestDispatcher("mini.jsp").forward(request, response);
}
}
转发显示的jsp页面mini页面
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"
contentType="text/html; charset=UTF-8"
%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>显示上传文件的界面</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
</head>
<body>
<p>显示上传文件</p>
<p>${path }</p>
<p>${pageContext.request.contextPath }${path }</p>
<img height="500px" whith="500px" src="${pageContext.request.contextPath }${path }" alt="美丽的苹果" >
<p><a href="${pageContext.request.contextPath }/ServletFileDownload.action?path=${path}">下载</a></p>
</body>
</html>servlet文件下载代码块
package cn.kaka.web.content;
import java.io.FileInputStream;
import java.io.IOException;
import java.net.URLEncoder;
import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class ServletFileDownload extends HttpServlet {
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
doPost(req, resp);
}
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
System.out.println("========================xxxxx");
//设置编码格式
request.setCharacterEncoding("UTF-8");
response.setContentType("text/html;chaset=UTF-8");
//获取从链接地址上传来的相对路径
String parameter = request.getParameter("path");
System.out.println("相对路径："+parameter);
//根究相对路径构建绝对路径
String realPath = request.getSession().getServletContext().getRealPath(parameter);
System.out.println("绝对路径："+realPath);
//根究绝对路径获取输入流对象
FileInputStream fim=new FileInputStream(realPath);
//使用输出流往浏览器输出数据
ServletOutputStream sos = response.getOutputStream();
//设置要保存的文件
String filename = parameter.substring(parameter.lastIndexOf("/")+1);
System.out.println("文件名字："+filename);
//设置头文件
response.setHeader("Content-disposition", "attachment;filename="+URLEncoder.encode(filename,"utf-8"));
int len=-1;
byte [] bt=new byte[1024];
while((len=fim.read(bt))!=-1){
sos.write(bt,0,len);
}
fim.close();
sos.close();
}
}
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