Java 上传下载的

1.上传的步骤：

a.导入SmartUpload.jar b.创建一个上传的类的对象 c.初始化 d.上传至服务器 e.保存注意：表单提交时需要指定enctype="multipart/form-data"（多数据类型提交）。

上传的jar包有SmartUpload.jar 和 fastupload-core-0.6.3.jar 可以在网上找一找,它们都可以实现伤上传的功能，我们就用SmartUpload.jar来试一试。

①创建一个Java web 项目（用帕斯卡命名就是首字母小写列如：upioad,ownioad或者upioadOwnioad）

②导包SmartUpload.jar 放在WebRoot→WEB-INF→lib中

③创建一个Servlet的Java类实现HttpServlet接口（用驼峰命名就是每个首字母大写列如：UpioadServlet, OwnioadServlet)

④上传部分的代码（UpioadServlet）

package upioad;

import java.io.IOException;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import com.jspsmart.upload.SmartFile;

import com.jspsmart.upload.SmartFiles;

import com.jspsmart.upload.SmartUpload;

public class UploadServlet<Files> extends HttpServlet {

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

this.doPost(request, response);

}

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

//创建一个上传下载的对象 SmartUpload su=new SmartUpload();

//初始化对象 su.initialize(getServletConfig(), request, response);

try {

//限制上传文件的后缀

su.setAllowedFilesList("txt,doc,jpg");

//设置文件上传的大小限制

su.setMaxFileSize(1024*1024*2);//2M字节数

//上传文件到服务器

su.upload();

SmartFiles fs=su.getFiles();

su.save("/files/");

for(int i=0;i<fs.getCount();i++) {

SmartFile f=fs.getFile(i);

System.out.println(f.getFileExt());

//判断f是否存在

if(f.isMissing()==false)

{

//文件存在.另存为用时间的方式存储文件名重复存储相同的文件,不被覆盖

f.saveAs("/files/"+System.currentTimeMillis()+f.getFileName());

}

//指定文件保存路径

su.save("/files");

System.out.println("上传成功");

request.getRequestDispatcher("../show.jsp").forward(request, response); //内部跳转

} catch (Exception e) {

// TODO Auto-generated catch block

request.setAttribute("eroor","文件格式不正确");

request.getRequestDispatcher("../index.jsp").forward(request, response); //内部跳转

}

jsp 简单页面

<%@ page language="java" import="java.util.*" pageEncoding="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>

</head>

<body>

<input type="submit" value="上传"/>${eroor }

</form>

</body>

</html>

⑤下载部分代码(OwnioadServlet)

package ownioad;

import java.io.IOException;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import com.jspsmart.upload.SmartUpload;

import com.jspsmart.upload.SmartUploadException;

public class DownLoad extends HttpServlet {

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

this.doPost(request, response);

}

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

//获取要下载文件的名称

String name =new String(request.getParameter("name").getBytes("iso-8859-1"),"utf-8");

System.out.println(request.getParameter("name"));

//创建一个上传下载的对象

SmartUpload su=new SmartUpload();

//初始化对象

su.initialize(getServletConfig(), request, response);

try {

//设置下载对象内容不自动打开

su.setContentDisposition(null);

//调用下载的方法

su.downloadFile("/files/"+name);

System.out.println("下载成功！");

} catch (SmartUploadException e) {

// TODO Auto-generated catch block e.printStackTrace();

}

jsp 简单页面

<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>

<%@page import="java.io.File"%> <% 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>

<title>My JSP 'show.jsp' starting page</title>

</head>

<body>

<% File f =new File(application.getRealPath("/files"));

File []fs=f.listFiles();

if(fs!=null && fs.length>0)

{ for(File file:fs)

{ out.print(file.getName());

<%=file.getName() %><br/></a>

}

</body>

</html>

送大家一句话 ;代码虐我千百遍，我视代码如初恋

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Java 上传下载的

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