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>
<base href="<%=basePath%>">
<title>上传页面</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="servlet/UploadServlet" method="post" enctype="multipart/form-data">
<input type="file" name="myfile" ><br><br>
<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>
<base href="<%=basePath%>">
<title>My JSP 'show.jsp' starting page</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>
<% 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());
%>
<a href="fig?name=<%=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
