文件上传在web应用中是非常常见的,现在我就介绍下基于servlet的文件上传,基于Struts2的文件上传可以看:
页面端代码:
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<%@ page language="java" import="java.util.*" pageEncoding="GBK"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
< html >
< head >
< title >注册</ title >
</ head >
< body >
< form name = "form1" onsubmit = "return on_submit()"
action = "RegisterServlet" method = "post" enctype = "multipart/form-data" >
< input type = "text" name = "uname1" id = "password" />
< input type = "text" name = "uname2" id = "uname2" />
< input type = "password" name = "password1" id = "password" />
< input type = "password" name = "password2" id = "password" />
< input type = "radio" value = "男" checked = "checked" name = "sex" />男
< input type = "radio" value = "女" name = "sex" />女
< input type = "text" name = "email" value = "" class = "box" id = "login" />
< br />< br />
< input type = "file" name = "file1" id = "file" />
< input type = "submit" name = "submit" value = "完成注册" />
</ form >
</ body >
</ html >
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这里要注意的一点就是存在文件上传的form表单必须封装为enctype="multipart/form-data";这里我们直接与后台进行交互,不进行Ajax交互,需要使用ajax可以看:http://www.cnblogs.com/shenliang123/category/372520.html
下面我们继续来看servlet的代码实现:
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package com.xidian.bbs.servlet;
import java.io.IOException;
import java.io.PrintWriter;
import java.net.InetAddress;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.Statement;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.jsp.JspFactory;
import javax.servlet.jsp.PageContext;
import com.jspsmart.upload.*;
import com.xidian.bbs.bean.Bean;
import com.xidian.bbs.bean.RegisterBean;
import com.xidian.bbs.util.DBAccess;
import com.xidian.bbs.util.IpTimeStamp;
@SuppressWarnings ( "serial" )
public class RegisterServlet extends HttpServlet{
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType( "text/html" );
response.setCharacterEncoding( "GBK" );
request.setCharacterEncoding( "GBK" );
SmartUpload smart= new SmartUpload();
try {
//PageContext是jsp的内置对象,在servlet不能直接使用,需要做一些处理
JspFactory _jspxFactory = null ;
PageContext pageContext = null ;
_jspxFactory = JspFactory.getDefaultFactory();
pageContext = _jspxFactory.getPageContext( this ,request,response, "" , true , 8192 , true );
smart.initialize(pageContext); //初始化上传操作
smart.upload();
IpTimeStamp its= new IpTimeStamp(InetAddress.getLocalHost().getHostAddress()); //request.getRemoteAddr()获得用户的ip地址
//System.out.println("获取的ip为"+InetAddress.getLocalHost().getHostAddress());
//如果要实现文件的批量上传,则只需用for循环,将getFile(0)中的0改为i即可
String ext=smart.getFiles().getFile( 0 ).getFileExt(); //此为得到文件的扩展名,getFile(0)为得到唯一的一个上传文件
String fileName=its.getIpTimeRand()+ "." +ext;
//System.out.println("获取 的文件名为"+fileName);
//this.getServletContext().getRealPath("/")为得到tomcat的跟目录,放于upload文件夹中,java.io.File.separator是一种安全操作
//String realPath="";
//this.getServletContext().getRealPath("/")+
smart.getFiles().getFile( 0 ).saveAs( "/headupload" +java.io.File.separator+fileName);
String realPath= "headupload/" +fileName+ "" ;
//
//由于前面的form表单已经进行了封装,这里就不能简单的用request.getparameter()来获取表单参数
String uname1 = smart.getRequest().getParameter( "uname1" ); //昵称
String upass1 = smart.getRequest().getParameter( "password1" );
String sex = smart.getRequest().getParameter( "sex" );
String uname2 = smart.getRequest().getParameter( "uname2" ); //用户名
String email = smart.getRequest().getParameter( "email" );
PrintWriter out = response.getWriter();
//以下是持久层操作,省略。。。。。。。。。。
}
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request,response);
}
}
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上面使用到的ip+时间戳的类IpTimeStamp对文件进行重命名:
在上传文件等操作中,我们为了不让文件名冲突,都会进行重命名操作,这里就介绍一个实现IP+时间戳的命名:
直接上代码了,也没什么好说的,实现还是挺简单的,不过实用
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package com.xidian.bbs.util;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Random;
public class IpTimeStamp {
private SimpleDateFormat sim= null ; //用来获取时间
private String ip= null ;
public IpTimeStamp(){
}
public IpTimeStamp(String ip){
this .ip=ip;
}
public String getIpTimeRand(){
StringBuffer sbf= new StringBuffer();
if ( this .ip!= null ){
String a[]= this .ip.split( "\\." ); //根据点来拆分ip地址,但点要转义
for ( int i= 0 ;i<a.length;i++){
sbf.append( this .addZero(a[i], 3 )); //调用补零的方法,每块ip不足三位的自动补足到三位
}
sbf.append( this .getTimeStamp()); //用this来调用外部的方法
Random random= new Random(); //要产生随机数
for ( int i= 0 ;i< 3 ;i++){ //产生三位随机数
sbf.append(random.nextInt( 10 )); //每位随机数都不超过10
}
}
return sbf.toString();
}
@SuppressWarnings ( "unused" )
private String getDate(){ //关于日期与时间的实现
this .sim= new SimpleDateFormat( "yyyy-mm-dd hh:mm:ss.SSS" );
return this .sim.format( new Date());
}
private String getTimeStamp(){ //返回时间戳
this .sim= new SimpleDateFormat( "yyyymmddhhmmssSSS" );
return this .sim.format( new Date());
}
private String addZero(String str, int len){ //自动补零的方法,参数为指定的字符串和长度
StringBuffer s= new StringBuffer();
s.append(str);
while (s.length()<len){
s.insert( 0 , "0" ); //在零的位置上进行补零操作
}
return s.toString();
}
//做测试
public static void main(String [] ary){
IpTimeStamp IpTimeStamp= new IpTimeStamp( "172.168.3.222" ); //调用有参数的构造方法
System.out.println(IpTimeStamp.getIpTimeRand());
}
}
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以上就是本文的全部内容,希望对大家的学习有所帮助,也希望大家多多支持服务器之家。