在一般的web应用中，文件上传可以分为两类（ftp上传和http上传）。其中http上传是在页面的form表单中加入<input type=“file“ name=“file“>类型的接口，当表单被提交时，file中所指的文件就会被写入request对象中。那么在服务器端，用户只要根据rfc1867协议解析request中的数据流就可以得到文件，但是这样上传的速度很慢了，并且对文件的大小又要求。相比之下，ftp上传就很优越了。他是ftp客户端直接与ftp服务器进行交互，将文件创传到ftp服务器。当然，ftp客户端已经被实现。下面我们就应用第三方ftp客户端实现ftp上传。
首先，从www.enterprisedt.com下载ftp客户端。整个应用公有五个类组成Upload.java,FileUpload.java,DirectoryUpload.java,Directory.java,UploadException.java.希望大家改进。
/*
* @(#)Upload.java 1.0 04/11/17
* 实现上传前的初始化
*/
package com.head.upload;
//调用第三方ftp客户端，可在www.enterprisedt.com下载
import com.enterprisedt.net.ftp.*;
import java.io.*;
public class Upload {
static FTPClient ftpClient;
static String path;
//ftp服务器的ip地址，登陆用户和密码
String remoteAddress="127.0.0.1",userName="xie",password="xie";
Upload(){}
Upload(String path){
this.path = path;
}
public boolean config(String fileName) throws UploadException {
//从配置文件中读取远端地址，用户名和密码（没实现）
return false;
}
public void init() throws UploadException {
try{
ftpClient = new FTPClient(this.remoteAddress);
ftpClient.login(this.userName,this.password);
ftpClient.setConnectMode(FTPConnectMode.PASV);
ftpClient.setType(FTPTransferType.BINARY);
}catch(Exception e)
{
throw new UploadException(e.toString(),"Upload.init()");
}
}
public boolean upload() throws UploadException {
File file = null;
boolean flag = false;
try{
init();
file = new File(path);
if(file.isFile() && new FileUpload().uploadFile())
flag = true;
else if(file.isDirectory() && new DirectoryUpload().uploadFile(path))
flag = true;
}catch(Exception e)
{
throw new UploadException(e.toString(),"Upload.upload()");
}
finally{
clear(ftpClient);
}
return flag;
}
boolean clear(FTPClient ftpClient) throws UploadException {
try{
ftpClient.quit();
return true;
}catch(Exception e)
{
throw new UploadException(e.toString(),"Upload.clear(ftpClient)");
}
}
}
}
/*
* @(#)FileUpload.java 1.0 04/11/17
*
* 上传单个文件
*/
package com.head.upload;
import com.enterprisedt.net.ftp.*;
import java.io.*;
public class FileUpload extends Upload {
FileUpload(){}
public boolean uploadFile() throws UploadException{
//the name of file will be changed to avoid iteration
String fileName = path.substring(path.lastIndexOf("\\")+1);
try{
ftpClient.put(path,fileName);
return true;
}catch(Exception e){
throw new UploadException(e.toString(),"FileUpload.uploadFile()");
}
}
public boolean uploadFile(String name) throws UploadException{
//the name of file will be changed to avoid iteration
String fileName = name.substring(name.lastIndexOf("\\")+1);
try{
ftpClient.put(name,fileName);
return true;
}catch(Exception e){
throw new UploadException(e.toString(),"FileUpload.uploadFile(name)");
}
}
}
*
* @(#)DirectoryUpload.java 1.0 04/11/17
*
* 上传文件夹
*/
package com.head.upload;
import com.enterprisedt.net.ftp.*;
import java.io.*;
public class DirectoryUpload extends Upload {
DirectoryUpload(){}
public boolean uploadFile(String dir) throws UploadException{
//the name of directory will be changed to avoid iteration
String dirName = dir.substring(dir.lastIndexOf("\\")+1);
ftpMkDir(dirName);
try{
String currentDir = ftpClient.pwd();
ftpClient.chdir(dirName);
String[] subFiles = new Directory(dir).fileNames();
for(int i=0;i<subFiles.length;i++) {
String tmpP = dir +"\\" + subFiles[i];
if(new File(tmpP).isFile()) {
System.out.println("upload file:"+tmpP);
new FileUpload().uploadFile(tmpP);
}
else{
System.out.println("into the directory:"+tmpP);
uploadFile(tmpP);
}
}
ftpClient.chdir(currentDir);
}catch(Exception e){
throw new UploadException(e.toString(),"DirecotryUpload.uploadFile()");
}
return false;
}
private synchronized void ftpMkDir(String dirName) throws UploadException{
try{
ftpClient.mkdir(dirName);
}catch(Exception e)
{
throw new UploadException(e.toString(),"DirecotryUpload.ftpMkDir(dirName)");
}
}
}
/*
* @(#)Directory.java 1.0 04/11/17
*
*
*/
package com.head.upload;
import com.enterprisedt.net.ftp.*;
import java.io.*;
public class Directory {
private String path;
Directory(){}
Directory(String path) {
this.path = path;
}
//返回一个目录下所有的文件
String[] fileNames() {
String[] subNames = null;
try{
File file = new File(path);
subNames = file.list();
}catch(Exception e)
{
System.out.println(e.toString());
}
return subNames;
}
}
/*
* @(#)UploadException.java 1.0 04/11/17
*
*
*/
package com.head.upload;
public class UploadException extends Exception {
UploadException(String eInfo,String location) {
String info = "The error("+eInfo+") occur in "+location;
System.out.println(info);
}
}