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);     } 
} 
 好了,就这么多了。其中要更改的地方已经注明,希望大家有时间实现 
   
 
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