java上传下载ftp服务器的代码！！

import java.io.*;
import java.util.*;
import java.sql.*;
import java.net.Socket;
import java.net.ServerSocket;
import java.net.InetAddress;
import sun.net.ftp.*;
import sun.net.TelnetInputStream;
import sun.net.TelnetOutputStream;

/*
* 用于连接到FTP服务器上
* @return String 若失败则返回失败信息，成功返回空字符串
*/
private String connectToFtpServer(){
if ((this.ftpserver==null)||(this.ftpserver.equals(""))) return "FTP服务器名设置不正确!";

try{
fc.openServer(this.ftpserver);
fc.login(this.ftpuser,this.ftppwd);
fc.ascii();
}catch(FtpLoginException e){
return "没有与FTP服务器连接的权限,或用户名密码设置不正确!";
}catch(IOException e){
return "与FTP服务器连接失败!";
}catch(SecurityException e){
return "没有权限与FTP服务器连接";
}
return "";
}
/*
* 用于关闭与FTP服务器的连接
*/
private void closeFtpConnect(){
if (fc.serverIsOpen()){
try{
fc.closeServer();
}catch(Exception e){
}finally{
fc = null;
}
}
}
public String downloadFile(String fileName){
//只下载文本文件或XML文件
if (!this.isTextFile(fileName)) return fileName + "不是XML文件或文本文件";
String retMessage = "";

if (!fc.serverIsOpen()){
retMessage = this.connectToFtpServer();
if (!retMessage.equals("")) return "下载文件：" + fileName + "时无法和FTP服务器连接";
}

//if (conn == null) return "下载文件：" + fileName + "时无法连接到数据库";

String chkSql = "select 1 from t_trans_log where file_name = '" + fileName + "'";
if (sqlbean.checkQueryRowCount(chkSql) > 0) return retMessage;

if (this.dldir==null) this.dldir = "";

try{


TelnetInputStream is = fc.get(this.dldir + "/" + fileName);
BufferedReader br = new BufferedReader(new InputStreamReader(is));

//读取文件内容到stringbuffer
StringBuffer sb = new StringBuffer();
int length;

char buffer[] = new char[1];
while((length = br.read(buffer,0,1)) != -1) sb.append(buffer);

//构造sql语句插入记录
//String ls_lsh = get_lsh(12);
String ls_lsh = ah.getAutoID("xf_lsh",12);

String ls_sql = "insert into t_trans_log(tran_id,tran_flag,file_name,file_content)values('"
ls_sql += ls_lsh + "','0','" + fileName + "','" + sb.toString() + "')";

conn = connmanager.getConnection();
conn.setAutoCommit(false);

sqlbean.executeUpdate(conn,ls_sql);


//将stringbuffer写入文件中
byte buf[] = sb.toString().getBytes();

OutputStream f1 = new FileOutputStream(this.bdldir + "/" + fileName);
f1.write(buf);
f1.close();

is.close();
br.close();

//删除文件
this.deleteFile(this.dldir + "/" + fileName);

conn.commit();
conn.setAutoCommit(true);
connmanager.close(conn);
}catch(SQLException e){
retMessage = "下载文件：" + fileName + "时发生数据库错误：" + e.getMessage();
}catch(IOException e){
retMessage = "下载文件：" + fileName + "时发生文件读写错误：" + e.getMessage();
}
return retMessage;
}


//下载指定目录下的所有文件
public String downloadFiles(String dirName){
String retMessage = "";

if ((dirName == null)||(dirName.equals(""))) dirName = this.dldir;
String[] sa = this.list();
for (int i = 0;i < sa.length;i++){
retMessage = this.downloadFile(sa[i]);
if (!retMessage.equals("")) return retMessage;
}

return retMessage;
}

//下载FTP服务器上的所有文件
public String downloadFiles(){
return downloadFiles(this.dldir);
}



public String uploadFile(String fileName){
String retMessage = "";

if (!fc.serverIsOpen()){
retMessage = this.connectToFtpServer();
if (!retMessage.equals("")) return "上传文件：" + fileName + "时无法和FTP服务器连接";
}
//if (conn == null) return "上传文件：" + fileName + "时无法连接到数据库";

//String chkSql = "select 1 from t_trans_log where file_name = '" + fileName + "'";
//if (Utils.checkQueryRowCount(conn,chkSql) > 0) return retMessage;

try{
if (this.uldir==null) this.uldir = "";
if (this.buldir==null) this.buldir = "";

TelnetOutputStream os = fc.put(this.uldir + "/" + fileName);
BufferedWriter wr = new BufferedWriter(new OutputStreamWriter(os));

StringBuffer sb = new StringBuffer();
InputStream f1 = new FileInputStream(this.buldir + "/" + fileName);
int size = f1.available();
byte b[] = new byte[size];
while(f1.read(b)!= -1) sb.append(new String(b,0,b.length));

//构造sql语句插入记录
//String ls_sql = "insert into t_trans_log(tran_id,file_name,file_content)values('" + get_lsh(12) + "','" + fileName + "','" + sb.toString() + "')";
String ls_sql = "insert into t_trans_log(tran_id,file_name,file_content)values('" + ah.getAutoID("xf_lsh",12) + "','" + fileName + "','" + sb.toString() + "')";
conn = connmanager.getConnection();
conn.setAutoCommit(false);

sqlbean.executeUpdate(conn,ls_sql);

//写入文件
wr.write(sb.toString());

f1.close();
wr.close();
os.close();

//删除本地文件

File ls_file = new File(this.buldir + "/" + fileName);

ls_file.delete();

conn.commit();
conn.setAutoCommit(true);
connmanager.close(conn);
}catch(SQLException e){
retMessage = "上传文件：" + fileName + "时发生数据库错误：" + e.getMessage();
}catch(IOException e){
retMessage = "上传文件：" + fileName + "时发生文件读写错误：" + e.getMessage();
}

return retMessage;
}

/**
* 功能：获取指定目录文件列表并上传每一个文件
*/
public String uploadFiles(){
String retMessage = "";

if (this.buldir == null) this.buldir = "";

File ls_file = new File(this.buldir);
File[] entries = ls_file.listFiles();

for(int i=0; i<entries></entries> this.uploadFile(entries[i].getName());
if (!retMessage.equals("")) return retMessage;
}
return retMessage;
}

public String deleteFile(String fileName){
String retMessage = "";
try{
Socket socket = new Socket(this.ftpserver,this.ftpport);
BufferedReader reader = new BufferedReader(new InputStreamReader(socket.getInputStream()));
if (!reader.readLine().startsWith("220")) return "DELE 无法连接到指定的FTP服务器";
Writer writer = new OutputStreamWriter(socket.getOutputStream());
writer.write("USER " + this.ftpuser + "rn");
writer.flush();
if (!reader.readLine().startsWith("331")) return "DELE 指定的登录FTP用户名无效";
writer.write("PASS " + this.ftppwd + "rn");
writer.flush();
if (!reader.readLine().startsWith("230")) return "DELE FTP用户的登录口令错误";
writer.write("DELE " + fileName + "rn");
writer.flush();
if (!reader.readLine().startsWith("250")) return "无法删除指定文件" + fileName;
writer.close();
reader.close();
socket.close();
}catch(Exception e){
retMessage = "删除文件" + fileName + "时发生错误" + e.getMessage();
}
return retMessage;
}

/**
* 功能：获取指定目录下以分号分隔的文件名列表
*/
public String getDownloadFileList(String dirName){
StringBuffer sb = new StringBuffer();
String[] sa = list(dirName);
int saLength = sa.length;

for (int i = 0; i < saLength; i++) sb.append(sa[i]).append(";");

return sb.toString();
}

/**
* 功能：获取默认下载目录下以分号分隔的文件名列表
*/
public String getDownloadFileList(){
return getDownloadFileList(this.dldir);
}

/**
* 功能：以数组的形式返回服务器上指定目录下的文件名列表
*/
public String[] list(String dirName){
String[] fileNameList = new String[0];
Vector lines = new Vector();
String line = null;

if (fc.serverIsOpen()){
try{
fc.cd(dirName.equals("")?this.dldir:dirName);
TelnetInputStream ins = fc.list();
fc.cd("/");

LineNumberReader in = new LineNumberReader(new InputStreamReader(ins));
line = in.readLine();
while((line != null)&&!(line.trim().equals(""))&&!(line.trim().equals("/n"))){
lines.add(line.substring(line.lastIndexOf(" ") + 1,line.length()));
line = in.readLine();
}

in.close();
ins.close();
}catch(Exception e){
}

if (!lines.isEmpty()) fileNameList = (String[])lines.toArray(fileNameList);
}

return fileNameList;
}

/**
* 功能：以数组的形式返回服务器上默认下载目录下的文件名列表
*/
public String[] list(){
return this.list(this.dldir);
}

public String getDlDir(){return this.dldir;}

/**
* 功能：用于判断文件是否是XML或TXT文件
*/
private boolean isTextFile(String fileName){
return (fileName.toLowerCase().endsWith(".xml")||fileName.toLowerCase().endsWith(".txt"));
}
}
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