Java实现FTP服务器功能实例代码

ftp(file transfer protocol 文件传输协议)是internet 上用来传送文件的协议。在internet上通过ftp 服务器可以进行文件的上传(upload)或下载(download)。ftp是实时联机服务，在使用它之前必须是具有该服务的一个用户(用户名和口令)，工作时客户端必须先登录到作为服务器一方的计算机上，用户登录后可以进行文件搜索和文件传送等有关操作，如改变当前工作目录、列文件目录、设置传输参数及传送文件等。使用ftp可以传送所有类型的文件，如文本文件、二进制可执行文件、图象文件、声音文件和数据压缩文件等。

ftp 命令

　　ftp 的主要操作都是基于各种命令基础之上的。常用的命令有：
　　 设置传输模式，它包括ascⅱ(文本) 和binary 二进制模式;
　　 目录操作，改变或显示远程计算机的当前目录(cd、dir/ls 命令);
　　 连接操作，open命令用于建立同远程计算机的连接；close命令用于关闭连接;
　　 发送操作，put命令用于传送文件到远程计算机；mput 命令用于传送多个文件到远程计算机;
　　 获取操作，get命令用于接收一个文件；mget命令用于接收多个文件。

import java.net.socket; 
import org.apache.log4j.logger; 
/** 
 * 角色——服务器a 
 * @author leon 
 * 
 */ 
public class servera{ 
  public static void main(string[] args){ 
    final string f_dir = "c:/test";//根路径 
    final int port = 22;//监听端口号 
    logger.getrootlogger(); 
    logger logger = logger.getlogger("com"); 
    try{ 
      serversocket s = new serversocket(port); 
      logger.info("connecting to server a..."); 
      logger.info("connected successful! local port:"+s.getlocalport()+". default directory:'"+f_dir+"'."); 
      while( true ){ 
        //接受客户端请求 
        socket client = s.accept(); 
        //创建服务线程 
        new clientthread(client, f_dir).start(); 
      } 
    } catch(exception e) { 
      logger.error(e.getmessage()); 
      for(stacktraceelement ste : e.getstacktrace()){ 
        logger.error(ste.tostring()); 
      } 
    } 
  } 
} 
import java.io.bufferedreader;  
import java.io.file; 
import java.io.filenotfoundexception; 
import java.io.ioexception; 
import java.io.inputstream; 
import java.io.inputstreamreader; 
import java.io.outputstream; 
import java.io.printwriter; 
import java.io.randomaccessfile; 
import java.net.connectexception; 
import java.net.inetaddress; 
import java.net.serversocket; 
import java.net.socket; 
import java.net.unknownhostexception; 
import java.nio.charset.charset; 
import java.util.random; 
import org.apache.log4j.logger; 
/** 
 * 客户端子线程类 
 * @author leon 
 * 
 */ 
public class clientthread extends thread { 
  private socket socketclient;//客户端socket 
  private logger logger;//日志对象 
  private string dir;//绝对路径 
  private string pdir = "/";//相对路径 
  private final static random generator = new random();//随机数 
  public clientthread(socket client, string f_dir){ 
    this.socketclient = client; 
    this.dir = f_dir; 
  } 
  @override 
  public void run() { 
    logger.getrootlogger(); 
    logger = logger.getlogger("com"); 
    inputstream is = null; 
    outputstream os = null; 
    try { 
      is = socketclient.getinputstream(); 
      os = socketclient.getoutputstream(); 
    } catch (ioexception e) { 
      logger.error(e.getmessage()); 
      for(stacktraceelement ste : e.getstacktrace()){ 
        logger.error(ste.tostring()); 
      } 
    } 
    bufferedreader br = new bufferedreader(new inputstreamreader(is, 
        charset.forname("utf-8"))); 
    printwriter pw = new printwriter(os); 
    string clientip = socketclient.getinetaddress().tostring().substring(1);//记录客户端ip 
    string username = "not logged in";//用户名 
    string password = "";//口令 
    string command = "";//命令 
    boolean loginstuts = false;//登录状态 
    final string login_warning = "530 please log in with user and pass first."; 
    string str = "";//命令内容字符串 
    int port_high = 0; 
    int port_low = 0; 
    string retr_ip = "";//接收文件的ip地址 
    socket tempsocket = null; 
    //打印欢迎信息 
    pw.println("220-ftp server a version 1.0 written by leon guo"); 
    pw.flush(); 
    logger.info("("+username+") ("+clientip+")> connected, sending welcome message..."); 
    logger.info("("+username+") ("+clientip+")> 220-ftp server a version 1.0 written by leon guo"); 
    boolean b = true; 
    while ( b ){ 
      try { 
        //获取用户输入的命令 
        command = br.readline(); 
        if(null == command) break; 
      } catch (ioexception e) { 
        pw.println("331 failed to get command"); 
        pw.flush(); 
        logger.info("("+username+") ("+clientip+")> 331 failed to get command"); 
        logger.error(e.getmessage()); 
        for(stacktraceelement ste : e.getstacktrace()){ 
          logger.error(ste.tostring()); 
        } 
        b = false; 
      } 
      /* 
       * 访问控制命令 
       */ 
      // user命令 
      if(command.touppercase().startswith("user")){ 
        logger.info("(not logged in) ("+clientip+")> "+command); 
        username = command.substring(4).trim();  
        if("".equals(username)){ 
          pw.println("501 syntax error"); 
          pw.flush(); 
          logger.info("(not logged in) ("+clientip+")> 501 syntax error"); 
          username = "not logged in"; 
        } 
        else{ 
          pw.println("331 password required for " + username); 
          pw.flush(); 
          logger.info("(not logged in) ("+clientip+")> 331 password required for " + username); 
        } 
        loginstuts = false; 
      } //end user 
      // pass命令 
      else if(command.touppercase().startswith("pass")){ 
        logger.info("(not logged in) ("+clientip+")> "+command); 
        password = command.substring(4).trim();  
        if(username.equals("root") && password.equals("root")){ 
          pw.println("230 logged on"); 
          pw.flush(); 
          logger.info("("+username+") ("+clientip+")> 230 logged on"); 
//         logger.info("客户端 "+clientip+" 通过 "+username+"用户登录"); 
          loginstuts = true; 
        } 
        else{ 
          pw.println("530 login or password incorrect!"); 
          pw.flush(); 
          logger.info("(not logged in) ("+clientip+")> 530 login or password incorrect!"); 
          username = "not logged in"; 
        } 
      } //end pass 
      // pwd命令 
      else if(command.touppercase().startswith("pwd")){ 
        logger.info("("+username+") ("+clientip+")> "+command); 
        if(loginstuts){ 
//         logger.info("用户"+clientip+"："+username+"执行pwd命令"); 
          pw.println("257 /""+pdir+"/" is current directory"); 
          pw.flush(); 
          logger.info("("+username+") ("+clientip+")> 257 /""+pdir+"/" is current directory"); 
        } 
        else{ 
          pw.println(login_warning); 
          pw.flush(); 
          logger.info("("+username+") ("+clientip+")> "+login_warning); 
        } 
      } //end pwd 
      // cwd命令 
      else if(command.touppercase().startswith("cwd")){ 
        logger.info("("+username+") ("+clientip+")> "+command); 
        if(loginstuts){ 
          str = command.substring(3).trim(); 
          if("".equals(str)){ 
            pw.println("250 broken client detected, missing argument to cwd. /""+pdir+"/" is current directory."); 
            pw.flush(); 
            logger.info("("+username+") ("+clientip+")> 250 broken client detected, missing argument to cwd. /""+pdir+"/" is current directory."); 
          } 
          else{ 
            //判断目录是否存在 
            string tmpdir = dir + "/" + str; 
            file file = new file(tmpdir); 
            if(file.exists()){//目录存在 
              dir = dir + "/" + str; 
              if("/".equals(pdir)){ 
                pdir = pdir + str; 
              } 
              else{ 
                pdir = pdir + "/" + str; 
              } 
//             logger.info("用户"+clientip+"："+username+"执行cwd命令"); 
              pw.println("250 cwd successful. /""+pdir+"/" is current directory"); 
              pw.flush(); 
              logger.info("("+username+") ("+clientip+")> 250 cwd successful. /""+pdir+"/" is current directory"); 
            } 
            else{//目录不存在 
              pw.println("550 cwd failed. /""+pdir+"/": directory not found."); 
              pw.flush(); 
              logger.info("("+username+") ("+clientip+")> 550 cwd failed. /""+pdir+"/": directory not found."); 
            } 
          } 
        } 
        else{ 
          pw.println(login_warning); 
          pw.flush(); 
          logger.info("("+username+") ("+clientip+")> "+login_warning); 
        } 
      } //end cwd 
      // quit命令 
      else if(command.touppercase().startswith("quit")){ 
        logger.info("("+username+") ("+clientip+")> "+command); 
        b = false; 
        pw.println("221 goodbye"); 
        pw.flush(); 
        logger.info("("+username+") ("+clientip+")> 221 goodbye"); 
        try { 
          thread.currentthread(); 
          thread.sleep(1000); 
        } catch (interruptedexception e) { 
          logger.error(e.getmessage()); 
          for(stacktraceelement ste : e.getstacktrace()){ 
            logger.error(ste.tostring()); 
          } 
        } 
      } //end quit 
      /* 
       * 传输参数命令 
       */ 
      //port命令，主动模式传输数据 
      else if(command.touppercase().startswith("port")){ 
        logger.info("("+username+") ("+clientip+")> "+command); 
        if(loginstuts){ 
          try { 
            str = command.substring(4).trim(); 
            port_low = integer.parseint(str.substring(str.lastindexof(",")+1)); 
            port_high = integer.parseint(str.substring(0, str.lastindexof(",")) 
                .substring(str.substring(0, str.lastindexof(",")).lastindexof(",")+1)); 
            string str1 = str.substring(0, str.substring(0, str.lastindexof(",")).lastindexof(",")); 
            retr_ip = str1.replace(",", "."); 
            try { 
              //实例化主动模式下的socket 
              tempsocket = new socket(retr_ip,port_high * 256 + port_low); 
//             logger.info("用户"+clientip+"："+username+"执行port命令"); 
              pw.println("200 port command successful"); 
              pw.flush(); 
              logger.info("("+username+") ("+clientip+")> 200 port command successful"); 
            } catch (connectexception ce) { 
              pw.println("425 can't open data connection."); 
              pw.flush(); 
              logger.info("("+username+") ("+clientip+")> 425 can't open data connection."); 
              logger.error(ce.getmessage()); 
              for(stacktraceelement ste : ce.getstacktrace()){ 
                logger.error(ste.tostring()); 
              } 
            } catch (unknownhostexception e) { 
              logger.error(e.getmessage()); 
              for(stacktraceelement ste : e.getstacktrace()){ 
                logger.error(ste.tostring()); 
              } 
            } catch (ioexception e) { 
              logger.error(e.getmessage()); 
              for(stacktraceelement ste : e.getstacktrace()){ 
                logger.error(ste.tostring()); 
              } 
            } 
          } catch (numberformatexception e) { 
            pw.println("503 bad sequence of commands."); 
            pw.flush(); 
            logger.info("("+username+") ("+clientip+")> 503 bad sequence of commands."); 
            logger.error(e.getmessage()); 
            for(stacktraceelement ste : e.getstacktrace()){ 
              logger.error(ste.tostring()); 
            } 
          } 
        } 
        else{ 
          pw.println(login_warning); 
          pw.flush(); 
          logger.info("("+username+") ("+clientip+")> "+login_warning); 
        } 
      } //end port 
      //pasv命令，被动模式传输数据 
      else if(command.touppercase().startswith("pasv")) {  
        logger.info("("+username+") ("+clientip+")> "+command); 
        if(loginstuts){ 
          serversocket ss = null; 
          while( true ){ 
            //获取服务器空闲端口 
            port_high = 1 + generator.nextint(20); 
            port_low = 100 + generator.nextint(1000); 
            try { 
              //服务器绑定端口 
              ss = new serversocket(port_high * 256 + port_low); 
              break; 
            } catch (ioexception e) { 
              continue; 
            } 
          } 
//         logger.info("用户"+clientip+"："+username+"执行pasv命令"); 
          inetaddress i = null; 
          try { 
            i = inetaddress.getlocalhost(); 
          } catch (unknownhostexception e1) { 
            e1.printstacktrace(); 
          } 
          pw.println("227 entering passive mode ("+i.gethostaddress().replace(".", ",")+","+port_high+","+port_low+")"); 
          pw.flush(); 
          logger.info("("+username+") ("+clientip+")> 227 entering passive mode ("+i.gethostaddress().replace(".", ",")+","+port_high+","+port_low+")"); 
          try { 
            //被动模式下的socket 
            tempsocket = ss.accept(); 
            ss.close(); 
          } catch (ioexception e) { 
            logger.error(e.getmessage()); 
            for(stacktraceelement ste : e.getstacktrace()){ 
              logger.error(ste.tostring()); 
            } 
          } 
        } 
        else{ 
          pw.println(login_warning); 
          pw.flush(); 
          logger.info("("+username+") ("+clientip+")> "+login_warning); 
        } 
      } //end pasv 
      //retr命令 
      else if(command.touppercase().startswith("retr")){ 
        logger.info("("+username+") ("+clientip+")> "+command); 
        if(loginstuts){ 
          str = command.substring(4).trim(); 
          if("".equals(str)){ 
            pw.println("501 syntax error"); 
            pw.flush(); 
            logger.info("("+username+") ("+clientip+")> 501 syntax error"); 
          } 
          else { 
            try { 
              pw.println("150 opening data channel for file transfer."); 
              pw.flush(); 
              logger.info("("+username+") ("+clientip+")> 150 opening data channel for file transfer."); 
              randomaccessfile outfile = null; 
              outputstream outsocket = null; 
              try { 
                //创建从中读取和向其中写入（可选）的随机访问文件流，该文件具有指定名称 
                outfile = new randomaccessfile(dir+"/"+str,"r"); 
                outsocket = tempsocket.getoutputstream();  
              } catch (filenotfoundexception e) {  
                logger.error(e.getmessage()); 
                for(stacktraceelement ste : e.getstacktrace()){ 
                  logger.error(ste.tostring()); 
                } 
              } catch (ioexception e) { 
                logger.error(e.getmessage()); 
                for(stacktraceelement ste : e.getstacktrace()){ 
                  logger.error(ste.tostring()); 
                } 
              }  
              byte bytebuffer[]= new byte[1024];  
              int length;  
              try{  
                while((length = outfile.read(bytebuffer)) != -1){  
                  outsocket.write(bytebuffer, 0, length);  
                }  
                outsocket.close();  
                outfile.close();  
                tempsocket.close();  
              }  
              catch(ioexception e){ 
                logger.error(e.getmessage()); 
                for(stacktraceelement ste : e.getstacktrace()){ 
                  logger.error(ste.tostring()); 
                } 
              } 
//             logger.info("用户"+clientip+"："+username+"执行retr命令"); 
              pw.println("226 transfer ok"); 
              pw.flush(); 
              logger.info("("+username+") ("+clientip+")> 226 transfer ok"); 
            } catch (exception e){ 
              pw.println("503 bad sequence of commands."); 
              pw.flush(); 
              logger.info("("+username+") ("+clientip+")> 503 bad sequence of commands."); 
              logger.error(e.getmessage()); 
              for(stacktraceelement ste : e.getstacktrace()){ 
                logger.error(ste.tostring()); 
              } 
            } 
          } 
        } 
        else{ 
          pw.println(login_warning); 
          pw.flush(); 
          logger.info("("+username+") ("+clientip+")> "+login_warning); 
        } 
      }//end retr 
      //stor命令 
      else if(command.touppercase().startswith("stor")){  
        logger.info("("+username+") ("+clientip+")> "+command); 
        if(loginstuts){ 
          str = command.substring(4).trim(); 
          if("".equals(str)){ 
            pw.println("501 syntax error"); 
            pw.flush(); 
            logger.info("("+username+") ("+clientip+")> 501 syntax error"); 
          } 
          else { 
            try { 
              pw.println("150 opening data channel for file transfer.");  
              pw.flush(); 
              logger.info("("+username+") ("+clientip+")> 150 opening data channel for file transfer."); 
              randomaccessfile infile = null; 
              inputstream insocket = null; 
              try { 
                infile = new randomaccessfile(dir+"/"+str,"rw"); 
                insocket = tempsocket.getinputstream();  
              } catch (filenotfoundexception e) {  
                logger.error(e.getmessage());  
                for(stacktraceelement ste : e.getstacktrace()){ 
                  logger.error(ste.tostring()); 
                } 
              } catch (ioexception e) { 
                logger.error(e.getmessage());  
                for(stacktraceelement ste : e.getstacktrace()){ 
                  logger.error(ste.tostring()); 
                } 
              }  
              byte bytebuffer[] = new byte[1024];  
              int length;  
              try{ 
                while((length =insocket.read(bytebuffer) )!= -1){  
                  infile.write(bytebuffer, 0, length);  
                } 
                insocket.close();  
                infile.close();  
                tempsocket.close();  
              }  
              catch(ioexception e){ 
                logger.error(e.getmessage()); 
                for(stacktraceelement ste : e.getstacktrace()){ 
                  logger.error(ste.tostring()); 
                } 
              } 
//             logger.info("用户"+clientip+"："+username+"执行stor命令"); 
              pw.println("226 transfer ok"); 
              pw.flush(); 
              logger.info("("+username+") ("+clientip+")> 226 transfer ok"); 
            } catch (exception e){ 
              pw.println("503 bad sequence of commands."); 
              pw.flush(); 
              logger.info("("+username+") ("+clientip+")> 503 bad sequence of commands."); 
              logger.error(e.getmessage()); 
              for(stacktraceelement ste : e.getstacktrace()){ 
                logger.error(ste.tostring()); 
              } 
            } 
          } 
        } else { 
          pw.println(login_warning); 
          pw.flush(); 
          logger.info("("+username+") ("+clientip+")> "+login_warning); 
        } 
      } //end stor 
      //nlst命令 
      else if(command.touppercase().startswith("nlst")) {  
        logger.info("("+username+") ("+clientip+")> "+command); 
        if(loginstuts){ 
          try { 
            pw.println("150 opening data channel for directory list.");  
            pw.flush(); 
            logger.info("("+username+") ("+clientip+")> 150 opening data channel for directory list."); 
            printwriter pwr = null; 
            try { 
              pwr= new printwriter(tempsocket.getoutputstream(),true); 
            } catch (ioexception e1) { 
              e1.printstacktrace(); 
            }  
            file file = new file(dir);  
            string[] dirstructure = new string[10];  
            dirstructure= file.list();  
            for(int i=0;i<dirstructure.length;i++){ 
              pwr.println(dirstructure[i]);  
            } 
            try { 
              tempsocket.close(); 
              pwr.close(); 
            } catch (ioexception e) { 
              logger.error(e.getmessage()); 
              for(stacktraceelement ste : e.getstacktrace()){ 
                logger.error(ste.tostring()); 
              } 
            }  
//           logger.info("用户"+clientip+"："+username+"执行nlst命令"); 
            pw.println("226 transfer ok");  
            pw.flush(); 
            logger.info("("+username+") ("+clientip+")> 226 transfer ok"); 
          } catch (exception e){ 
            pw.println("503 bad sequence of commands."); 
            pw.flush(); 
            logger.info("("+username+") ("+clientip+")> 503 bad sequence of commands."); 
            logger.error(e.getmessage()); 
            for(stacktraceelement ste : e.getstacktrace()){ 
              logger.error(ste.tostring()); 
            } 
          } 
        }else{ 
          pw.println(login_warning); 
          pw.flush(); 
          logger.info("("+username+") ("+clientip+")> "+login_warning); 
        } 
      } //end nlst 
      //list命令 
      else if(command.touppercase().startswith("list")) {  
        logger.info("("+username+") ("+clientip+")> "+command); 
        if(loginstuts){ 
          try{ 
            pw.println("150 opening data channel for directory list.");  
            pw.flush(); 
            logger.info("("+username+") ("+clientip+")> 150 opening data channel for directory list."); 
            printwriter pwr = null; 
            try { 
              pwr= new printwriter(tempsocket.getoutputstream(),true); 
            } catch (ioexception e) { 
              logger.error(e.getmessage()); 
              for(stacktraceelement ste : e.getstacktrace()){ 
                logger.error(ste.tostring()); 
              } 
            }  
            ftputil.getdetaillist(pwr, dir); 
            try { 
              tempsocket.close(); 
              pwr.close(); 
            } catch (ioexception e) { 
              logger.error(e.getmessage()); 
              for(stacktraceelement ste : e.getstacktrace()){ 
                logger.error(ste.tostring()); 
              } 
            }  
//           logger.info("用户"+clientip+"："+username+"执行list命令"); 
            pw.println("226 transfer ok");  
            pw.flush(); 
            logger.info("("+username+") ("+clientip+")> 226 transfer ok"); 
          } catch (exception e){ 
            pw.println("503 bad sequence of commands."); 
            pw.flush(); 
            logger.info("("+username+") ("+clientip+")> 503 bad sequence of commands."); 
            logger.error(e.getmessage()); 
            for(stacktraceelement ste : e.getstacktrace()){ 
              logger.error(ste.tostring()); 
            } 
          } 
        } else { 
          pw.println(login_warning); 
          pw.flush(); 
          logger.info("("+username+") ("+clientip+")> "+login_warning); 
        } 
      } //end list 
      // 输入非法命令 
      else{ 
        logger.info("("+username+") ("+clientip+")> "+command); 
        pw.println("500 syntax error, command unrecognized."); 
        pw.flush(); 
        logger.info("("+username+") ("+clientip+")> 500 syntax error, command unrecognized."); 
      } 
    } //end while 
    try { 
      logger.info("("+username+") ("+clientip+")> disconnected."); 
//     logger.info("用户"+clientip+"："+username+"退出"); 
      br.close(); 
      socketclient.close(); 
      pw.close(); 
      if(null != tempsocket){ 
        tempsocket.close(); 
      } 
    } catch (ioexception e) { 
      logger.error(e.getmessage()); 
      for(stacktraceelement ste : e.getstacktrace()){ 
        logger.error(ste.tostring()); 
      } 
    } 
  } 
} 
import java.io.file;  
import java.io.printwriter; 
import java.text.simpledateformat; 
import java.util.date; 
/** 
 * ftp工具类 
 * @author leon 
 * 
 */ 
public class ftputil { 
  public static void getdetaillist(printwriter pw, string path){ 
    file dir = new file(path); 
    if (!dir.isdirectory()) { 
      pw.println("500 no such file or directory./r/n"); 
    } 
    file[] files = dir.listfiles(); 
    string modifydate; 
    for (int i = 0; i < files.length; i++) { 
      modifydate = new simpledateformat("yyyy/mm/dd hh:mm:ss") 
          .format(new date(files[i].lastmodified())); 
      if (files[i].isdirectory()) { 
        pw.println("drwxr-xr-x ftp   ftp      0 " 
            + modifydate + " " + files[i].getname()); 
      } else { 
        pw.println("-rw-r-r--1 ftp   ftp      " 
            + files[i].length() + " " + modifydate + " " 
            + files[i].getname()); 
      } 
      pw.flush(); 
    } 
    pw.println("total:" + files.length); 
  } 
} 
### set log levels ### 
log4j.logger.com =debug,stdout,d,e 
### 输出到控制台 ### 
log4j.appender.stdout=org.apache.log4j.consoleappender 
log4j.appender.stdout.target=system.out 
log4j.appender.stdout.layout=org.apache.log4j.patternlayout 
log4j.appender.stdout.layout.conversionpattern = %d{absolute} %5p %c{1}:%l - %m%n 
## 输出debug级别以上的日志 
log4j.appender.d=org.apache.log4j.dailyrollingfileappender 
log4j.appender.d.file=c:/logs/logs.log 
log4j.appender.d.append =true 
## 输出debug级别以上的日志 
log4j.appender.d.threshold=debug 
log4j.appender.d.layout=org.apache.log4j.patternlayout 
log4j.appender.d.layout.conversionpattern = %-d{yyyy-mm-dd hh:mm:ss} [ %t:%r ] - [ %p ] %m%n 
### 保存异常信息到单独文件 ### 
log4j.appender.e=org.apache.log4j.dailyrollingfileappender 
## 异常日志文件名 
log4j.appender.e.file=c:/logs/errors.log 
log4j.appender.e.append=true 
## 只输出error级别以上的日志!!! 
log4j.appender.e.threshold=error 
log4j.appender.e.layout=org.apache.log4j.patternlayout 
log4j.appender.e.layout.conversionpattern = %-d{yyyy-mm-dd hh:mm:ss} [ %t:%r ] - [ %p ] %m%n 

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