JAVA - 访问FTP

1、FTP客户端连接与登录

/**
	@ IP:  FTP 服务器IP地址
	@PORT:  FTP 服务器端口
	@USERNAME:  FTP 服务器登录名称
	@PASSWORD: FTP 服务器登录密码
*/
private static FTPClient getFtpClient(String IP, Integer PORT, String USERNAME, String PASSWORD){
    FTPClient ftpClient = null;
    try {
        ftpClient = new FTPClient();
        // 连接FTP服务器
        (IP, PORT);
        //ftp端口的打开和关闭
        ();
        // 登录ftp
        (USERNAME, PASSWORD);
        (FTP.BINARY_FILE_TYPE);  //设置传输文件类型
        int reply = ();
        ("login ftp reply:" + reply);
        if (!(reply)) {
            ();
        }
    }catch (Exception e) {
        StringBuffer sb = new StringBuffer("登陆ftp服务器异常：" + ());
        ("<br>");
        ("FTP地址：" + ());
        ("<br>");
        ("FTP端口号：" + ());
        ("<br>");
        ("FTP用户：" + ());
        ("<br>");
        ("FTP密码：" + ());
        ((), e);
        ftpClient = null;
    }
    return ftpClient;
}

2、下载文件

/**
	@ IP:  FTP 服务器IP地址
	@PORT:  FTP 服务器端口
	@USERNAME:  FTP 服务器登录名称
	@PASSWORD: FTP 服务器登录密码
	@PATH: 要上传至FTP的目标目录
	@Local_Path: 要上传的文件所在路径
	@filename: 要上传的文件名称
*/
public static String receive(String IP,Integer PORT,String USERNAME,String PASSWORD,String PATH, String Local_Path,String filename) {
    boolean result = false;  //接收结果
    FileOutputStream out = null;
    FTPClient ftpClient = null;
    try {
        //获得ftp客户端对象
        ftpClient = getFtpClient(IP, PORT, USERNAME, PASSWORD);
        if(ftpClient == null){
            throw new RuntimeException("ftp init fail!");
        }
        //变更ftp目录
        boolean b = (PATH);
        if(b){
            //获得本地的输出流
            File localPath = new File(Local_Path);
            if (!()) {
                ();
            }
            out = new FileOutputStream(localPath +  + filename);
            result = (filename, out);  //接收到本地
        }else{
            //找不到目录
            throw new RuntimeException("找不到ftp目录：" + PATH);
        }
        return filename;
    } catch (Exception e) {
        throw new RuntimeException("接受文件异常,path=" + PATH + ",filename=" + filename, e);
    }
    finally{
        if(out != null){
            try {
                ();
            } catch (IOException e) {
                ("关闭本地目录异常,path=" + Local_Path, e);
            }
        }
        closeFtpClient(ftpClient);
    }
}

3、发送文件

/**
	@ IP:  FTP 服务器IP地址
	@PORT:  FTP 服务器端口
	@USERNAME:  FTP 服务器登录名称
	@PASSWORD: FTP 服务器登录密码
	@PATH: 要上传至FTP的目标目录
	@Local_Path: 要上传的文件所在路径
	@filename: 要上传的文件名称
*/
public static boolean send(String IP,Integer PORT,String USERNAME,String PASSWORD,String PATH,String Local_Path,String filename){
    boolean result = false;  //发送结果
    FileInputStream in = null;
    FTPClient ftpClient = null;
    try {
        //获得ftp客户端对象
        ftpClient = getFtpClient(IP, PORT, USERNAME, PASSWORD);
        if(ftpClient == null){
            throw new RuntimeException("ftp init fail!");
        }
        (PATH);
        //变更ftp目录
        boolean b = (PATH);
        if(b){
            //获得本地的流
            in = new FileInputStream(Local_Path +  + filename);
            result = (new String((),"ISO-8859-1"), in);
        }else{
            //找不到目录
            throw new RuntimeException("找不到ftp目录：" + PATH);
        }
        return result;
    } catch (Exception e) {
        throw new RuntimeException("发送文件异常,path=" + PATH + ",filename=" + filename, e);
    }
    finally{
        closeFtpClient(ftpClient);
        if(in != null){
            try {
                ();
            } catch (IOException e) {
                ("关闭本地目录异常,path=" + Local_Path, e);
            }
        }
    }
}

4、FTP客户端关闭

private static void closeFtpClient(FTPClient ftpClient){
    try {
        if (ftpClient != null) {
            ();
        }
    } catch (Exception e) {
        ("关闭fTP客户端异常", e);
    }
}