java 从ftp下载功能

private static FTPClient getConnect(String chilPath) {
        FTPClient connect = new FTPClient();
        
        try {
            connect.connect(AppConfig.getProperty("fp_host"),
                    Integer.valueOf(AppConfig.getProperty("fp_port")));
            connect.login(AppConfig.getProperty("fp_username"),
                    AppConfig.getProperty("fp_password"));
            connect.setFileType(FTPClient.BINARY_FILE_TYPE);
            if (!FTPReply.isPositiveCompletion(connect.getReplyCode())) {
                connect.disconnect();
            }
            if (StringUtils.isEmpty(chilPath)) {
                connect.changeWorkingDirectory("/");
            } else {
                // 建立新的文件夹，FTP使用ISO8859-1编码方式
                String tempPath = new String((chilPath).getBytes("UTF-8"),
                        "ISO-8859-1");
                connect.makeDirectory(tempPath);
                connect.changeWorkingDirectory(tempPath);
            }
        } catch (Exception e) {
            
        }
        return connect;
}

        /**
         * 下载文件  有子文件夹
         * 
         * @param fileName
         *            文件名
         * @param chilPath
         *            子文件夹路径
         * @return
         */
        public static byte[] downFile(String fileName, String chilPath) {
            FTPClient connect = getConnect(chilPath);
            return downFile(fileName, connect);
        }
     

　　　　　/**
         * 下载文件 无子文件夹
         * 
         * @param fileName
         *            文件名
         * @return
         */
        public static byte[] downFile(String fileName) {
            FTPClient connect = getConnect(null);
            return downFile(fileName, connect);

        }

public static byte[] downFile(String fileName, FTPClient connect) {
        InputStream in = null;
        try {
            FTPFile[] fs = connect.listFiles(fileName);
            // 遍历所有文件，找到指定的文件
            for (FTPFile file : fs) {
                if (file.getName().equals(fileName)) {
                    connect.setBufferSize(1024);
                    connect.setControlEncoding("UTF-8");
                    in = connect.retrieveFileStream(fileName);
                    byte[] b = input2byte(in);
                    return b;
                }
            }
        } catch (Exception e) {
            
        } finally {
            try {
                if (in != null) {
                    in.close();
                }
                connect.logout();
                
            } catch (IOException e) {
            }
        }
        return null;
　　　　}

public static final byte[] input2byte(InputStream inStream)  
        throws IOException {  
    ByteArrayOutputStream swapStream = new ByteArrayOutputStream();  
    byte[] buff = new byte[100];  
    int rc = 0;  
    while ((rc = inStream.read(buff, 0, 100)) > 0) {  
        swapStream.write(buff, 0, rc);  
    }  
    byte[] in2b = swapStream.toByteArray();  
    return in2b;  
} 

/**
 * 获取指定目录文件名
 * 
 * @param path
 * @return
 */
public static String getFileNameByPath(String path) {
    // 先将\\替换成/
    String tempPath = path.replace("\\", "/");
    return path.substring(tempPath.lastIndexOf("/") + 1);

}

public Object downloadFile(String filePath, HttpServletResponse response ) {
    // 子目录地址
    String childPath = getParentPath(filePath, 1);
    // 文件名
    String fileName = getFileNameByPath(filePath);
    // 文件后缀名
    String fileSuffixName = fileName.substring(fileName.lastIndexOf(".") + 1);
    try {
        byte[] outPutStream = null;
        if(childPath == null)
        {
            // 子目录不存在
            outPutStream = downFile(fileName);
        }else
        {
            outPutStream = downFile(fileName, childPath);
        }
        if(outPutStream != null)
        {
            response.reset();
            response.setContentType("application/" + fileSuffixName + ";" + "charset = UTF-8");
            response.setHeader("Content-Disposition", "attachment; filename=" + fileName);
            response.getOutputStream().write(outPutStream);             
            // 以上为一种
//            response.reset();
//            response.setContentType("text/html; charset=utf-8");
//            response.setHeader("Content-Disposition","attachment; filename=" + URLEncoder.encode(完整的文件名+后缀名),"utf-8");
//            response.getOutputStream().write(outPutStream);
            return 200;
        }
        else {
            response.getWriter().write("未找到发票文件，或发票还未开出");
            //return 500;
        }
       
    } catch (Exception e) {
        e.printStackTrace();
        
    }
    return 200;
}

String fp=request.getParameter("fp");
if(StringUtils.isNotEmpty(fp)) {
downloadFile(fp, response);
}