java使用ftp下载文件到本地（只是下载）

一时失言乱红尘 2022-06-01 09:06 461阅读 0赞

1.添加依赖  
        camel-ftp依赖与commons-net依赖两者取其中一个即可  
        <dependency>  
            <groupId>org.apache.camel</groupId>  
            <artifactId>camel-ftp</artifactId>  
            <version>2.13.2</version>  
        </dependency>  
        <dependency>  
            <groupId>commons-net</groupId>  
            <artifactId>commons-net</artifactId>  
            <version>3.6</version>  
        </dependency>  
2.辅助类  
package com.zq.util;  
  
import org.apache.commons.logging.Log;  
import org.apache.commons.logging.LogFactory;  
import org.apache.commons.net.ftp.FTPClient;  
import org.apache.commons.net.ftp.FTPReply;  
  
import java.io.\*;  
import java.net.SocketException;  
/\*\*  
 \* Created by java1 on 2018/1/23 0031.  
 \*/  
  
public class FtpUtil \{  
  
    private final static Log logger = LogFactory.getLog(FtpUtil.class);  
  
    /\*\*  
     \* 获取FTPClient对象  
     \*  
     \* @param ftpHost  
     \*            FTP主机服务器  
     \* @param ftpPassword  
     \*            FTP 登录密码  
     \* @param ftpUserName  
     \*            FTP登录用户名  
     \* @param ftpPort  
     \*            FTP端口 默认为21  
     \* @return  
     \*/  
    public static FTPClient getFTPClient(String ftpHost, String ftpUserName,  
                                         String ftpPassword, int ftpPort) \{  
        FTPClient ftpClient = new FTPClient();  
        try \{  
            ftpClient = new FTPClient();  
            ftpClient.connect(ftpHost, ftpPort);// 连接FTP服务器  
            ftpClient.login(ftpUserName, ftpPassword);// 登陆FTP服务器  
            if (!FTPReply.isPositiveCompletion(ftpClient.getReplyCode())) \{  
                logger.info("未连接到FTP，用户名或密码错误。");  
                ftpClient.disconnect();  
            \} else \{  
                logger.info("FTP连接成功。");  
            \}  
        \} catch (SocketException e) \{  
            e.printStackTrace();  
            logger.info("FTP的IP地址可能错误，请正确配置。");  
        \} catch (IOException e) \{  
            e.printStackTrace();  
            logger.info("FTP的端口错误,请正确配置。");  
        \}  
        return ftpClient;  
    \}  
  
    /\*  
     \* 从FTP服务器下载文件  
     \*  
     \* @param ftpHost FTP IP地址  
     \*  
     \* @param ftpUserName FTP 用户名  
     \*  
     \* @param ftpPassword FTP用户名密码  
     \*  
     \* @param ftpPort FTP端口  
     \*  
     \* @param ftpPath FTP服务器中文件所在路径 格式： zq/ftp路劲    fdfd/aa  
     \*  
     \* @param localPath 下载到本地的位置 格式：H:/download  
     \*  
     \* @param fileName 文件名称  
     \*/  
    public static void downloadFtpFile(String ftpHost, String ftpUserName,  
                                       String ftpPassword, int ftpPort, String ftpPath, String localPath,  
                                       String fileName) \{  
  
        FTPClient ftpClient = null;  
  
        try \{  
            ftpClient = getFTPClient(ftpHost, ftpUserName, ftpPassword, ftpPort);  
            ftpClient.setControlEncoding("UTF-8"); // 中文支持  
            ftpClient.setFileType(FTPClient.BINARY\_FILE\_TYPE);  
            ftpClient.enterLocalPassiveMode();  
            ftpClient.changeWorkingDirectory(ftpPath);  
  
            File localFile = new File(localPath + File.separatorChar + fileName);  
            OutputStream os = new FileOutputStream(localFile);  
            ftpClient.retrieveFile(fileName, os);  
            os.close();  
            ftpClient.logout();  
  
        \} catch (FileNotFoundException e) \{  
            logger.error("没有找到" + ftpPath + "文件");  
            e.printStackTrace();  
        \} catch (SocketException e) \{  
            logger.error("连接FTP失败.");  
            e.printStackTrace();  
        \} catch (IOException e) \{  
            e.printStackTrace();  
            logger.error("文件读取错误。");  
            e.printStackTrace();  
        \}  
  
    \}  
  
  
  
\}  
  
3.测试（这一步测试其实是把文件从ftp上拉到（或复制到）本地自定义的文件夹下面）  
package com.zq.down;  
  
import com.zq.util.FtpUtil;  
  
/\*\*  
 \* Created by java1 on 2018/1/23 0023.  
 \*/  
public class FtpDownloadTestScriptTest \{  
    public static void main(String\[\] args) \{  
        String ftpHost = "10.1.1.123";  
        String ftpUserName = "123";  
        String ftpPassword = "123456";  
        int ftpPort = 21;  
        String ftpPath = "/";//ftp根目录  
        String localPath = "E:\\\\TestTxt";  
        String fileName = "c4.zip";  
        FtpUtil.downloadFtpFile(ftpHost, ftpUserName, ftpPassword, ftpPort, ftpPath, localPath, fileName);  
    \}

4. （1,2,3步骤是把文件拉到本地，如果说在界面想出现下载界面的话可以发送ajax请求。下面是我写的，仅供参考）  
        $.ajax(\{  
            type: 'POST',  
            dataType: 'json',  
            url: "/device/exportLog",  
            data: \{ 'deviceSn': deviceSn \} ,  
            timeout: 10000,  
            success: function ( data ) \{  
                if(data.status)\{  
                    Messenger().post(\{  
                        message: data.info,  
                        type: 'success',  
                        showCloseButton: true  
                    \}) ;  
                    var FileName = deviceSn.toLowerCase()+".zip";  
                    var url = window.location.protocol + "//" + window.location.host + "/device/deviceLogdownFromHttp?fileName="+FileName;  
                    window.location.href = url;  
                    \}else\{  
                    Messenger().post(\{  
                        message: data.info,  
                        type: 'error',  
                        showCloseButton: true  
                    \}) ;  
                \}  
            \}  
        \});  
  
5.后台：  
/\*\*  
     \* 下载zip文件  
     \* \*/  
    @RequestMapping("/deviceLogdownFromHttp")  
    public void deviceLogdownFromHttp(HttpServletRequest request, HttpServletResponse response)throws Exception\{  
        String fileName = request.getParameter("fileName");  
        try\{  
            String resultPath =PropertyUtil.getProperty("tasksave.filePath")+"/"+fileName;// "E://AllTxt//zqzipzipzipzipzip.rar";  
            String zipName = resultPath.substring(0,resultPath.lastIndexOf(".")) + ".zip";  
            File zipFile = new File(zipName);  
            //读写zip文件  
            InputStream fis = new BufferedInputStream(new FileInputStream(zipFile));  
            byte\[\] buffer = new byte\[fis.available()\];  
            fis.read(buffer);  
            fis.close();  
  
            response.reset();  
            String targetName = zipName.substring(zipName.lastIndexOf("/")+1);  
            targetName = new String(targetName.getBytes("UTF-8"), "ISO-8859-1");  
            response.setHeader("Content-Disposition", "attachment; filename=\\"" + targetName + "\\"");  
            response.addHeader("Content-lenth", "" + buffer.length);  
            response.setContentType("application/octet-stream;charset=UTF-8");  
  
            OutputStream os = new BufferedOutputStream(response.getOutputStream());  
            os.write(buffer);  
            os.flush();  
            os.close();  
            response.flushBuffer();  
    String cc=fileName.substring(0,fileName.lastIndexOf(".")).toUpperCase();  
            sysLogMapper.deleteDownloadLogTaskByDeviceSn(fileName.substring(0,fileName.lastIndexOf(".")).toUpperCase());  
        \}catch(Exception e)\{  
            e.printStackTrace();  
        \}  
  
  
  
    \}  
6.（4,5步骤仅供参考，每个人写的不一样。）  
      主要是：  
                    var FileName = deviceSn.toLowerCase()+".zip";  
                    var url = window.location.protocol + "//" + window.location.host + "/device/deviceLogdownFromHttp?fileName="+FileName;  
                    window.location.href = url;（前台）  
    (后台):deviceLogdownFromHttp这个方法