java文件上传到服务器（SpringBoot实现文件上传）|快速备案

一、SpringBoot模拟文件上传，下载上传：文件前端传入，后端获取到文件通过输出流写入文件下载：获取到文件路径，通过输入流读取，在通过输出流写入文件实现下载#文件上传大小配置单个文件大小总的文件大小
spring.servlet.multipart.max-file-size=10MB
spring.servlet.multipart.max-request-size=100MB

<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>

import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Controller;
import org.springframework.util.ClassUtils;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.multipart.MultipartFile;

import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletResponse;
import java.io.*;
import java.net.URLEncoder;

/**
* @author: 清峰
* @date: 2020/11/1 18:31
* @code: 愿世间永无Bug!
* @description: 文件上传与下载 (伪下载文件读写的过程)
* 上传：文件前端传入，后端获取到文件通过输出流写入文件
* 下载：获取到文件路径，通过输入流读取，在通过输出流写入文件实现下载
*
* 真正实现文件上传服务器（使用ftp协议文件传输协议网络访问传输协议）
* 也可以获取项目的相对路径在项目下（项目部署在了服务器上）创建一个文件夹用于保存文件，上传的文件保存在项目路径下即可（还可以将路径保存到数据库中http://localhost:8080/file/XXX）
* 下载的话：前端文件名展示，指定文件下载获取到文件名，找到路径进行文件读取写入到客户端
*/
@Slf4j //lombok提供的日志注解可直接调用 log的方法
@Controller
@RequestMapping("/file")
public class FileUploadController {

    @PostMapping("/upload")
    public void upload(@RequestParam("file") MultipartFile file) throws IOException {
//        String realPath = req.getSession().getServletContext().getRealPath("/uploadFile");
        // 放在static下的原因是，存放的是静态文件资源，即通过浏览器输入本地服务器地址，加文件名时是可以访问到的
//        String path = ClassUtils.getDefaultClassLoader().getResource("").getPath()+"static/";
        File targetFile = new File("C:\\Users\\ASUS\\Desktop\\file");
        if (!targetFile.exists()) {
            targetFile.mkdirs();
        }
        FileOutputStream bos = null;
        try {
            String str = targetFile + "\\" + file.getOriginalFilename();    //C:\Users\ASUS\Desktop\file\bg.jpg
            log.info(str);
            bos = new FileOutputStream(str);//FileOutputStream读取流的时候如果是文件夹，就会出错，无论怎么读，都拒绝访问，应该在读取的目录后面加上文件名
            bos.write(file.getBytes()); //前端文件传过来后端将文件通过流写入文件夹中

        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } finally {
            bos.flush();
            bos.close();
        }
        log.info("上传成功");
    }

    @GetMapping("/download")
    public void download(HttpServletResponse response) throws IOException {
        FileInputStream fis = null;
        ServletOutputStream os = null;
        try {
            String filename = "bg.jpg";
            String filePath = "C:\\Users\\ASUS\\Desktop\\file\\" + filename;
            File file = new File(filePath);

            if (file.exists()) {
                //响应头的下载内容格式
                response.setContentType("application/octet-stream");
                response.setHeader("content-type", "application/octet-stream");
                response.setHeader("Content-Disposition", "attachment;fileName=" + URLEncoder.encode(filename, "utf8"));

fis = new FileInputStream(file);
byte[] bytes = new byte[1024];

                os = response.getOutputStream();
//                FileOutputStream os = new FileOutputStream(new File("C:\\Users\\ASUS\\Desktop\\"+filename));
                int i = fis.read(bytes);    //从文件夹中读取文件通过流写入指定文件中
                while (i != -1) {
                    os.write(bytes);
                    i = fis.read(bytes);
                }

}

        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            os.close();
            fis.close();
        }
        log.info("下载成功");
    }
}

二、SpringBoot实现文件上传至远程服务器（ftp）FTP服务器（File Transfer Protocol Server）是在互联网上提供文件存储和访问服务的计算机，它们依照FTP协议提供服务。FTP是File Transfer Protocol(文件传输协议)。顾名思义，就是专门用来传输文件的协议。简单地说，支持FTP协议的服务器就是FTP服务器。FTP是用来在两台计算机之间传输文件，是Internet中应用非常广泛的服务之一。它可根据实际需要设置各用户的使用权限，同时还具有跨平台的特性，快速方便地上传、下载文件。  <!– Apache 的 common-net  是 commos 顶级项目下一个非常强大的用于网络编程的子项目 –>
        <dependency>
            <groupId>commons-net</groupId>
            <artifactId>commons-net</artifactId>
            <version>3.6</version>
        </dependency>
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.17</version>
        </dependency>

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.TimeZone;

import org.apache.commons.net.ftp.FTPClient;
import org.apache.commons.net.ftp.FTPClientConfig;
import org.apache.commons.net.ftp.FTPFile;
import org.apache.commons.net.ftp.FTPReply;

import org.apache.log4j.Logger;

/**
* @author: 清峰
* @date: 2020/11/2 9:30
* @code: 愿世间永无Bug!
* @description:
*/

public class Ftp {
    private FTPClient ftpClient;
    private String strIp;
    private int intPort;
    private String user;
    private String password;

private static Logger logger = Logger.getLogger(Ftp.class.getName());

    /* *
     * Ftp构造函数
     */
    public Ftp(String strIp, int intPort, String user, String Password) {
        this.strIp = strIp;
        this.intPort = intPort;
        this.user = user;
        this.password = Password;
        this.ftpClient = new FTPClient();
    }

    /**
     * @return 判断是否登入成功
     */
    public boolean ftpLogin() {
        boolean isLogin = false;
        FTPClientConfig ftpClientConfig = new FTPClientConfig();
        ftpClientConfig.setServerTimeZoneId(TimeZone.getDefault().getID());
        this.ftpClient.setControlEncoding("GBK");
        this.ftpClient.configure(ftpClientConfig);
        try {
            if (this.intPort > 0) {
                this.ftpClient.connect(this.strIp, this.intPort);
            } else {
                this.ftpClient.connect(this.strIp);
            }
            // FTP服务器连接回答
            int reply = this.ftpClient.getReplyCode();
            if (!FTPReply.isPositiveCompletion(reply)) {
                this.ftpClient.disconnect();
                logger.error("登录FTP服务失败！");
                return isLogin;
            }
            this.ftpClient.login(this.user, this.password);
            // 设置传输协议
            this.ftpClient.enterLocalPassiveMode();
            this.ftpClient.setFileType(FTPClient.BINARY_FILE_TYPE);
            logger.info("恭喜" + this.user + "成功登陆FTP服务器");
            isLogin = true;
        } catch (Exception e) {
            e.printStackTrace();
            logger.error(this.user + "登录FTP服务失败！" + e.getMessage());
        }
        this.ftpClient.setBufferSize(1024 * 2);
        this.ftpClient.setDataTimeout(30 * 1000);
        return isLogin;
    }

    /**
     * @退出关闭服务器链接
     */
    public void ftpLogOut() {
        if (null != this.ftpClient && this.ftpClient.isConnected()) {
            try {
                boolean reuslt = this.ftpClient.logout();// 退出FTP服务器
                if (reuslt) {
                    logger.info("成功退出服务器");
                }
            } catch (IOException e) {
                e.printStackTrace();
                logger.warn("退出FTP服务器异常！" + e.getMessage());
            } finally {
                try {
                    this.ftpClient.disconnect();// 关闭FTP服务器的连接
                } catch (IOException e) {
                    e.printStackTrace();
                    logger.warn("关闭FTP服务器的连接异常！");
                }
            }
        }
    }

    /***
     * 上传Ftp文件
     * @param localFile 当地文件
     * romotUpLoadePath上传服务器路径 – 应该以/结束
     * */
    public boolean uploadFile(File localFile, String romotUpLoadePath) {
        BufferedInputStream inStream = null;
        boolean success = false;
        try {
            this.ftpClient.changeWorkingDirectory(romotUpLoadePath);// 改变工作路径
            inStream = new BufferedInputStream(new FileInputStream(localFile));
            logger.info(localFile.getName() + "开始上传…..");
            success = this.ftpClient.storeFile(localFile.getName(), inStream);
            if (success == true) {
                logger.info(localFile.getName() + "上传成功");
                return success;
            }
        } catch (FileNotFoundException e) {
            e.printStackTrace();
            logger.error(localFile + "未找到");
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (inStream != null) {
                try {
                    inStream.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
        return success;
    }

    /***
     * 下载文件
     * @param remoteFileName   待下载文件名称
     * @param localDires 下载到当地那个路径下
     * @param remoteDownLoadPath remoteFileName所在的路径
     * */

    public boolean downloadFile(String remoteFileName, String localDires,
                                String remoteDownLoadPath) {
        String strFilePath = localDires + remoteFileName;
        BufferedOutputStream outStream = null;
        boolean success = false;
        try {
            this.ftpClient.changeWorkingDirectory(remoteDownLoadPath);
            outStream = new BufferedOutputStream(new FileOutputStream(
                    strFilePath));
            logger.info(remoteFileName + "开始下载….");
            success = this.ftpClient.retrieveFile(remoteFileName, outStream);
            if (success == true) {
                logger.info(remoteFileName + "成功下载到" + strFilePath);
                return success;
            }
        } catch (Exception e) {
            e.printStackTrace();
            logger.error(remoteFileName + "下载失败");
        } finally {
            if (null != outStream) {
                try {
                    outStream.flush();
                    outStream.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
        if (success == false) {
            logger.error(remoteFileName + "下载失败!!!");
        }
        return success;
    }

    /***
     * @上传文件夹
     * @param localDirectory
     *            当地文件夹
     * @param remoteDirectoryPath
     *            Ftp 服务器路径以目录"/"结束
     * */
    public boolean uploadDirectory(String localDirectory,
                                   String remoteDirectoryPath) {
        File src = new File(localDirectory);
        try {
            remoteDirectoryPath = remoteDirectoryPath + src.getName() + "/";
            this.ftpClient.makeDirectory(remoteDirectoryPath);
            // ftpClient.listDirectories();
        } catch (IOException e) {
            e.printStackTrace();
            logger.info(remoteDirectoryPath + "目录创建失败");
        }
        File[] allFile = src.listFiles();
        for (int currentFile = 0; currentFile < allFile.length; currentFile++) {
            if (!allFile[currentFile].isDirectory()) {
                String srcName = allFile[currentFile].getPath().toString();
                uploadFile(new File(srcName), remoteDirectoryPath);
            }
        }
        for (int currentFile = 0; currentFile < allFile.length; currentFile++) {
            if (allFile[currentFile].isDirectory()) {
                // 递归
                uploadDirectory(allFile[currentFile].getPath().toString(),
                        remoteDirectoryPath);
            }
        }
        return true;
    }

    /***
     * @下载文件夹
     * @param
     * @param remoteDirectory 远程文件夹
     * */
    public boolean downLoadDirectory(String localDirectoryPath, String remoteDirectory) {
        try {
            String fileName = new File(remoteDirectory).getName();
            localDirectoryPath = localDirectoryPath + fileName + "//";
            new File(localDirectoryPath).mkdirs();
            FTPFile[] allFile = this.ftpClient.listFiles(remoteDirectory);
            for (int currentFile = 0; currentFile < allFile.length; currentFile++) {
                if (!allFile[currentFile].isDirectory()) {
                    downloadFile(allFile[currentFile].getName(), localDirectoryPath, remoteDirectory);
                }
            }
            for (int currentFile = 0; currentFile < allFile.length; currentFile++) {
                if (allFile[currentFile].isDirectory()) {
                    String strremoteDirectoryPath = remoteDirectory + "/" + allFile[currentFile].getName();
                    downLoadDirectory(localDirectoryPath, strremoteDirectoryPath);
                }
            }
        } catch (IOException e) {
            e.printStackTrace();
            logger.info("下载文件夹失败");
            return false;
        }
        return true;
    }

    // FtpClient的Set 和 Get 函数
    public FTPClient getFtpClient() {
        return ftpClient;
    }

    public void setFtpClient(FTPClient ftpClient) {
        this.ftpClient = ftpClient;
    }

    public static void main(String[] args) throws IOException {
        Ftp ftp = new Ftp("10.3.15.1", 21, "ghips", "ghipsteam");
        ftp.ftpLogin();
        //上传文件夹
        ftp.uploadDirectory("d://DataProtemp", "/home/data/");
        //下载文件夹
        ftp.downLoadDirectory("d://tmp//", "/home/data/DataProtemp");
        ftp.ftpLogOut();
    }
}