Spring Boot文件上传

如何上传

Controller

@RequestMapping(value = "upload/image", method = RequestMethod.POST)
public ResponseVO uploadImage(@RequestParam("file") MultipartFile file, HttpServletResponse response, HttpServletRequest request) {
	FileUtil.saveFile("/local/image/", name, file.getBytes());
}

FileUtil工具类

package com.dongbawen.common.util;

import com.alibaba.fastjson.util.IOUtils;
import com.google.common.base.Preconditions;
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.lang3.ArrayUtils;
import org.apache.commons.lang3.StringUtils;

import javax.servlet.http.HttpServletResponse;
import java.io.*;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.util.Arrays;
import java.util.zip.CRC32;
import java.util.zip.CheckedOutputStream;
import java.util.zip.ZipEntry;
import java.util.zip.ZipOutputStream;

@Slf4j
public class FileUtil {

    private static final int BUFFER = 1024 * 8;

    /**
     * 允许下载的文件类型，根据需求自己添加（小写）
     */
    public static final String[] VALID_FILE_TYPE = {"xlsx", "zip"};

    /**
     * 压缩文件或目录
     *
     * @param fromPath 待压缩文件或路径
     * @param toPath   压缩文件，如 xx.zip
     */
    public static void compress(String fromPath, String toPath) throws IOException {
        File fromFile = new File(fromPath);
        File toFile = new File(toPath);
        if (!fromFile.exists()) {
            throw new FileNotFoundException(fromPath + "不存在！");
        }
        try (
                FileOutputStream outputStream = new FileOutputStream(toFile);
                CheckedOutputStream checkedOutputStream = new CheckedOutputStream(outputStream, new CRC32());
                ZipOutputStream zipOutputStream = new ZipOutputStream(checkedOutputStream)
        ) {
            String baseDir = "";
            compress(fromFile, zipOutputStream, baseDir);
        }
    }

    /**
     * 文件下载
     *
     * @param filePath 待下载文件路径
     * @param fileName 下载文件名称
     * @param delete   下载后是否删除源文件
     * @param response HttpServletResponse
     * @throws Exception Exception
     */
    public static void download(String filePath, String fileName, Boolean delete, HttpServletResponse response) throws Exception {
        File file = new File(filePath);
        if (!file.exists()) {
            throw new Exception("文件未找到");
        }

        String fileType = getFileType(file);
        if (!fileTypeIsValid(fileType)) {
            throw new Exception("暂不支持该类型文件下载");
        }
        response.setHeader("Content-Disposition", "attachment;fileName=" + java.net.URLEncoder.encode(fileName, "utf-8"));
        response.setContentType("multipart/form-data");
        response.setCharacterEncoding("utf-8");
        try (InputStream inputStream = new FileInputStream(file); OutputStream os = response.getOutputStream()) {
            byte[] b = new byte[2048];
            int length;
            while ((length = inputStream.read(b)) > 0) {
                os.write(b, 0, length);
            }
        } finally {
            if (delete) {
                delete(filePath);
            }
        }
    }

    /**
     * 递归删除文件或目录
     *
     * @param filePath 文件或目录
     */
    public static void delete(String filePath) {
        File file = new File(filePath);
        if (file.isDirectory()) {
            File[] files = file.listFiles();
            if (files != null) {
                Arrays.stream(files).forEach(f -> delete(f.getPath()));
            }
        }
        try {
            Files.delete(Paths.get(filePath));
        } catch (IOException e) {
            log.error("删除失败", e);
        }
    }

    /**
     * 获取文件类型
     *
     * @param file 文件
     * @return 文件类型
     * @throws Exception Exception
     */
    private static String getFileType(File file) throws Exception {
        Preconditions.checkNotNull(file);
        if (file.isDirectory()) {
            throw new Exception("file不是文件");
        }
        String fileName = file.getName();
        return fileName.substring(fileName.lastIndexOf(".") + 1);
    }


    /**
     * 校验文件类型是否是允许下载的类型
     * （出于安全考虑：https://github.com/wuyouzhuguli/FEBS-Shiro/issues/40）
     *
     * @param fileType fileType
     * @return Boolean
     */
    private static Boolean fileTypeIsValid(String fileType) {
        Preconditions.checkNotNull(fileType);
        fileType = StringUtils.lowerCase(fileType);
        return ArrayUtils.contains(VALID_FILE_TYPE, fileType);
    }

    private static void compress(File file, ZipOutputStream zipOut, String baseDir) throws IOException {
        if (file.isDirectory()) {
            compressDirectory(file, zipOut, baseDir);
        } else {
            compressFile(file, zipOut, baseDir);
        }
    }

    private static void compressDirectory(File dir, ZipOutputStream zipOut, String baseDir) throws IOException {
        File[] files = dir.listFiles();
        if (files != null && ArrayUtils.isNotEmpty(files)) {
            for (File file : files) {
                compress(file, zipOut, baseDir + dir.getName() + "/");
            }
        }
    }

    private static void compressFile(File file, ZipOutputStream zipOut, String baseDir) throws IOException {
        if (!file.exists()) {
            return;
        }
        try (BufferedInputStream bis = new BufferedInputStream(new FileInputStream(file))) {
            ZipEntry entry = new ZipEntry(baseDir + file.getName());
            zipOut.putNextEntry(entry);
            int count;
            byte[] data = new byte[BUFFER];
            while ((count = bis.read(data, 0, BUFFER)) != -1) {
                zipOut.write(data, 0, count);
            }
        }
    }

    public static String saveFile(String path,String fileName, byte[] bytes) throws Exception {
        FileOutputStream fileOutputStream = null;
        BufferedOutputStream bufferedOutputStream = null;
        try {
            if (!new File(path).exists()) {
                new File(path).mkdirs();
            }
            String filePath = path + fileName;
            fileOutputStream = new FileOutputStream(new File(filePath));
            bufferedOutputStream = new BufferedOutputStream(fileOutputStream);
            bufferedOutputStream.write(bytes);
            return fileName;
        } finally {
            IOUtils.close(bufferedOutputStream);
            IOUtils.close(fileOutputStream);
        }
    }
}

由于FileUtil依赖fastjson，所以需要在pom中引入这个jar

<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>fastjson</artifactId>
    <version>1.2.31</version>
</dependency>

这样就可以把文件上传到指定的目录了，上文中的上传路径为/local/image/，这个表示你项目所在磁盘的根目录。

如何访问

如果是上传到项目目录下访问倒是比较好访问，但是上传到项目目录下每次部署项目的时候为免太麻烦了，如果像问中这种上传到某个与项目无关的目录（比如E盘根目录下）那么怎么访问呢？需要做如下配置

spring:
	resources:
    #资源存放的磁盘位置
    static-locations: classpath:/static,classpath:/public,classpath:/resources,classpath:/META-INF/resource,file:E://local//image/

这个意思代表，当我们查找静态资源的时候，依次按照上诉路径去查找，知道找到为止。
关于springboot的静态资源加载顺序可以参考这篇文章

报错

这样设置当上传图片或者文件大于1MB的时候会报错

The field file exceeds its maximum permitted size of 1048576 bytes.

这是因为Spring Boot规定，每个文件的配置最大为1Mb，单次请求的文件的总数不能大于10Mb。要更改这个默认值需要在配置文件（如application.properties）中加入两个配置
Spring Boot2.0之后的版本配置为:

spring.servlet.multipart.max-file-size = 10MB  
spring.servlet.multipart.max-request-size=100MB

要不限制设置成-1，如下

spring:
	servlet:
	    multipart:
	      max-file-size: -1
	      max-request-size: -1