package com.sky.utils;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.UUID;
import org.springframework.util.FileCopyUtils;
import org.springframework.util.ResourceUtils;
import org.springframework.web.multipart.MultipartFile;
public class UploadFileUtil {
    /**
     * 獲取文件保存路徑
     *
     * @return File
     * @throws FileNotFoundException
     */
    static List<File> getUploadDirectory() throws FileNotFoundException {
        // 開發(fā)環(huán)境獲取 target/classes 目錄：清理重新編譯后就沒有了
        File targetPath = new File(ResourceUtils.getURL("classpath:").getPath());
        // System.out.printf("項目運行的絕對路徑：" + path.getAbsolutePath());
        // 輸出 xx/sky-parent/sky-server/target/classes
        // 生產(chǎn)環(huán)境 不存在 target/classes 目錄
        if (!targetPath.exists()) {
            // 獲取當前運行目錄
            targetPath = new File("");
        }
        // 開發(fā)環(huán)境 resources 目錄：可永久保存
        String resourcesPath = System.getProperty("user.dir") + "/sky-server/src/main/resources";
        // System.out.printf("resources目錄路徑：" + resourcesPath);
        File path = new File(resourcesPath);
        File upload = new File(path.getAbsolutePath(), "upload");
        File uploadTarget = new File(targetPath.getAbsolutePath(), "upload");
        // 不存在則創(chuàng)建
        if (!upload.exists()) {
            upload.mkdirs();
        }
        if (!uploadTarget.exists()) {
            uploadTarget.mkdirs();
        }
        List<File> files = new ArrayList<File>();
        files.add(upload);
        files.add(uploadTarget);
        // System.out.printf("當前目錄：" + files);
        return files;
    }
    public static String upload(MultipartFile myFile, String dir) throws IOException {
        String filePath = "";
        if (!myFile.isEmpty()) {
            try {
                String filename = myFile.getOriginalFilename();
                filename = UUID.randomUUID() + filename.substring(filename.lastIndexOf("."));
                // 之所以保存到 resources 和 target 兩個目錄，兼顧開發(fā)測試和永久保存
                // 只保存到resources目錄下每次上傳了要重新編譯下，target則清理打包后就沒有了
                List<File> files = getUploadDirectory();
                // 注意這里一個文件不能循環(huán)同時寫入多個目錄，保存了第一個，第二個要復制過去
                File curFile = new File(files.get(0), filename);
                myFile.transferTo(curFile);
                FileCopyUtils.copy(curFile, new File(files.get(1), filename));
                //for (File f: files) {
                    //File curFile = new File(f, filename);
                    //myFile.transferTo(curFile);
                //}
                filePath = "http://localhost:8080/upload/" + filename;
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        return filePath;
    }
}

server:
  port: 8080
spring:
  mvc:
    static-path-pattern: /upload/**

package com.sky.config;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.ResourceHandlerRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurationSupport;
import java.util.List;
/**
 * 配置類，注冊web層相關組件
 */
@Configuration
public class WebMvcConfiguration extends WebMvcConfigurationSupport {
    /**
     * 設置靜態(tài)資源映射
     * @param registry
     */
    protected void addResourceHandlers(ResourceHandlerRegistry registry) {
        // 設置上傳的文件靜態(tài)資源映射，application 里的 mvc 里也要設置下靜態(tài)目錄
        registry.addResourceHandler("/upload/**")
                .addResourceLocations("classpath:/upload/", "file:upload/");
    }
}

package com.sky.controller.common;
import com.sky.result.Result;
import com.sky.utils.UploadFileUtil;
import io.swagger.annotations.Api;
import io.swagger.annotations.ApiOperation;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.multipart.MultipartFile;
import java.io.IOException;
/**
 * 公共請求
 */
@RestController
@RequestMapping("/common")
@Api(tags = "公共")
@Slf4j
public class CommonController {
    @PostMapping("/upload")
    @ApiOperation("上傳文件")
    public Result uploadFile(MultipartFile file) throws IOException {
        log.info("上傳文件：{}", file);
        String fileUrl = UploadFileUtil.upload(file, "");
        if (fileUrl == null || fileUrl == "") {
            return Result.error("上傳失敗");
        }
        return Result.success(fileUrl);
    }
}