解决小程序图片打包过大，放置后端，不引用ngnix、minio等组件，还能进行权限校验

package com.huida.web.controller.common.app;

import com.huida.common.core.controller.BaseController;
import com.huida.common.utils.file.FileUtils;
import lombok.RequiredArgsConstructor;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.core.io.Resource;
import org.springframework.core.io.ResourceLoader;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import javax.servlet.http.HttpServletResponse;
import java.io.IOException;


@RestController
@RequiredArgsConstructor
@RequestMapping("/static")
public class StaticResourcesController extends BaseController {

    @Autowired
    private ResourceLoader resourceLoader;

    @GetMapping("/img/train/{fileName}")
    public void getImgTrain(@PathVariable String fileName, HttpServletResponse response) throws IOException {
        Resource resource = resourceLoader.getResource("classpath:static/img/train/" + fileName);
        if (resource.exists()) {
            response.setContentType(FileUtils.getContentType(resource.getFilename()));
            FileUtils.writeBytes(resource.getURI().getPath(), response.getOutputStream());
        }
    }

    @GetMapping("/img/{fileName}")
    public void getImg(@PathVariable String fileName, HttpServletResponse response) throws IOException {
        Resource resource = resourceLoader.getResource("classpath:static/img/" + fileName);
        if (resource.exists()) {
            response.setContentType(FileUtils.getContentType(resource.getFilename()));
            FileUtils.writeBytes(resource.getURI().getPath(), response.getOutputStream());
        }
    }

}

  /**
     * 根据文件名，设置HttpServletResponse的ContentType
     *
     * @param fileName 文件名
     * @return 结果
     * @author weimingzhong
     * @date 2024/4/3 9:50
     */
    public static String getContentType(String fileName) {
        String fileExtension = getFileExtension(fileName);
        switch (fileExtension) {
            case "png":
                return MediaType.IMAGE_PNG_VALUE;
            case "jpg":
            case "jpeg":
                return MediaType.IMAGE_JPEG_VALUE;
            case "gif":
                return MediaType.IMAGE_GIF_VALUE;
            case "pdf":
                return MediaType.APPLICATION_PDF_VALUE;
            // Add more cases for other file types if needed
            default:
                return MediaType.APPLICATION_OCTET_STREAM_VALUE; // Default to octet-stream
        }
    }

    private static String getFileExtension(String fileName) {
        int dotIndex = fileName.lastIndexOf(".");
        if (dotIndex > 0 && dotIndex < fileName.length() - 1) {
            return fileName.substring(dotIndex + 1).toLowerCase();
        } else {
            return "";
        }
    }