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Spring Boot应用实现图片资源服务

news 2025/8/20 8:37:36

在这篇文章中，我们将介绍如何使用Spring Boot创建一个REST API来提供服务器上的静态图片资源。该API包括路径安全检查、文件存在性验证以及缓存控制等功能，并且代码包含详细的注释以帮助理解。

Maven依赖

首先，在您的pom.xml文件中添加以下依赖项：

<dependencies><!-- Spring Boot Starter Web for building web applications --><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId></dependency><!-- Lombok to reduce boilerplate code --><dependency><groupId>org.projectlombok</groupId><artifactId>lombok</artifactId><scope>provided</scope></dependency><!-- For logging --><dependency><groupId>org.slf4j</groupId><artifactId>slf4j-api</artifactId></dependency>
</dependencies>

确保您已经正确配置了Maven项目的其他部分，如<parent>标签和版本管理等。

Java代码

接下来是核心Java代码，位于package pub.qingyun.web;包下：

package pub.qingyun.web;import lombok.extern.slf4j.Slf4j;
import org.springframework.core.io.UrlResource;
import org.springframework.http.HttpHeaders;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.CrossOrigin;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;import java.net.MalformedURLException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;@RestController
@CrossOrigin
@Slf4j
public class ImageController {// 图片根目录private static final Path IMAGE_ROOT = Paths.get("F:", "Temp").toAbsolutePath().normalize();/*** 获取图片资源并返回给客户端** @param imagePath 图片文件的相对路径参数* @return ResponseEntity<UrlResource> 包含图片资源的响应实体，包含适当的HTTP状态码和响应头*/@GetMapping("/showImage")public ResponseEntity<UrlResource> getImage(@RequestParam String imagePath) {long start = System.currentTimeMillis();// 参数校验：检查图片路径是否为空if (imagePath == null || imagePath.trim().isEmpty()) {log.warn("Missing imagePath parameter");return ResponseEntity.badRequest().build();}// 路径安全检查：防止路径遍历攻击// 过滤非法字符，防止路径穿越if (imagePath.contains("..") || imagePath.contains("\\") || imagePath.startsWith("/")) {log.warn("Forbidden path access attempt: [PATH_REDACTED]");return ResponseEntity.status(403).build();}Path resolvedPath = IMAGE_ROOT.resolve(imagePath).normalize();if (!resolvedPath.startsWith(IMAGE_ROOT)) {log.warn("Forbidden path access attempt: [PATH_REDACTED]");return ResponseEntity.status(403).build();}// 文件存在性检查：验证文件是否存在且为常规文件if (!Files.exists(resolvedPath) || !Files.isRegularFile(resolvedPath)) {log.info("Image not found: [PATH_REDACTED]");return ResponseEntity.notFound().build();}// 缓存文件长度，避免重复调用long fileLength = resolvedPath.toFile().length();// 创建资源对象UrlResource resource;try {resource = new UrlResource(resolvedPath.toUri());} catch (MalformedURLException e) {log.error("Failed to create resource for: [PATH_REDACTED], Malformed URL", e);return ResponseEntity.status(500).build();} catch (Exception e) {log.error("Failed to create resource for: [PATH_REDACTED]", e);return ResponseEntity.status(500).build();}// 设置响应头信息HttpHeaders headers = new HttpHeaders();headers.setCacheControl("public, max-age=86400"); // 缓存 1 天headers.setExpires(System.currentTimeMillis() + 86400_000L); // 过期时间headers.setContentDispositionFormData("inline", resource.getFilename());log.info("getImage [PATH_REDACTED] ({} bytes) cost: {}ms", fileLength, (System.currentTimeMillis() - start));// 构建并返回成功响应return ResponseEntity.ok().headers(headers).contentType(MediaType.IMAGE_JPEG).contentLength(fileLength).body(resource);}
}