流程

• avatar_dir：请求图片在服务端的存放路径
• user.dir：项目根目录
  

效果

静态资源访问

1. application.yml
   设置静态文件存储路径

   custom:
     upload:
       avatar_dir: ${user.dir}/avatar_dir/
       avatar_dir_name: avatar_dir
   

2. FileUploadConfig
   application.yml 信息读取配置类

   @Data
   @Configuration
   @ConfigurationProperties(prefix = "custom.upload")
   public class FileUploadConfig {
      private String avatarDir;
      private String avatarDirName;
   }
   

3. 静态资源访问配置类

   @Configuration
   public class WebConfig implements WebMvcConfigurer {
       @Autowired
       FileUploadConfig uploadConfig;
   
       @Override
       public void addResourceHandlers(ResourceHandlerRegistry registry) {
           File file = new File(uploadConfig.getAvatarDir());
           String path = "file:" + file + File.separator;
           // 匹配 http://ip:port/avatar_dir/ 下的所有文件
           registry.addResourceHandler("/avatar_dir/**")
                   // 实际静态文件地址
                   .addResourceLocations(path);
       }
   }
   

Service

@Service
public interface FileService {
	// 获取图像 Url
    public Result<String> getImageUrl(User user, String host, int port);
	// 路径拼接
    public String joinPaths(String... paths);
}

ServiceImpl

• http://ip:port/静态文件存储路径/文件名

  String imageUrl = String.format(
  	"http://%s:%d/%s", host, port, joinPaths(
    								  		uploadConfig.getAvatarDirName(), 
    								  		avatar
    							  		)
  );
  

• 实现代码

  @Service
  public class FileServiceImpl implements FileService {
      @Autowired
      FileUploadConfig uploadConfig;
  
      @Autowired
      IUserService userService;
  
  	// 路径拼接
      @Override
      public String joinPaths(String... paths) {
          Path resultPath = Paths.get("");
          for (String path : paths) {
              resultPath = resultPath.resolve(path);
          }
          return resultPath.toString();
      }
      
      // 判断文件是否存在
      private Boolean isUserAvatarExists(String avatar) {
          String path = joinPaths(uploadConfig.getAvatarDir(), avatar);
          File filePath = new File(path);
          return filePath.exists();
      }
  
  	// 获取图像 Url
      @Override
      public Result<String> getImageUrl(User user, String host, int port) {
      	// 用户头像的文件名唯一，并保存在了数据库中，avatar = xxx.png
          String avatar = this.userService.getById(user.getUserId()).getAvatar();
          
          if (isUserAvatarExists(avatar)) {
              String imageUrl = String.format("http://%s:%d/%s", host, port, joinPaths(uploadConfig.getAvatarDirName(), avatar));
              return Result.successfulResult("获取成功", imageUrl);
          }
          return Result.errorResult("文件丢失");
      }
  }
  

Controller

@Tag(name = "文件上传接口")
@RestController
@RequestMapping("/sign/file")
public class FileUploadController {
    @Autowired
    FileService fileService;

    @Operation(summary = "获取图片 URL")
    @PostMapping("/image/get")
    public Result<String> getImageUrl(@RequestBody User user) {
        URI currentUri = ServletUriComponentsBuilder.fromCurrentRequestUri().build().toUri();
        // currentUri.getHost() 获取请求 IP，如 localhost
        // currentUri.getPort() 获取请求 端口号，如 8080
        return fileService.getImageUrl(user, currentUri.getHost(), currentUri.getPort());
    }
}