7.2 SpringBoot实现上传图片API + url映射本地路径registry.addResourceHandler

在Spring Boot中实现上传图片的API并将URL映射到本地路径，可以使用MultipartFile接收上传的文件，并使用ResourceHandlerRegistry将映射URL设置为本地路径。以下是一个简单的例子：

1. 添加依赖（通常Spring Boot Starter Web已经包含了Spring MVC，所以不需要额外添加）：

<!-- 如果使用Maven，请确保已经包含Spring Boot Starter Web -->

2. 创建一个控制器来处理文件上传：

import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.multipart.MultipartFile;
 
@Controller
public class ImageUploadController {
 
    private static final String UPLOAD_DIR = "/path/to/upload/dir"; // 设置上传文件夹路径
 
    @PostMapping("/upload")
    public @ResponseBody String handleFileUpload(@RequestParam("file") MultipartFile file) {
        try {
            String filename = file.getOriginalFilename();
            String filePath = UPLOAD_DIR + "/" + filename;
            file.transferTo(new File(filePath));
            return "File uploaded successfully: " + filePath;
        } catch (Exception e) {
            e.printStackTrace();
            return "File upload failed: " + e.getMessage();
        }
    }
}

3. 配置ResourceHandler以映射URL到本地路径：

import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.ResourceHandlerRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
 
@Configuration
public class WebConfig implements WebMvcConfigurer {
 
    @Override
    public void addResourceHandlers(ResourceHandlerRegistry registry) {
        registry.addResourceHandler("/images/**")
                .addResourceLocations("file:" + UPLOAD_DIR + "/");
    }
}

4. 访问API：

上传图片：

POST /upload HTTP/1.1
Content-Disposition: form-data; name="file"; filename="example.jpg"
Content-Type: image/jpeg
 
[file content]

映射本地路径访问图片：

GET /images/example.jpg HTTP/1.1

以上代码实现了一个简单的文件上传API，并将上传的图片映射到本地路径以供访问。记得替换UPLOAD_DIR为实际的上传文件夹路径。