小练习：Springboot上传文件

项目结构：

创建一个包含web与Thymleaf依赖的springboot项目

application.properties

# 上传文件总最大值
spring.servlet.multipart.max-request-size=20MB
# 上传单个文件最大值
spring.servlet.multipart.max-file-size=20MB

#存储路径
file.upload.dir = f:/test/week02/

#页面路径前后缀
spring.mvc.view.prefix=classpath:/templates/
spring.mvc.view.suffix=.html

1、控制层controller

ImageController

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
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;

import java.io.File;
import java.io.IOException;

@Controller
public class ImageController {
    private static final Logger LOGGER = LoggerFactory.getLogger(ImageController.class);

    @Value("${file.upload.dir}")
    private String uploadFilePath;

    @GetMapping("/upload")
    public String upload() {
        return "upload";
    }

    @ResponseBody
    @PostMapping("/upload")
    public String upload(@RequestParam("file") MultipartFile file){
        if (file.isEmpty()) {
            return "上传失败，请选择文件";
        }

        //文件名
        String fileName = file.getOriginalFilename();
        File dest = new File(uploadFilePath + fileName);

        //检测目录是否存在
        if (!dest.getParentFile().exists()){
            dest.getParentFile().mkdirs();
        }

        //检测文件是否存在
        if(dest.exists()){
           return "文件已经存在";
        }

        try {
            file.transferTo(dest);
            LOGGER.info("上传成功");
            return "上传成功";
        } catch (IOException e) {
            LOGGER.error(e.toString(), e);
        }
        return "上传失败！";

    }
}

2、html页面

localhost:8080/upload