How to implement SpringBoot file upload function-javaTutorial-php.cn

How to implement SpringBoot file upload function

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Release： 2023-05-17 12:15:36

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1. Application example

Requirements: Demonstrate Spring-Boot to register users through forms and support uploading pictures

2. Code implementation

Code implementation-file upload

Please create templates/upload.html, ensure that only one avatar can be selected, and pets can upload multiple pictures

<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.thymeleaf.org">
<head>
    <meta charset="UTF-8">
    <title>upload</title>
</head>
<body bgcolor="#CED3FE">
<img  src="images/1.GIF"/ alt="How to implement SpringBoot file upload function" >
<hr/>
<div >
    <h2>注册用户~</h2>
    <form action="#" th:action="@{/upload}" method="post" enctype="multipart/form-data">
        用户名:<input type="text"  name="name"/><br/><br/>
        电　邮:<input type="text"  name="email"/><br/><br/>
        年　龄:<input type="text"  name="age"/><br/><br/>
        职　位:<input type="text"  name="job"/><br/><br/>
        头　像:<input type="file"  name="header"><br/><br/>
        宠　物:<input type="file"  name="photos" multiple><br/><br/>
        <input type="submit" value="注册"/>
        <input type="reset" value="重新填写"/>
    </form>
</div>
<hr/>
</body>
</html>

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2. Create src\main\java\com\llp\springboot\controller \UploadController.java

@Slf4j
@Controller
public class UploadController {
    //处理转发到用户注册-可以完成文件上传页面
    @GetMapping("/upload.html")
    public String uploadPage() {
        return "upload";// 视图解析,转发到templates/upload.html
    }
    @PostMapping("/upload")
    @ResponseBody
    public String upload(@RequestParam("name") String name,
                         @RequestParam("email") String email,
                         @RequestParam("age") Integer age,
                         @RequestParam("job") String job,
                         @RequestParam("header") MultipartFile header,
                         @RequestParam("photos") MultipartFile[] photos) throws IOException {
        log.info("name:{},email:{},age:{},job:{},header.size:{},photos.length:{}",name,email,age,job,header.getSize(),photos.length);
        //1.获取源文件名称
        String originalFilename = header.getOriginalFilename();
        // /E:/IdeaProjects/springboot-sysuser/target/classes/
        String path = ResourceUtils.getURL("classpath:").getPath();
        System.out.println(path);
        File file = new File(path+"static/images/upload/");
        if(!file.exists()){
            file.mkdirs();
        }
        header.transferTo(new File(path+"static/images/upload/"+originalFilename));
        return "注册用户成功/文件上传成功";
    }
}

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How to implement SpringBoot file upload function

##3. Lead to two questions

1. File overwriting problem

In the above example, file upload is implemented, but when two different files have the same file name, there will be a file overwriting problem. How to solve it?

@PostMapping("/upload")
@ResponseBody
public String upload(@RequestParam("name") String name,
                     @RequestParam("email") String email,
                     @RequestParam("age") Integer age,
                     @RequestParam("job") String job,
                     @RequestParam("header") MultipartFile header,
                     @RequestParam("photos") MultipartFile[] photos) throws IOException {
    log.info("name:{},email:{},age:{},job:{},header.size:{},photos.length:{}",name,email,age,job,header.getSize(),photos.length);
    //1.获取源文件名称
    String originalFilename = header.getOriginalFilename();
    originalFilename = UUID.randomUUID().toString().replaceAll("-","")+System.nanoTime()+originalFilename;
    //2.获取文件上传的路径
    // /E:/IdeaProjects/springboot-sysuser/target/classes/
    String path = ResourceUtils.getURL("classpath:").getPath();
    System.out.println(path);
    //3.动态的创建文件上传目录
    File file = new File(path+"static/images/upload/");
    if(!file.exists()){
        file.mkdirs();
    }
    //4.将文件传输到目标目录
    header.transferTo(new File(path+"static/images/upload/"+originalFilename));
    return "注册用户成功/文件上传成功";
}

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originalFilename = UUID.randomUUID().toString().replaceAll("-","") System.nanoTime() originalFilename;, the implementation idea is to re-upload the file Specify a unique file name

How to implement SpringBoot file upload function

2. Upload all files to one directory. When uploading a lot of files, accessing the files will slow down

Solution: Upload files to different directories. For example, files uploaded on one day should be put into one folder year/month/day, such as 2022/11/11 directory

public class WebUtils {
    //定义一个文件上传的路径
    public static String  UPLOAD_FILE_DIRECTORY = "static/images/upload/";
    //编写方法，生成一个目录-根据当前日期 年/月/日
    public static String getUploadFileDirectory() {
        return UPLOAD_FILE_DIRECTORY + new SimpleDateFormat("yyyy/MM/dd").format(new Date());
    }
}

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@PostMapping("/upload")
@ResponseBody
public String upload(@RequestParam("name") String name,
                     @RequestParam("email") String email,
                     @RequestParam("age") Integer age,
                     @RequestParam("job") String job,
                     @RequestParam("header") MultipartFile header,
                     @RequestParam("photos") MultipartFile[] photos) throws IOException {
    //输出获取到的信息
    log.info("上传的信息 name={} email={} age={} job={} header={} photos={} ",
            name, email, age, job, header.getSize(), photos.length);
    //得到类路径(运行的时候)
    String path = ResourceUtils.getURL("classpath:").getPath();
    //log.info("path={}", path);
    //动态创建指定目录
    File file = new File(path + WebUtils.getUploadFileDirectory());
    if (!file.exists()) {//如果目录不存在，我们就创建, 在java io
        file.mkdirs();
    }
    if (!header.isEmpty()) {//处理头像
        //获取上传文件的名字
        String originalFilename = header.getOriginalFilename();
        String fileName = UUID.randomUUID().toString() + "_" + System.currentTimeMillis() + "_" + originalFilename;
        //保存到动态创建的目录
        header.transferTo(new File(file.getAbsolutePath() + "/" + fileName));
    }
    //处理多个文件
    if (photos.length > 0) {
        for (MultipartFile photo : photos) {//遍历
            if (!photo.isEmpty()) {
                String originalFilename = photo.getOriginalFilename();
                String fileName = UUID.randomUUID().toString() + "_" + System.currentTimeMillis() + "_" + originalFilename;
                //保存到动态创建的目录
                photo.transferTo(new File(file.getAbsolutePath() + "/" + fileName));
            }
        }
    }
    return "注册用户成功/文件上传成功";
}

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How to implement SpringBoot file upload function

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