深海游弋的鱼 – 默默的点滴

在本文中，您将学习如何使用 Spring Boot 实现 Web 服务中的文件上传和下载功能。首先会构建一个 REST APIs 实现上传及下载的功能，然后使用 Postman 工具来测试这些接口，最后创建一个 Web 界面使用 JavaScript 调用接口演示完整的功能。最终界面及功能如下：

项目环境

- Spring Boot : 2.1.3.RELEASE
- Gredle : 5.2.1
- Java : 1.8
- Intellij IDEA : 2018.3.3

- Spring Boot : 2.1.3.RELEASE

- Gredle : 5.2.1

- Java : 1.8

- Intellij IDEA : 2018.3.3

项目创建

开发环境为 Intellij IDEA，项目创建很简单，按照下面的步骤创建即可：

File -> New -> Project...
选择 Spring Initializr，点击 Next
填写 Group (项目域名) 和 Artifact (项目别名)
构建类型可以选择 Maven 或 Gradle，看个人习惯
添加 Web 依赖
输入项目名称及保存路径，完成创建

项目创建完毕之后就可以进行开发，项目的完整结构如下图所示：

参数配置

项目创建完成之后，需要设置一些必要的参数，打开项目resources目录下配置文件application.properties，在其中添加以下参数：

server.port=80

## MULTIPART (MultipartProperties)
# 开启 multipart 上传功能
spring.servlet.multipart.enabled=true
# 文件写入磁盘的阈值
spring.servlet.multipart.file-size-threshold=2KB
# 最大文件大小
spring.servlet.multipart.max-file-size=200MB
# 最大请求大小
spring.servlet.multipart.max-request-size=215MB

## 文件存储所需参数
# 所有通过 REST APIs 上传的文件都将存储在此目录下
file.upload-dir=./uploads

server.port=80

## MULTIPART (MultipartProperties)

# 开启 multipart 上传功能

spring.servlet.multipart.enabled=true

# 文件写入磁盘的阈值

spring.servlet.multipart.file-size-threshold=2KB

# 最大文件大小

spring.servlet.multipart.max-file-size=200MB

# 最大请求大小

spring.servlet.multipart.max-request-size=215MB

## 文件存储所需参数

# 所有通过 REST APIs 上传的文件都将存储在此目录下

file.upload-dir=./uploads

其中file.upload-dir=./uploads参数为自定义的参数，创建FileProperties.javaPOJO类，使配置参数可以自动绑定到POJO类。

import org.springframework.boot.context.properties.ConfigurationProperties;

@ConfigurationProperties(prefix = "file")
public class FileProperties {

    private String uploadDir;

    public String getUploadDir() {
        return uploadDir;
    }

    public void setUploadDir(String uploadDir) {
        this.uploadDir = uploadDir;
    }
}

import org.springframework.boot.context.properties.ConfigurationProperties;

@ConfigurationProperties(prefix = "file")

public class FileProperties {

private String uploadDir;

public String getUploadDir() {

return uploadDir;

}

public void setUploadDir(String uploadDir) {

this.uploadDir = uploadDir;

}

然后在@SpringBootApplication注解的类中添加@EnableConfigurationProperties注解以开启ConfigurationProperties功能。

SpringBootFileApplication.java

@SpringBootApplication
@EnableConfigurationProperties({FileProperties.class})
public class SpringBootFileApplication {

    public static void main(String[] args) {
        SpringApplication.run(SpringBootFileApplication.class, args);
    }
}

@SpringBootApplication

@EnableConfigurationProperties({FileProperties.class})

public class SpringBootFileApplication {

public static void main(String[] args) {

SpringApplication.run(SpringBootFileApplication.class, args);

}

配置完成，以后若有file前缀开头的参数需要配置，可直接在application.properties配置文件中配置并更新FileProperties.java即可。

另外再创建一个上传文件成功之后的Response响应实体类UploadFileResponse.java及异常类FileException.java来处理异常信息。

UploadFileResponse.java

public class UploadFileResponse {
    private String fileName;
    private String fileDownloadUri;
    private String fileType;
    private long size;

    public UploadFileResponse(String fileName, String fileDownloadUri, String fileType, long size) {
        this.fileName = fileName;
        this.fileDownloadUri = fileDownloadUri;
        this.fileType = fileType;
        this.size = size;
    }
    // getter and setter ...
}

public class UploadFileResponse {

private String fileName;

private String fileDownloadUri;

private String fileType;

private long size;

public UploadFileResponse(String fileName, String fileDownloadUri, String fileType, long size) {

this.fileName = fileName;

this.fileDownloadUri = fileDownloadUri;

this.fileType = fileType;

this.size = size;

}

// getter and setter ...

}

FileException.java

public class FileException extends RuntimeException {

    public FileException(String message) {
        super(message);
    }

    public FileException(String message, Throwable cause) {
        super(message, cause);
    }
}

public class FileException extends RuntimeException {

public FileException(String message) {

super(message);

}

public FileException(String message, Throwable cause) {

super(message, cause);

}

创建接口

下面需要创建文件上传下载所需的 REST APIs 接口。创建文件FileController.java。

import com.james.sample.file.dto.UploadFileResponse;
import com.james.sample.file.service.FileService;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.core.io.Resource;
import org.springframework.http.HttpHeaders;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.*;
import org.springframework.web.multipart.MultipartFile;
import org.springframework.web.servlet.support.ServletUriComponentsBuilder;
import javax.servlet.http.HttpServletRequest;
import java.io.IOException;
import java.util.Arrays;
import java.util.List;
import java.util.stream.Collectors;

@RestController
public class FileController {

    private static final Logger logger = LoggerFactory.getLogger(FileController.class);

    @Autowired
    private FileService fileService;

    @PostMapping("/uploadFile")
    public UploadFileResponse uploadFile(@RequestParam("file") MultipartFile file){
        String fileName = fileService.storeFile(file);

        String fileDownloadUri = ServletUriComponentsBuilder.fromCurrentContextPath()
                .path("/downloadFile/")
                .path(fileName)
                .toUriString();

        return new UploadFileResponse(fileName, fileDownloadUri,
                file.getContentType(), file.getSize());
    }


    @PostMapping("/uploadMultipleFiles")
    public List<UploadFileResponse> uploadMultipleFiles(@RequestParam("files") MultipartFile[] files) {
        return Arrays.stream(files)
                .map(this::uploadFile)
                .collect(Collectors.toList());
    }

    @GetMapping("/downloadFile/{fileName:.+}")
    public ResponseEntity<Resource> downloadFile(@PathVariable String fileName, HttpServletRequest request) {
        // Load file as Resource
        Resource resource = fileService.loadFileAsResource(fileName);

        // Try to determine file's content type
        String contentType = null;
        try {
            contentType = request.getServletContext().getMimeType(resource.getFile().getAbsolutePath());
        } catch (IOException ex) {
            logger.info("Could not determine file type.");
        }

        // Fallback to the default content type if type could not be determined
        if(contentType == null) {
            contentType = "application/octet-stream";
        }

        return ResponseEntity.ok()
                .contentType(MediaType.parseMediaType(contentType))
                .header(HttpHeaders.CONTENT_DISPOSITION, "attachment; filename=\"" + resource.getFilename() + "\"")
                .body(resource);
    }
}

import com.james.sample.file.dto.UploadFileResponse;

import com.james.sample.file.service.FileService;

import org.slf4j.Logger;

import org.slf4j.LoggerFactory;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.core.io.Resource;

import org.springframework.http.HttpHeaders;

import org.springframework.http.MediaType;

import org.springframework.http.ResponseEntity;

import org.springframework.web.bind.annotation.*;

import org.springframework.web.multipart.MultipartFile;

import org.springframework.web.servlet.support.ServletUriComponentsBuilder;

import javax.servlet.http.HttpServletRequest;

import java.io.IOException;

import java.util.Arrays;

import java.util.List;

import java.util.stream.Collectors;

@RestController

public class FileController {

private static final Logger logger = LoggerFactory.getLogger(FileController.class);

@Autowired

private FileService fileService;

@PostMapping("/uploadFile")

public UploadFileResponse uploadFile(@RequestParam("file") MultipartFile file){

String fileName = fileService.storeFile(file);

String fileDownloadUri = ServletUriComponentsBuilder.fromCurrentContextPath()

.path("/downloadFile/")

.path(fileName)

.toUriString();

return new UploadFileResponse(fileName, fileDownloadUri,

file.getContentType(), file.getSize());

}

@PostMapping("/uploadMultipleFiles")

public List<UploadFileResponse> uploadMultipleFiles(@RequestParam("files") MultipartFile[] files) {

return Arrays.stream(files)

.map(this::uploadFile)

.collect(Collectors.toList());

}

@GetMapping("/downloadFile/{fileName:.+}")

public ResponseEntity<Resource> downloadFile(@PathVariable String fileName, HttpServletRequest request) {

// Load file as Resource

Resource resource = fileService.loadFileAsResource(fileName);

// Try to determine file's content type

String contentType = null;

try {

contentType = request.getServletContext().getMimeType(resource.getFile().getAbsolutePath());

} catch (IOException ex) {

logger.info("Could not determine file type.");

}

// Fallback to the default content type if type could not be determined

if(contentType == null) {

contentType = "application/octet-stream";

}

return ResponseEntity.ok()

.contentType(MediaType.parseMediaType(contentType))

.header(HttpHeaders.CONTENT_DISPOSITION, "attachment; filename=\"" + resource.getFilename() + "\"")

.body(resource);

}

FileController类在接收到用户的请求后，使用FileService类提供的storeFile()方法将文件写入到系统中进行存储，其存储目录就是之前在application.properties配置文件中的file.upload-dir参数的值./uploads。

下载接口downloadFile()在接收到用户请求之后，使用FileService类提供的loadFileAsResource()方法获取存储在系统中文件并返回文件供用户下载。

import com.james.sample.file.exception.FileException;
import com.james.sample.file.property.FileProperties;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.core.io.Resource;
import org.springframework.core.io.UrlResource;
import org.springframework.stereotype.Service;
import org.springframework.util.StringUtils;
import org.springframework.web.multipart.MultipartFile;
import java.io.IOException;
import java.net.MalformedURLException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.nio.file.StandardCopyOption;

@Service
public class FileService {

    private final Path fileStorageLocation; // 文件在本地存储的地址

    @Autowired
    public FileService(FileProperties fileProperties) {
        this.fileStorageLocation = Paths.get(fileProperties.getUploadDir()).toAbsolutePath().normalize();
        try {
            Files.createDirectories(this.fileStorageLocation);
        } catch (Exception ex) {
            throw new FileException("Could not create the directory where the uploaded files will be stored.", ex);
        }
    }

    /**
     * 存储文件到系统
     *
     * @param file 文件
     * @return 文件名
     */
    public String storeFile(MultipartFile file) {
        // Normalize file name
        String fileName = StringUtils.cleanPath(file.getOriginalFilename());

        try {
            // Check if the file's name contains invalid characters
            if(fileName.contains("..")) {
                throw new FileException("Sorry! Filename contains invalid path sequence " + fileName);
            }

            // Copy file to the target location (Replacing existing file with the same name)
            Path targetLocation = this.fileStorageLocation.resolve(fileName);
            Files.copy(file.getInputStream(), targetLocation, StandardCopyOption.REPLACE_EXISTING);

            return fileName;
        } catch (IOException ex) {
            throw new FileException("Could not store file " + fileName + ". Please try again!", ex);
        }
    }

    /**
     * 加载文件
     * @param fileName 文件名
     * @return 文件
     */
    public Resource loadFileAsResource(String fileName) {
        try {
            Path filePath = this.fileStorageLocation.resolve(fileName).normalize();
            Resource resource = new UrlResource(filePath.toUri());
            if(resource.exists()) {
                return resource;
            } else {
                throw new FileException("File not found " + fileName);
            }
        } catch (MalformedURLException ex) {
            throw new FileException("File not found " + fileName, ex);
        }
    }
}

import com.james.sample.file.exception.FileException;

import com.james.sample.file.property.FileProperties;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.core.io.Resource;

import org.springframework.core.io.UrlResource;

import org.springframework.stereotype.Service;

import org.springframework.util.StringUtils;

import org.springframework.web.multipart.MultipartFile;

import java.io.IOException;

import java.net.MalformedURLException;

import java.nio.file.Files;

import java.nio.file.Path;

import java.nio.file.Paths;

import java.nio.file.StandardCopyOption;

@Service

public class FileService {

private final Path fileStorageLocation; // 文件在本地存储的地址

@Autowired

public FileService(FileProperties fileProperties) {

this.fileStorageLocation = Paths.get(fileProperties.getUploadDir()).toAbsolutePath().normalize();

try {

Files.createDirectories(this.fileStorageLocation);

} catch (Exception ex) {

throw new FileException("Could not create the directory where the uploaded files will be stored.", ex);

}

/**

* 存储文件到系统

* @param file 文件

* @return 文件名

public String storeFile(MultipartFile file) {

// Normalize file name

String fileName = StringUtils.cleanPath(file.getOriginalFilename());

try {

// Check if the file's name contains invalid characters

if(fileName.contains("..")) {

throw new FileException("Sorry! Filename contains invalid path sequence " + fileName);

}

// Copy file to the target location (Replacing existing file with the same name)

Path targetLocation = this.fileStorageLocation.resolve(fileName);

Files.copy(file.getInputStream(), targetLocation, StandardCopyOption.REPLACE_EXISTING);

return fileName;

} catch (IOException ex) {

throw new FileException("Could not store file " + fileName + ". Please try again!", ex);

}

/**

* 加载文件

* @param fileName 文件名

* @return 文件

public Resource loadFileAsResource(String fileName) {

try {

Path filePath = this.fileStorageLocation.resolve(fileName).normalize();

Resource resource = new UrlResource(filePath.toUri());

if(resource.exists()) {

return resource;

} else {

throw new FileException("File not found " + fileName);

}

} catch (MalformedURLException ex) {

throw new FileException("File not found " + fileName, ex);

}

接口测试

在完成上述的代码之后，打开SpringBootFileApplication.java并运行，运行完成之后就可以使用 Postman 进行测试了。

单个文件上传结果：

多个文件上传结果：

文件下载结果：

Web 前端开发

<!DOCTYPE html>
<html lang="zh-cn">
<head>
    <!-- Required meta tags -->
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
    <title>Spring Boot File Upload / Download Rest API Example</title>

    <!-- Bootstrap CSS -->
    <link href="/css/main.css" rel="stylesheet"/>
</head>
<body>
<noscript>
    <h2>Sorry! Your browser doesn't support Javascript</h2>
</noscript>
<div class="upload-container">
    <div class="upload-header">
        <h2>Spring Boot File Upload / Download Rest API Example</h2>
    </div>
    <div class="upload-content">
        <div class="single-upload">
            <h3>Upload Single File</h3>
            <form id="singleUploadForm" name="singleUploadForm">
                <input id="singleFileUploadInput" type="file" name="file" class="file-input" required/>
                <button type="submit" class="primary submit-btn">Submit</button>
            </form>
            <div class="upload-response">
                <div id="singleFileUploadError"></div>
                <div id="singleFileUploadSuccess"></div>
            </div>
        </div>
        <div class="multiple-upload">
            <h3>Upload Multiple Files</h3>
            <form id="multipleUploadForm" name="multipleUploadForm">
                <input id="multipleFileUploadInput" type="file" name="files" class="file-input" multiple required/>
                <button type="submit" class="primary submit-btn">Submit</button>
            </form>
            <div class="upload-response">
                <div id="multipleFileUploadError"></div>
                <div id="multipleFileUploadSuccess"></div>
            </div>
        </div>
    </div>
</div>
<!-- Optional JavaScript -->
<script src="/js/main.js"></script>
</body>
</html>

<!DOCTYPE html>

<head>

<title>Spring Boot File Upload / Download Rest API Example</title>

</head>

<body>

<h2>Sorry! Your browser doesn't support Javascript</h2>

</noscript>

<h2>Spring Boot File Upload / Download Rest API Example</h2>

</div>

<h3>Upload Single File</h3>

<button type="submit" class="primary submit-btn">Submit</button>

</form>

</div>

<h3>Upload Multiple Files</h3>

<button type="submit" class="primary submit-btn">Submit</button>

</form>

</div>

</body>

</html>

* {
    -webkit-box-sizing: border-box;
    -moz-box-sizing: border-box;
    box-sizing: border-box;
}
body {
    margin: 0;
    padding: 0;
    font-weight: 400;
    font-family: "Helvetica Neue", Helvetica, Arial, sans-serif;
    font-size: 1rem;
    line-height: 1.58;
    color: #333;
    background-color: #f4f4f4;
}
body:before {
    height: 50%;
    width: 100%;
    position: absolute;
    top: 0;
    left: 0;
    background: #128ff2;
    content: "";
    z-index: 0;
}
.clearfix:after {
    display: block;
    content: "";
    clear: both;
}
h1, h2, h3, h4, h5, h6 {
    margin-top: 20px;
    margin-bottom: 20px;
}
h1 {
    font-size: 1.7em;
}
a {
    color: #128ff2;
}
button {
    box-shadow: none;
    border: 1px solid transparent;
    font-size: 14px;
    outline: none;
    line-height: 100%;
    white-space: nowrap;
    vertical-align: middle;
    padding: 0.6rem 1rem;
    border-radius: 2px;
    transition: all 0.2s ease-in-out;
    cursor: pointer;
    min-height: 38px;
}
button.primary {
    background-color: #128ff2;
    box-shadow: 0 2px 2px 0 rgba(0, 0, 0, 0.12);
    color: #fff;
}
input {
    font-size: 1rem;
}
input[type="file"] {
    border: 1px solid #128ff2;
    padding: 6px;
    max-width: 100%;
}
.file-input {
    width: 100%;
}
.submit-btn {
    display: block;
    margin-top: 15px;
    min-width: 100px;
}
@media screen and (min-width: 500px) {
    .file-input {
        width: calc(100% - 115px);
    }

    .submit-btn {
        display: inline-block;
        margin-top: 0;
        margin-left: 10px;
    }
}
.upload-container {
    max-width: 700px;
    margin-left: auto;
    margin-right: auto;
    background-color: #fff;
    box-shadow: 0 1px 11px rgba(0, 0, 0, 0.27);
    margin-top: 60px;
    min-height: 400px;
    position: relative;
    padding: 20px;
}
.upload-header {
    border-bottom: 1px solid #ececec;
}
.upload-header h2 {
    font-weight: 500;
}
.single-upload {
    padding-bottom: 20px;
    margin-bottom: 20px;
    border-bottom: 1px solid #e8e8e8;
}
.upload-response {
    overflow-x: hidden;
    word-break: break-all;
}

100

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* {

-webkit-box-sizing: border-box;

-moz-box-sizing: border-box;

box-sizing: border-box;

}

body {

margin: 0;

padding: 0;

font-weight: 400;

font-family: "Helvetica Neue", Helvetica, Arial, sans-serif;

font-size: 1rem;

line-height: 1.58;

color: #333;

background-color: #f4f4f4;

}

body:before {

height: 50%;

width: 100%;

position: absolute;

top: 0;

left: 0;

background: #128ff2;

content: "";

z-index: 0;

}

.clearfix:after {

display: block;

content: "";

clear: both;

}

h1, h2, h3, h4, h5, h6 {

margin-top: 20px;

margin-bottom: 20px;

}

h1 {

font-size: 1.7em;

}

a {

color: #128ff2;

}

button {

box-shadow: none;

border: 1px solid transparent;

font-size: 14px;

outline: none;

line-height: 100%;

white-space: nowrap;

vertical-align: middle;

padding: 0.6rem 1rem;

border-radius: 2px;

transition: all 0.2s ease-in-out;

cursor: pointer;

min-height: 38px;

}

button.primary {

background-color: #128ff2;

box-shadow: 0 2px 2px 0 rgba(0, 0, 0, 0.12);

color: #fff;

}

input {

font-size: 1rem;

}

input[type="file"] {

border: 1px solid #128ff2;

padding: 6px;

max-width: 100%;

}

.file-input {

width: 100%;

}

.submit-btn {

display: block;

margin-top: 15px;

min-width: 100px;

}

@media screen and (min-width: 500px) {

.file-input {

width: calc(100% - 115px);

}

.submit-btn {

display: inline-block;

margin-top: 0;

margin-left: 10px;

}

.upload-container {

max-width: 700px;

margin-left: auto;

margin-right: auto;

background-color: #fff;

box-shadow: 0 1px 11px rgba(0, 0, 0, 0.27);

margin-top: 60px;

min-height: 400px;

position: relative;

padding: 20px;

}

.upload-header {

border-bottom: 1px solid #ececec;

}

.upload-header h2 {

font-weight: 500;

}

.single-upload {

padding-bottom: 20px;

margin-bottom: 20px;

border-bottom: 1px solid #e8e8e8;

}

.upload-response {

overflow-x: hidden;

word-break: break-all;

}

'use strict';

var singleUploadForm = document.querySelector('#singleUploadForm');
var singleFileUploadInput = document.querySelector('#singleFileUploadInput');
var singleFileUploadError = document.querySelector('#singleFileUploadError');
var singleFileUploadSuccess = document.querySelector('#singleFileUploadSuccess');

var multipleUploadForm = document.querySelector('#multipleUploadForm');
var multipleFileUploadInput = document.querySelector('#multipleFileUploadInput');
var multipleFileUploadError = document.querySelector('#multipleFileUploadError');
var multipleFileUploadSuccess = document.querySelector('#multipleFileUploadSuccess');

function uploadSingleFile(file) {
    var formData = new FormData();
    formData.append("file", file);

    var xhr = new XMLHttpRequest();
    xhr.open("POST", "/uploadFile");

    xhr.onload = function() {
        console.log(xhr.responseText);
        var response = JSON.parse(xhr.responseText);
        if(xhr.status == 200) {
            singleFileUploadError.style.display = "none";
            singleFileUploadSuccess.innerHTML = "<p>File Uploaded Successfully.</p><p>DownloadUrl : <a href='" + response.fileDownloadUri + "' target='_blank'>" + response.fileDownloadUri + "</a></p>";
            singleFileUploadSuccess.style.display = "block";
        } else {
            singleFileUploadSuccess.style.display = "none";
            singleFileUploadError.innerHTML = (response && response.message) || "Some Error Occurred";
        }
    }

    xhr.send(formData);
}

function uploadMultipleFiles(files) {
    var formData = new FormData();
    for(var index = 0; index < files.length; index++) {
        formData.append("files", files[index]);
    }

    var xhr = new XMLHttpRequest();
    xhr.open("POST", "/uploadMultipleFiles");

    xhr.onload = function() {
        console.log(xhr.responseText);
        var response = JSON.parse(xhr.responseText);
        if(xhr.status == 200) {
            multipleFileUploadError.style.display = "none";
            var content = "<p>All Files Uploaded Successfully</p>";
            for(var i = 0; i < response.length; i++) {
                content += "<p>DownloadUrl : <a href='" + response[i].fileDownloadUri + "' target='_blank'>" + response[i].fileDownloadUri + "</a></p>";
            }
            multipleFileUploadSuccess.innerHTML = content;
            multipleFileUploadSuccess.style.display = "block";
        } else {
            multipleFileUploadSuccess.style.display = "none";
            multipleFileUploadError.innerHTML = (response && response.message) || "Some Error Occurred";
        }
    }

    xhr.send(formData);
}

singleUploadForm.addEventListener('submit', function(event){
    var files = singleFileUploadInput.files;
    if(files.length === 0) {
        singleFileUploadError.innerHTML = "Please select a file";
        singleFileUploadError.style.display = "block";
    }
    uploadSingleFile(files[0]);
    event.preventDefault();
}, true);

multipleUploadForm.addEventListener('submit', function(event){
    var files = multipleFileUploadInput.files;
    if(files.length === 0) {
        multipleFileUploadError.innerHTML = "Please select at least one file";
        multipleFileUploadError.style.display = "block";
    }
    uploadMultipleFiles(files);
    event.preventDefault();
}, true);

'use strict';

var singleUploadForm = document.querySelector('#singleUploadForm');

var singleFileUploadInput = document.querySelector('#singleFileUploadInput');

var singleFileUploadError = document.querySelector('#singleFileUploadError');

var singleFileUploadSuccess = document.querySelector('#singleFileUploadSuccess');

var multipleUploadForm = document.querySelector('#multipleUploadForm');

var multipleFileUploadInput = document.querySelector('#multipleFileUploadInput');

var multipleFileUploadError = document.querySelector('#multipleFileUploadError');

var multipleFileUploadSuccess = document.querySelector('#multipleFileUploadSuccess');

function uploadSingleFile(file) {

var formData = new FormData();

formData.append("file", file);

var xhr = new XMLHttpRequest();

xhr.open("POST", "/uploadFile");

xhr.onload = function() {

console.log(xhr.responseText);

var response = JSON.parse(xhr.responseText);

if(xhr.status == 200) {

singleFileUploadError.style.display = "none";

singleFileUploadSuccess.innerHTML = "<p>File Uploaded Successfully.</p><p>DownloadUrl : <a href='" + response.fileDownloadUri + "' target='_blank'>" + response.fileDownloadUri + "</a></p>";

singleFileUploadSuccess.style.display = "block";

} else {

singleFileUploadSuccess.style.display = "none";

singleFileUploadError.innerHTML = (response && response.message) || "Some Error Occurred";

}

xhr.send(formData);

}

function uploadMultipleFiles(files) {

var formData = new FormData();

for(var index = 0; index < files.length; index++) {

formData.append("files", files[index]);

}

var xhr = new XMLHttpRequest();

xhr.open("POST", "/uploadMultipleFiles");

xhr.onload = function() {

console.log(xhr.responseText);

var response = JSON.parse(xhr.responseText);

if(xhr.status == 200) {

multipleFileUploadError.style.display = "none";

var content = "<p>All Files Uploaded Successfully</p>";

for(var i = 0; i < response.length; i++) {

content += "<p>DownloadUrl : <a href='" + response[i].fileDownloadUri + "' target='_blank'>" + response[i].fileDownloadUri + "</a></p>";

}

multipleFileUploadSuccess.innerHTML = content;

multipleFileUploadSuccess.style.display = "block";

} else {

multipleFileUploadSuccess.style.display = "none";

multipleFileUploadError.innerHTML = (response && response.message) || "Some Error Occurred";

}

xhr.send(formData);

}

singleUploadForm.addEventListener('submit', function(event){

var files = singleFileUploadInput.files;

if(files.length === 0) {

singleFileUploadError.innerHTML = "Please select a file";

singleFileUploadError.style.display = "block";

}

uploadSingleFile(files[0]);

event.preventDefault();

}, true);

multipleUploadForm.addEventListener('submit', function(event){

var files = multipleFileUploadInput.files;

if(files.length === 0) {

multipleFileUploadError.innerHTML = "Please select at least one file";

multipleFileUploadError.style.display = "block";

}

uploadMultipleFiles(files);

event.preventDefault();

}, true);

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用SpringBoot框架来接收multipart/form-data文件

项目环境

项目创建

参数配置

创建接口

接口测试

Web 前端开发

参考链接

发布者

默默

发表回复取消回复

项目环境

项目创建

参数配置

创建接口

接口测试

Web 前端开发

参考链接

发布者

默默

发表回复 取消回复

发表回复取消回复