SpringBoot文件上传下载

项目中经常会有上传和下载的需求，这篇文章简述一下springboot项目中实现简单的上传和下载。

新建springboot项目，前台页面使用的thymeleaf模板，其余的没有特别的配置，pom代码如下：

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.dalaoyang</groupId>
    <artifactId>springboot_upload_download</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>springboot_upload_download</name>
    <description>springboot_upload_download</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.9.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-thymeleaf</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>

        <dependency>
            <groupId>net.sourceforge.nekohtml</groupId>
            <artifactId>nekohtml</artifactId>
            <version>1.9.15</version>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>


</project>

前台页面index.html，其中包含单个上传，下载，批量上传。

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<p>单文件上传</p>
<form action="upload" method="POST" enctype="multipart/form-data">
    文件：<input type="file" name="file"/>
    <input type="submit"/>
</form>
<hr/>
<p>文件下载</p>
<a href="download">下载文件</a>
<hr/>
<p>多文件上传</p>
<form method="POST" enctype="multipart/form-data" action="batch">
    <p>文件1：<input type="file" name="file"/></p>
    <p>文件2：<input type="file" name="file"/></p>
    <p><input type="submit" value="上传"/></p>
</form>
</body>
</html>

IndexController只是用来页面的跳转

package com.dalaoyang.Controller;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;

/**
 * @author dalaoyang
 * @Description
 * @project springboot_learn
 * @package com.dalaoyang.Controller
 * @email yangyang@dalaoyang.cn
 * @date 2018/4/9
 */
@Controller
public class IndexController {

    @RequestMapping("/")
    public String index()
    {
        return "index";
    }
}

最后是本文的重点，FileController，其中包含单个上传，单个下载，批量上传对应的方法。需要注意下载功能写的是对应我电脑里面固定位置的文件，仅供大家来参考。以下是代码：

package com.dalaoyang.Controller;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.web.bind.annotation.*;
import org.springframework.web.multipart.MultipartFile;
import org.springframework.web.multipart.MultipartHttpServletRequest;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.*;
import java.util.List;


/**
 * @author dalaoyang
 * @Description
 * @project springboot_learn
 * @package com.dalaoyang.Controller
 * @email yangyang@dalaoyang.cn
 * @date 2018/4/9
 */
@RestController
public class FileController {
    private static final Logger log = LoggerFactory.getLogger(FileController.class);

    @RequestMapping(value = "/upload")
    public String upload(@RequestParam("file") MultipartFile file) {
        try {
            if (file.isEmpty()) {
                return "文件为空";
            }
            // 获取文件名
            String fileName = file.getOriginalFilename();
            log.info("上传的文件名为：" + fileName);
            // 获取文件的后缀名
            String suffixName = fileName.substring(fileName.lastIndexOf("."));
            log.info("文件的后缀名为：" + suffixName);
            // 设置文件存储路径
            String filePath = "/Users/dalaoyang/Downloads/";
            String path = filePath + fileName;
            File dest = new File(path);
            // 检测是否存在目录
            if (!dest.getParentFile().exists()) {
                dest.getParentFile().mkdirs();// 新建文件夹
            }
            file.transferTo(dest);// 文件写入
            return "上传成功";
        } catch (IllegalStateException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return "上传失败";
    }

    @PostMapping("/batch")
    public String handleFileUpload(HttpServletRequest request) {
        List<MultipartFile> files = ((MultipartHttpServletRequest) request).getFiles("file");
        MultipartFile file = null;
        BufferedOutputStream stream = null;
        for (int i = 0; i < files.size(); ++i) {
            file = files.get(i);
            String filePath = "/Users/dalaoyang/Downloads/";
            if (!file.isEmpty()) {
                try {
                    byte[] bytes = file.getBytes();
                    stream = new BufferedOutputStream(new FileOutputStream(
                            new File(filePath + file.getOriginalFilename())));//设置文件路径及名字
                    stream.write(bytes);// 写入
                    stream.close();
                } catch (Exception e) {
                    stream = null;
                    return "第 " + i + " 个文件上传失败 ==> "
                            + e.getMessage();
                }
            } else {
                return "第 " + i
                        + " 个文件上传失败因为文件为空";
            }
        }
        return "上传成功";
    }

    @GetMapping("/download")
    public String downloadFile(HttpServletRequest request, HttpServletResponse response) {
        String fileName = "dalaoyang.jpeg";// 文件名
        if (fileName != null) {
            //设置文件路径
            File file = new File("/Users/dalaoyang/Documents/dalaoyang.jpeg");
            //File file = new File(realPath , fileName);
            if (file.exists()) {
                response.setContentType("application/force-download");// 设置强制下载不打开
                response.addHeader("Content-Disposition", "attachment;fileName=" + fileName);// 设置文件名
                byte[] buffer = new byte[1024];
                FileInputStream fis = null;
                BufferedInputStream bis = null;
                try {
                    fis = new FileInputStream(file);
                    bis = new BufferedInputStream(fis);
                    OutputStream os = response.getOutputStream();
                    int i = bis.read(buffer);
                    while (i != -1) {
                        os.write(buffer, 0, i);
                        i = bis.read(buffer);
                    }
                    return "下载成功";
                } catch (Exception e) {
                    e.printStackTrace();
                } finally {
                    if (bis != null) {
                        try {
                            bis.close();
                        } catch (IOException e) {
                            e.printStackTrace();
                        }
                    }
                    if (fis != null) {
                        try {
                            fis.close();
                        } catch (IOException e) {
                            e.printStackTrace();
                        }
                    }
                }
            }
        }
        return "下载失败";
    }
}

源码下载：大老杨码云

SpringBoot文件上传下载

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