SpringBoot文件上传下载和多文件上传（图文详解）

最近在学习SpringBoot，以下是最近学习整理的实现文件上传下载的java代码：

1、开发环境：

IDEA15+ Maven+JDK1.8

2、新建一个maven工程：



3、工程框架



4、pom.xml文件依赖项

<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/maven-v4_0_0.xsd"> <modelVersion>4.0.0</modelVersion>
<groupId>SpringWebContent</groupId>
<artifactId>SpringWebContent</artifactId>
<packaging>war</packaging>
<version>1.0-SNAPSHOT</version>
<name>SpringWebContent Maven Webapp</name>
<url>http://maven.apache.org</url>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.4.3.RELEASE</version>
</parent>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-thymeleaf</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-devtools</artifactId>
<optional>true</optional>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>3.8.1</version>
<scope>test</scope>
</dependency>
</dependencies>
<properties>
<java.version>1.8</java.version>
</properties>
<build>
<finalName>SpringWebContent</finalName>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>

5、Application.java

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplication
public class Application {

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

6、FileController.java

import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RequestParam;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.web.bind.annotation.ResponseBody;
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;

@Controller
public class FileController {
@RequestMapping("/greeting")
public String greeting(@RequestParam(value="name", required=false, defaultValue="World") String name, Model model) {
model.addAttribute("name", name);
return "greeting";
}
private static final Logger logger = LoggerFactory.getLogger(FileController.class);
//文件上传相关代码
@RequestMapping(value = "upload")
@ResponseBody
public String upload(@RequestParam("test") MultipartFile file) {
if (file.isEmpty()) {
return "文件为空";
}
// 获取文件名
String fileName = file.getOriginalFilename();
logger.info("上传的文件名为：" + fileName);
// 获取文件的后缀名
String suffixName = fileName.substring(fileName.lastIndexOf("."));
logger.info("上传的后缀名为：" + suffixName);
// 文件上传后的路径
String filePath = "E://test//";
// 解决中文问题，liunx下中文路径，图片显示问题
// fileName = UUID.randomUUID() + suffixName;
File dest = new File(filePath + fileName);
// 检测是否存在目录
if (!dest.getParentFile().exists()) {
dest.getParentFile().mkdirs();
}
try {
file.transferTo(dest);
return "上传成功";
} catch (IllegalStateException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return "上传失败";
}

//文件下载相关代码
@RequestMapping("/download")
public String downloadFile(org.apache.catalina.servlet4preview.http.HttpServletRequest request, HttpServletResponse response){
String fileName = "FileUploadTests.java";
if (fileName != null) {
//当前是从该工程的WEB-INF//File//下获取文件(该目录可以在下面一行代码配置)然后下载到C:\\users\\downloads即本机的默认下载的目录
String realPath = request.getServletContext().getRealPath(
"//WEB-INF//");
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);
}
System.out.println("success");
} 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 null;
}
//多文件上传
@RequestMapping(value = "/batch/upload", method = RequestMethod.POST)
@ResponseBody
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);
if (!file.isEmpty()) {
try {
byte[] bytes = file.getBytes();
stream = new BufferedOutputStream(new FileOutputStream(
new File(file.getOriginalFilename())));
stream.write(bytes);
stream.close();

} catch (Exception e) {
stream = null;
return "You failed to upload " + i + " => "
+ e.getMessage();
}
} else {
return "You failed to upload " + i
+ " because the file was empty.";
}
}
return "upload successful";
}

7、index.html

<!DOCTYPE html>
<html lang="en">
<head>
<title>Getting Started: Serving Web Content</title>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
</head>
<body>
<p>Get your greeting <a href="/greeting">here</a></p>
<form action="/upload" method="POST" enctype="multipart/form-data">
文件：<input type="file" name="test"/>
<input type="submit" />
</form>
<a href="/download">下载test</a>
<p>多文件上传</p>
<form method="POST" enctype="multipart/form-data" action="/batch/upload">
<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>
</html>

本文代码参考Spring官网：https://spring.io/guides/gs/serving-web-content/

完整工程地址：http://download.csdn.net/detail/coding13/9739116

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