详解SpringBoot文件上传下载和多文件上传（图文）

<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>

import org.springframework.boot.SpringApplication;import org.springframework.boot.autoconfigure.SpringBootApplication;@SpringBootApplicationpublic class Application {  public static void main(String[] args) {    SpringApplication.run(Application.class, args);  }}

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;@Controllerpublic 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";  }

<!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" rel="external nofollow" >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" rel="external nofollow" >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>