工程目录结构
完整代码：
1、pom.xml
首先当然是添加依赖，用到thymeleaf模板渲染html页面
<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.hello</groupId> <artifactId>HelloBoot</artifactId> <version>0.0.1-SNAPSHOT</version> <packaging>jar</packaging> <properties> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> </properties> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>2.0.1.BUILD-SNAPSHOT</version> </parent> <dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-thymeleaf</artifactId> </dependency> </dependencies> <repositories> <repository> <id>spring-snapshots</id> <name>Spring Snapshots</name> <url>https://repo.spring.io/libs-snapshot</url> <snapshots> <enabled>true</enabled> </snapshots> </repository> </repositories> </project>
如果遇到<parent>标签报错，看看和上面写的有出入吗---
2、application.properties
只有一行，关闭thymeleaf缓存
spring.thymeleaf.cache=false
3、file.html 页面
<!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml" xmlns:th="http://www.thymeleaf.org" xmlns:sec="http://www.thymeleaf.org/thymeleaf-extras-springsecurity3"> <head> <meta charset="UTF-8"> <title>Insert title here</title> </head> <body> <h1 th:inlines="text">文件上传</h1> <form action="fileUpload" method="post" enctype="multipart/form-data"> <p><input type="file" name="filename" /></p> <p><input type="submit" value="提交" /></p> </form> <a href="http://localhost:8080/fileDownload">下载</a> </body> </html>
4、HelloController.java 控制类
package com.hello; import java.io.BufferedInputStream; import java.io.File; import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.IOException; import java.io.OutputStream; import javax.servlet.http.HttpServletResponse; import org.springframework.stereotype.Controller; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RequestParam; import org.springframework.web.bind.annotation.ResponseBody; import org.springframework.web.multipart.MultipartFile; @Controller public class HelloController { //映射视图 @RequestMapping("/file") public String file() { return "/file"; } //上传 @RequestMapping("fileUpload") @ResponseBody public String fileUpload(@RequestParam("filename") MultipartFile file) { if(file.isEmpty()) { return "false"; } //将里面内容移动到目标文本文档 File dest = new File("D:/test.txt"); try { file.transferTo(dest); } catch (IllegalStateException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } return "success"; } //下载 @RequestMapping("fileDownload") @ResponseBody public String fileDownload(HttpServletResponse res) { String fileName = "1.jpg"; res.setHeader("content-type", "application/octet-stream"); res.setContentType("application/octet-stream"); res.setHeader("Content-Disposition", "attachment;filename=" + fileName); byte[] buff = new byte[1024]; BufferedInputStream bis = null; OutputStream os = null; try { os = res.getOutputStream(); //获取zhi'ding bis = new BufferedInputStream( new FileInputStream(new File("D:/1.jpg"))); int i = bis.read(buff); while(i != -1) { //每次读取1024字节，就flush输出 os.write(buff, 0, buff.length); os.flush(); //然后继续读取下一个1024字节 i = bis.read(buff); } } catch (FileNotFoundException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } finally { if (bis != null) { try { bis.close(); } catch (IOException e) { e.printStackTrace(); } } } return "success"; } }
（1）file()方法return返回的是视图“file.html”，使用@Controller修饰类即可
（2）上传业务方法fileUpload()，return返回的是个字符串——“false“或”success”，不是html视图页面，所以不用渲染视图，
这里使用@Controller修饰类 和 @ResponseBody修饰方法
5、启动类App.java
package com.hello; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; @SpringBootApplication public class App { public static void main(String[] args) { SpringApplication.run(App.class, args); } }