文件上传和下载
pom.xml
<?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.atguigu</groupId>
<artifactId>spring_mvc_04_ajax</artifactId>
<version>1.0-SNAPSHOT</version>
<packaging>war</packaging>
<dependencies>
<!-- SpringMVC -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
<version>5.3.1</version>
</dependency>
<!-- 日志 -->
<dependency>
<groupId>ch.qos.logback</groupId>
<artifactId>logback-classic</artifactId>
<version>1.2.3</version>
</dependency>
<!-- ServletAPI -->
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>javax.servlet-api</artifactId>
<version>3.1.0</version>
<scope>provided</scope>
</dependency>
<!-- Spring5和Thymeleaf整合包 -->
<dependency>
<groupId>org.thymeleaf</groupId>
<artifactId>thymeleaf-Spring5</artifactId>
<version>3.0.12.RELEASE</version>
</dependency>
<!--导入jackson依赖-->
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
<version>2.12.4</version>
</dependency>
<!--文件上传需要-->
<dependency>
<groupId>commons-fileupload</groupId>
<artifactId>commons-fileupload</artifactId>
<version>1.3.1</version>
</dependency>
</dependencies>
</project>
web.xml
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
version="4.0">
<!--字符编码过滤器-->
<filter>
<filter-name>CharacterEncodingFilter</filter-name>
<filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
<init-param>
<param-name>encoding</param-name>
<param-value>UTF-8</param-value>
</init-param>
<init-param>
<param-name>forceEncoding</param-name>
<param-value>true</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>CharacterEncodingFilter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
<!--请求方法过滤器-->
<filter>
<filter-name>HiddenHttpMethodFilter</filter-name>
<filter-class>org.springframework.web.filter.HiddenHttpMethodFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>HiddenHttpMethodFilter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
<!--前端控制器-->
<servlet>
<servlet-name>SpringMVC</servlet-name>
<servlet-class>org.springframework.web.servlet.dispatcherServlet</servlet-class>
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:springmvc.xml</param-value>
</init-param>
<!--将前端控制器的初始化时间提前到服务器启动时-->
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>SpringMVC</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping>
</web-app>
index.html
<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.w3.org/1999/xhtml">
<head>
<Meta charset="UTF-8">
<title>首页</title>
</head>
<body>
<a th:href="@{/test/down}">下载图片</a><br>
<!--enctype="multipart/form-data":表示使用二进制的方式传输当前的数据-->
<form th:action="@{/test/up}" method="post" enctype="multipart/form-data">
头像:<input type="file" name="photo"><br/>
<input type="submit" value="上传">
</form>
</webody>
</html>
/**
* ResponseEntity:可以作为控制器方法的返回值,表示响应到浏览器的完整的响应报文
*
* 文件上传的的要求:
* 1.form表单的请求方式必须为post
* 2.form表单必须设置为enctype="multipart/form-data"
*/
@Controller
public class FileUpAndDownController {
@RequestMapping("/test/up")
public String testUp(multipartfile photo, HttpSession session) throws IOException {
//需要在springmvc配置文件中配置一个文件上传解析器
//获取上传的文件的文件名
String filename = photo.getoriginalFilename();
//解决文件重名问题
//获取上传文件的后缀
String hzName = filename.substring(filename.lastIndexOf("."));
//获取uuid
String uuid = UUID.randomUUID().toString();
//拼接一个新的文件名
filename = uuid+hzName;
//获取ServletContext对象
ServletContext servletContext = session.getServletContext();
//获取当前工程下photo目录的真实路径
String photoPath = servletContext.getRealPath("photo");
//创建photoPath所对应的File对象
File file = new File(photoPath);
//判断file所对应目录是否存在
if (!file.exists()){
file.mkdir();
}
String finalPath = photoPath+File.separator+filename;
//上传文件
photo.transferTo(new File(finalPath));
return "success";
}
@RequestMapping("/test/down")
public ResponseEntity<byte[]> testResponseEntity(HttpSession session) throws IOException {
//获取ServletContext对象
ServletContext servletContext = session.getServletContext();
//获取服务器中文件的真实路径
String realPath = servletContext.getRealPath("/img/a.png");
//创建输入流
FileInputStream is = new FileInputStream(realPath);
//创建字节数组, is.available()获取输入流所对应文件的字节数
byte[] bytes = new byte[is.available()];
//将流读到字节数组中
is.read(bytes);
//创建HttpHeaders对象设置响应头信息
MultiValueMap<String,String> headers = new HttpHeaders();
//设置要下载方式以及下载文件的名字
headers.add("Content-disposition","attachment;filename=1.jpg");
//设置响应状态码
HttpStatus statusCode = HttpStatus.OK;
//创建ResponseEntity对象
ResponseEntity<byte[]> responseEntity = new ResponseEntity<>(bytes, headers, statusCode);
//关闭输入流
is.close();
return responseEntity;
}
}