SpringBoot 上传、下载（四）

时间：2023-03-10 01:46:06
SpringBoot 上传、下载（四）

工程目录结构

SpringBoot 上传、下载（四）

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.</modelVersion>

  <groupId>com.hello</groupId>

  <artifactId>HelloBoot</artifactId>

  <version>0.0.-SNAPSHOT</version>

  <packaging>jar</packaging>

  <properties>

    <project.build.sourceEncoding>UTF-</project.build.sourceEncoding>

  </properties>

  <parent>

    <groupId>org.springframework.boot</groupId>

    <artifactId>spring-boot-starter-parent</artifactId>

    <version>2.0..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[];

        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 != -) {

                //每次读取1024字节，就flush输出

                os.write(buff, , 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);

    }

}

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