自定义文件下载

Posted on 2021-07-14 11:31 嘿！！！！阅读(72) 评论(0) 编辑收藏举报

突然有个需求，需要从数据库获取数据，并生成文件下载。（很久没写都忘了，记录下）

1、我的伪代码是springboot+springmvc做的，项目结构：

1.1、项目依赖

 1 <?xml version="1.0" encoding="UTF-8"?>
 2 <project xmlns="http://maven.apache.org/POM/4.0.0"
 3          xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 4          xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
 5     <modelVersion>4.0.0</modelVersion>
 6     <!--SpringBoot的起步依赖spring-boot-starter-parent-->
 7     <parent>
 8         <groupId>org.springframework.boot</groupId>
 9         <artifactId>spring-boot-starter-parent</artifactId>
10         <version>2.0.1.RELEASE</version>
11     </parent>
12     <groupId>com.springbootdemo</groupId>
13     <artifactId>springbootdemo</artifactId>
14     <version>1.0-SNAPSHOT</version>
15     <dependencies>
16         <!--web的启动依赖-->
17         <dependency>
18             <groupId>org.springframework.boot</groupId>
19             <artifactId>spring-boot-starter-web</artifactId>
20         </dependency>
21         <dependency>
22             <groupId>commons-io</groupId>
23             <artifactId>commons-io</artifactId>
24             <version>2.6</version>
25         </dependency>
26         <dependency>
27             <groupId>cn.hutool</groupId>
28             <artifactId>hutool-core</artifactId>
29             <version>5.3.3</version>
30         </dependency>
31     </dependencies>
33 </project>

1.2、启动类

 1 package com.springboot.demo;
 2 
 3 import org.springframework.boot.SpringApplication;
 4 import org.springframework.boot.autoconfigure.SpringBootApplication;
 5 
 6 /**
 7  * @author dingpl
 8  * @date 2021/7/13 10:22
 9  */
10 @SpringBootApplication
11 public class MySpringBootApplication {
12     public static void main(String[] args) {
13         SpringApplication.run(MySpringBootApplication.class);
14     }
15 }

1.3、默认访问index.html

 1 package com.springboot.demo.controller;
 2 
 3 import org.springframework.context.annotation.Configuration;
 4 import org.springframework.core.Ordered;
 5 import org.springframework.web.servlet.config.annotation.ViewControllerRegistry;
 6 import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;
 7 
 8 /**
 9  * @author dingpl
10  * @date 2021/7/13 10:24
11  */
12 @Configuration
13 public class DemoController extends WebMvcConfigurerAdapter {
14     @Override
15     public void addViewControllers( ViewControllerRegistry registry ) {
16         registry.addViewController( "/" ).setViewName( "forward:/index.html" );
17         registry.setOrder( Ordered.HIGHEST_PRECEDENCE );
18         super.addViewControllers( registry );
19     }
20 }

1.4、index页面

<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.thymeleaf.org">
<head>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta name="renderer" content="webkit">
    <meta http-equiv="Cache-Control" content="no-siteapp"/>
    <title th:text="${titleName}">首页</title>
</head>

<body class="fixed-sidebar full-height-layout gray-bg"
      style="overflow: hidden">
<a id="download"  href="/file/download" >
    <i class="fa fa-download"></i>下载test文件</a>
</body>
</html>

1.5、项目启动效果

1.6、这是我优化之后的文件下载controller

 1 package com.springboot.demo.controller;
 2 import com.springboot.demo.utils.PathUtils;
 3 import org.springframework.stereotype.Controller;
 4 import org.springframework.web.bind.annotation.RequestMapping;
 5 import org.springframework.web.bind.annotation.RequestMethod;
 6 import org.xml.sax.SAXException;
 7 import org.apache.commons.io.FileUtils;
 8 import java.io.*;
 9 import javax.servlet.http.HttpServletResponse;
10 /**
11  * @author dingpl
12  * @date 2021/7/13 10:24
13  */
14 @Controller
15 @RequestMapping("file")
16 public class FileController{
17 
18     @RequestMapping(value = "download",method = RequestMethod.GET)
19     public void download(HttpServletResponse response) throws SAXException {
20         String content = "null";
21         String title = "test.xml";
22         File xmlFile = null;
23         Writer out = null;
24         try {
25             File dic = new File(PathUtils.getRootPath() + "/file/tmpfile");
26             if (!dic.exists()) {
27                 dic.mkdirs();
28             }
29             // 创建文件
30             xmlFile = new File(PathUtils.getRootPath() + "/file/tmpfile/"+title);
31             if (!xmlFile.exists()) {
32                 xmlFile.createNewFile();
33             }
34             //写入文件内容
35             out = new FileWriter(xmlFile);
36             out.write(content);
37             out.flush();
38             out.close();
39             response.reset();
40             response.setContentType("application/octet-stream");
41             //3.设置content-disposition响应头控制浏览器以下载的形式打开文件
42             response.setHeader("content-disposition", "attachment;filename=" + java.net.URLEncoder.encode(title, "UTF-8"));
43             // 输出文件
44             byte[] bytes = FileUtils.readFileToByteArray(xmlFile);
45             OutputStream outputStream = response.getOutputStream();
46             outputStream.write(bytes);//将缓冲区的数据输出到客户端浏览器
47         } catch (Exception e) {
48             e.printStackTrace();
49         } finally {
50             if (xmlFile.exists()) {
51                 xmlFile.delete();//删除文件
52             }
53         }
54 
55     }
56 }

1.7、因为创建文件会在项目中生成文件，我选择将文件放到临时文件夹

 1 package com.springboot.demo.utils;
 2 
 3 import java.io.File;
 4 
 5 /**
 6  * 在windows和linux系统下均可正常使用
 7  *
 8  */
 9 public class PathUtil {
10     //获取项目的根路径
11     public final static String classPath;
12 
13     static {
14         //获取的是classpath路径，适用于读取resources下资源
15 //        classPath = Thread.currentThread().getContextClassLoader().getResource("").getPath();
16         classPath = System.getProperty("user.dir");
17     }
18 
19     /**
20      * 项目根目录
21      */
22     public static String getRootPath() {
23         return RootPath("");
24     }
25 
26     /**
27      * 自定义追加路径
28      */
29     public static String getRootPath(String u_path) {
30         return RootPath("/" + u_path);
31     }
32 
33     /**
34      * 私有处理方法
35      */
36     private static String RootPath(String u_path) {
37         String rootPath = "";
38         //windows下
39         if ("\\".equals(File.separator)) {
40             //System.out.println(classPath);
41             rootPath = classPath + u_path;
42             rootPath = rootPath.replaceAll("/", "\\\\");
43             if (rootPath.substring(0, 1).equals("\\")) {
44                 rootPath = rootPath.substring(1);
45             }
46         }
47         //linux下
48         if ("/".equals(File.separator)) {
49             //System.out.println(classPath);
50             rootPath = classPath + u_path;
51             rootPath = rootPath.replaceAll("\\\\", "/");
52         }
53         return rootPath;
54     }
55 
56     //更多扩展方法任你发挥
57 
58 }

 1 package com.springboot.demo.utils;
 2 import java.io.File;
 3 import java.io.UnsupportedEncodingException;
 4 import java.net.URLDecoder;
 5 import java.nio.charset.StandardCharsets;
 6 /**
 7  * @author dingpl
 8  * @date 2021/7/13 10:25
 9  */
10 public class PathUtils {
11     /**
12      * 如果已打成jar包，则返回jar包所在目录
13      * 如果未打成jar，则返回target所在目录
14      * @return
15      */
16     public static String getRootPath() throws UnsupportedEncodingException {
17         // 项目的编译文件的根目录
18         String path = URLDecoder.decode(PathUtil.class.getResource("/").getPath(), String.valueOf(StandardCharsets.UTF_8));
19         if (path.startsWith("file:")) {
20             int i = path.indexOf(".jar!");
21             path = path.substring(0, i);
22             path = path.replaceFirst("file:", "");
23         }
24         // 项目所在的目录
25         return new File(path).getParentFile().getAbsolutePath();
26     }
27 
28 }

至此代码完成！

效果图：

2.1、点击下载按钮

2.2、文件内容

期待大家的指正！！！

package com.springboot.demo.utils;

import java.io.File;

/**
 * 在windows和linux系统下均可正常使用
 *
 */
public class PathUtil {
    //获取项目的根路径
public final static String classPath;

    static {
        //获取的是classpath路径，适用于读取resources下资源
//        classPath = Thread.currentThread().getContextClassLoader().getResource("").getPath();
classPath = System.getProperty("user.dir");
    }

    /**
     * 项目根目录
     */
public static String getRootPath() {
        return RootPath("");
    }

    /**
     * 自定义追加路径
     */
public static String getRootPath(String u_path) {
        return RootPath("/" + u_path);
    }

    /**
     * 私有处理方法
     */
private static String RootPath(String u_path) {
        String rootPath = "";
        //windows下
if ("\\".equals(File.separator)) {
            //System.out.println(classPath);
rootPath = classPath + u_path;
            rootPath = rootPath.replaceAll("/", "\\\\");
            if (rootPath.substring(0, 1).equals("\\")) {
                rootPath = rootPath.substring(1);
            }
        }
        //linux下
if ("/".equals(File.separator)) {
            //System.out.println(classPath);
rootPath = classPath + u_path;
            rootPath = rootPath.replaceAll("\\\\", "/");
        }
        return rootPath;
    }

    //更多扩展方法任你发挥

}

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