Use POI to export excel file, image URL to export file, image and excel file to export compressed package

I recently made a excel Export function , Fields involve pictures . But the demand is ： Export a compressed package , The compressed package contains a excel Files and multiple pictures , Image naming is unique according to business .

preparation

Entity class

public class MessageDO {
    
    private Integer id;
    @ExcelExport(" cover ")
    private String url;
    @ExcelExport(" title ")
    private String title;
    @ExcelExport(" Content ")
    private String content;
    @ExcelExport(" Creation time ")
    private LocalDateTime createTime;
    @ExcelExport(" Update time ")
    private LocalDateTime updateTime;
    // Omit get、set Method 
    //..............
}

Test data

private List<MessageDO> getList() {
    
        List<MessageDO> messageDOS = new ArrayList<>();
        List<String> urlList = Arrays.asList("https://img-blog.csdnimg.cn/20210823171755669.png",
                "https://img-blog.csdnimg.cn/20210705113753337.jpeg",
                "https://img-blog.csdnimg.cn/20210823085631276.jpeg",
                "https://img-blog.csdnimg.cn/20210823085620179.jpeg",
                "https://img-blog.csdnimg.cn/2021082308560694.jpeg");
        for (int i = 0; i < 5; i++) {
    
            MessageDO messageDO = new MessageDO();
            messageDO.setTitle(" This is the test title " + i);
            messageDO.setContent(" This is the test content " + i);
            messageDO.setUrl(urlList.get(i));
            messageDO.setCreateTime(LocalDateTime.now());
            messageDO.setUpdateTime(LocalDateTime.now());
            messageDOS.add(messageDO);
        }
        return messageDOS;
    }

Export what I use here is POI, I found one online to use POI Import and export articles , It's written very well .

Link to the original text ：Java Realization Excel Import and export , Just read this one ( Collector's Edition )

This link provides many methods , If I want to use the export function , Directly use the one provided inside ExcelUtils Just tools .

maven rely on

<!-- POI -->
<dependency>
    <groupId>org.apache.poi</groupId>
    <artifactId>poi-ooxml</artifactId>
    <version>3.16</version>
</dependency>
<dependency>
    <groupId>commons-lang</groupId>
    <artifactId>commons-lang</artifactId>
    <version>2.6</version>
    <scope>compile</scope>
</dependency>
<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>fastjson</artifactId>
    <version>1.2.47</version>
    <scope>compile</scope>
</dependency>

export excel

from the shallower to the deeper , The first is to realize the basic export function .

Control end code ：

/** *  Normal export  * @param response */
@GetMapping("exportExcel")
public void exportExcel(HttpServletResponse response) {
    
    List<MessageDO> messageDOS = getList();
    ExcelUtils.export(response, " export ", messageDOS, MessageDO.class);
}

The effect is as follows ：

This completes the ordinary excel export , Is it simple . It mainly uses the tool class of reference link .

Transfer the image address to the file download and package it into a compressed file

Generally, when we save pictures , Just save one url route .

My need is ： according to url Download the pictures through the path , Put it in a compressed package .

Here I offer a FileUtil Tool class .

The process is divided into three steps ：

1. adopt url Link to download the file locally .
2. Compress it into zip file .
3. Delete the locally downloaded files .

The tool class code is as follows ：

public class FileUtil{
    
    /** *  adopt url Download files to local  * @param url  network address  * @return */
    public static File getFileByUrl(String url) {
    
        // Name local files 
        String fileName = url.substring(url.lastIndexOf("."));
        File file = null;
        URL urlfile;
        InputStream inStream = null;
        OutputStream os = null;
        try {
    
            file = File.createTempFile(System.currentTimeMillis() + "", fileName);
            // download 
            urlfile = new URL(url);
            inStream = urlfile.openStream();
            os = new FileOutputStream(file);

            int bytesRead = 0;
            byte[] buffer = new byte[8192];
            while ((bytesRead = inStream.read(buffer, 0, 8192)) != -1) {
    
                os.write(buffer, 0, bytesRead);
            }
        } catch (Exception e) {
    
            e.printStackTrace();
        } finally {
    
            try {
    
                if (null != os) {
    
                    os.close();
                }
                if (null != inStream) {
    
                    inStream.close();
                }
            } catch (Exception e) {
    
                e.printStackTrace();
            }
        }

        return file;
    }

    /** *  function : Compress multiple files , Output compressed zip File stream  * @param zipFileName zip file name  * @param files  Exported files  * @param imgNameList  file name  * @param response * @throws Exception */
    public static void downZip(String zipFileName, List<File> files, List<String> imgNameList,
                               HttpServletResponse response) throws Exception {
    
        byte[] buf = new byte[1024];
        //  Get the output stream 
        BufferedOutputStream bos = null;
        try {
    
            bos = new BufferedOutputStream(response.getOutputStream());
        } catch (IOException e) {
    
            e.printStackTrace();
        }
        ZipOutputStream out = null;
        try {
    
            // An emphasis on 
            response.reset();
            //  Different types of files correspond to different MIME type 
            response.setContentType("application/octet-stream");
            response.setCharacterEncoding("utf-8");
            response.setHeader("Content-disposition", "attachment;filename*=utf-8''" + zipFileName + ".zip");
            response.setContentType("application/octet-stream;charset=UTF-8");
            //ZipOutputStream class ： Complete the compression of files or folders 
            out = new ZipOutputStream(bos);

            for (int i = 0; i < files.size(); i++) {
    
                FileInputStream in = new FileInputStream(files.get(i));
                // Name the files in the list separately 
                // To obtain the suffix 
                String imgUrl = files.get(i).getName();
                String imgSuffix = imgUrl.substring(imgUrl.lastIndexOf("."));
                out.putNextEntry(new ZipEntry(imgNameList.get(i) + imgSuffix));
                int len;
                while ((len = in.read(buf)) > 0) {
    
                    out.write(buf, 0, len);
                }
                in.close();
                out.closeEntry();
            }
        } catch (Exception e) {
    
            e.printStackTrace();
        } finally {
    
            if (Objects.nonNull(out)) {
    
                out.flush();
                out.close();
            }
            if (Objects.nonNull(bos)) {
    
                bos.close();
            }
            // Delete file 
            delete(files);
        }
    }

    /** *  Local file delete  * @param files  Multiple files  */
    private static void delete(List<File> files) {
    
        for (File file : files) {
    
            file.delete();
        }
    }
}

Control end code ：

/** *  Through multiple pictures url Path download zip file  * @param response * @throws Exception */
    @GetMapping("exportImgZip")
    public void exportImgZip(HttpServletResponse response) throws Exception {
    
        List<MessageDO> messageDOS = getList();
        List<File> fileList = new ArrayList<>();
        for (MessageDO messageDO : messageDOS) {
    
            File file = FileUtil.getFileByUrl(messageDO.getUrl());
            fileList.add(file);
        }
        List<String> nameList = Arrays.asList(" picture 1", " picture 2", " picture 3", " picture 4", " picture 5");
        FileUtil.downZip("record", fileList, nameList, response);
    }

Just ask for access .

After unzipping, you can see the picture .

hold excel Files and picture files are packed together into zip

Need to put excel The files and pictures are put in a compressed package , The content is ： One excel、 More pictures , In a compressed package file .

Here we are. , In fact, according to the tool class I provided above, you can also guess how to implement . Because I have constantly optimized the tool class .

Ideas ：

1. export excel To local , Get the local path .
2. Download pictures to local , Get the local path .
3. Path summary , Export zip file .

That's it excel And pictures url Export of zip Format file .

The specific control end code is as follows ：

@GetMapping("exportZip")
public void exportZip(HttpServletResponse response) throws Exception {
    
    List<MessageDO> messageDOS = getList();
    if (messageDOS.isEmpty()) {
    
        return;
    }
    String name = System.currentTimeMillis() + ".xlsx";
    String fileName = "D:\\" + name;
    ExcelUtils1.export1(fileName, " news ", messageDOS, MessageDO.class);
    List<File> fileList = new ArrayList<>();
    for (MessageDO messageDO : messageDOS) {
    
        File file = FileUtil.getFileByUrl(messageDO.getUrl());
        fileList.add(file);
    }
    File excelFile = new File(fileName);
    fileList.add(excelFile);
    List<String> nameList = Arrays.asList(" picture 1", " picture 2", " picture 3", " picture 4", " picture 5", " news excel");
    FileUtil.downZip("record", fileList, nameList, response);
}

Calls to perform ：

Unzip to see ：

thus , This requirement is realized .

Careful friends may find two places ：1. excel I used the tools of ExcelUtils1.export1 .2. there excel I specified the path when exporting .

In fact, the export does not change anything , Change to local export , Small partners can realize it by themselves .

The path is specified to obtain the path , You can also use other methods .

At present, it is realized in this way , If there is a better method to optimize later . Friends can also put forward ideas .