Java-实现word、excel、ppt、txt等在线预览

比眉伴天荒 2024-03-24 12:24 54阅读 0赞

Java实现办公文件在线预览功能是一个大家在工作中也许会遇到的需求，网上些公司专门提供这样

的服务，不过需要收费 如果想要免费的，可以用openoffice，实现原理就是：

通过第三方工具openoffice，将word、excel、ppt、txt等文件转换为pdf文件流

这里介绍通过poi实现word、excel、ppt转pdf流，这样就可以在浏览器上实现预览了。

1.到官网下载openoffice安装包，安装运行

[Apache OpenOffice - Official Download][]

![3517cbdfed26432aa6320b7a972cd669.png][]

2.引入依赖

<dependency>
        <groupId>com.artofsolving</groupId>
        <artifactId>jodconverter</artifactId>
        <version>2.2.1</version>
    </dependency>

3. 将word、excel、ppt、txt等文件转换为pdf文件流

import com.artofsolving.jodconverter.DefaultDocumentFormatRegistry;
    import com.artofsolving.jodconverter.DocumentConverter;
    import com.artofsolving.jodconverter.DocumentFormat;
    import com.artofsolving.jodconverter.openoffice.connection.OpenOfficeConnection;
    import com.artofsolving.jodconverter.openoffice.connection.SocketOpenOfficeConnection;
    import com.artofsolving.jodconverter.openoffice.converter.StreamOpenOfficeDocumentConverter;
     
    import java.io.*;
    import java.net.HttpURLConnection;
    import java.net.URL;
    import java.net.URLConnection;
     
     
    /**
     * 文件格式转换工具类
     *
     * @version 1.0
     * @since JDK1.8
     */
    public class FileConvertUtil {
        /** 默认转换后文件后缀 */
        private static final String DEFAULT_SUFFIX = "pdf";
        /** openoffice_port */
        private static final Integer OPENOFFICE_PORT = 8100;
     
        /**
         * 方法描述 office文档转换为PDF(处理本地文件)
         *
         * @param sourcePath 源文件路径
         * @param suffix     源文件后缀
         * @return InputStream 转换后文件输入流
         * @author tarzan
         */
        public static InputStream convertLocaleFile(String sourcePath, String suffix) throws Exception {
            File inputFile = new File(sourcePath);
            InputStream inputStream = new FileInputStream(inputFile);
            return covertCommonByStream(inputStream, suffix);
        }
     
        /**
         * 方法描述  office文档转换为PDF(处理网络文件)
         *
         * @param netFileUrl 网络文件路径
         * @param suffix     文件后缀
         * @return InputStream 转换后文件输入流
         * @author tarzan
         */
        public static InputStream convertNetFile(String netFileUrl, String suffix) throws Exception {
            // 创建URL
            URL url = new URL(netFileUrl);
            // 试图连接并取得返回状态码
            URLConnection urlconn = url.openConnection();
            urlconn.connect();
            HttpURLConnection httpconn = (HttpURLConnection) urlconn;
            int httpResult = httpconn.getResponseCode();
            if (httpResult == HttpURLConnection.HTTP_OK) {
                InputStream inputStream = urlconn.getInputStream();
                return covertCommonByStream(inputStream, suffix);
            }
            return null;
        }
     
        /**
         * 方法描述  将文件以流的形式转换
         *
         * @param inputStream 源文件输入流
         * @param suffix      源文件后缀
         * @return InputStream 转换后文件输入流
         * @author tarzan
         */
        public static InputStream covertCommonByStream(InputStream inputStream, String suffix) throws Exception {
            ByteArrayOutputStream out = new ByteArrayOutputStream();
            OpenOfficeConnection connection = new SocketOpenOfficeConnection(OPENOFFICE_PORT);
            connection.connect();
            DocumentConverter converter = new StreamOpenOfficeDocumentConverter(connection);
            DefaultDocumentFormatRegistry formatReg = new DefaultDocumentFormatRegistry();
            DocumentFormat targetFormat = formatReg.getFormatByFileExtension(DEFAULT_SUFFIX);
            DocumentFormat sourceFormat = formatReg.getFormatByFileExtension(suffix);
            converter.convert(inputStream, sourceFormat, out, targetFormat);
            connection.disconnect();
            return outputStreamConvertInputStream(out);
        }
     
        /**
         * 方法描述 outputStream转inputStream
         *
         * @author tarzan
         */
        public static ByteArrayInputStream outputStreamConvertInputStream(final OutputStream out) throws Exception {
            ByteArrayOutputStream baos=(ByteArrayOutputStream) out;
            return new ByteArrayInputStream(baos.toByteArray());
        }
     
     
     
        public static void main(String[] args) throws IOException {
            //convertNetFile("http://172.16.10.21/files/home/upload/department/base/201912090541573c6abdf2394d4ae3b7049dcee456d4f7.doc", ".pdf");
            //convert("c:/Users/admin/Desktop/2.pdf", "c:/Users/admin/Desktop/3.pdf");
        }
    }

4.service层代码

/**
     * @Description:系统文件在线预览接口
     * @Author: tarzan
     */
    public void onlinePreview(String url, HttpServletResponse response) throws Exception {
            //获取文件类型
            String[] str = SmartStringUtil.split(url,"\\.");
     
            if(str.length==0){
                throw new Exception("文件格式不正确");
            }
            String suffix = str[str.length-1];
            if(!suffix.equals("txt") && !suffix.equals("doc") && !suffix.equals("docx") && !suffix.equals("xls")
                    && !suffix.equals("xlsx") && !suffix.equals("ppt") && !suffix.equals("pptx")){
                throw new Exception("文件格式不支持预览");
            }
            InputStream in=FileConvertUtil.convertNetFile(url,suffix);
            OutputStream outputStream = response.getOutputStream();
            //创建存放文件内容的数组
            byte[] buff =new byte[1024];
            //所读取的内容使用n来接收
            int n;
            //当没有读取完时,继续读取,循环
            while((n=in.read(buff))!=-1){
                //将字节数组的数据全部写入到输出流中
                outputStream.write(buff,0,n);
            }
            //强制将缓存区的数据进行输出
            outputStream.flush();
            //关流
            outputStream.close();
            in.close();
    }

5.controller层代码

@ApiOperation(value = "系统文件在线预览接口 by tarzan")
    @PostMapping("/api/file/onlinePreview")
    public void onlinePreview(@RequestParam("url") String url, HttpServletResponse response) throws Exception{
            fileService.onlinePreview(url,response);
    }

[Apache OpenOffice - Official Download]: http://www.openoffice.org/download/index.html
[3517cbdfed26432aa6320b7a972cd669.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/24/7ef1a515985e4f26a5b56eb0bea00071.png