java项目中利用OpenOffice实现预览

核心jar包
看了不少帖子，引用的也不一样，使用后我采用的这两个，其他IO包都会涉及。

<!-- 利用openoffice文件转为PDF -->
<dependency>
    <groupId>com.google.guava</groupId>
    <artifactId>guava</artifactId>
       <version>19.0</version>
</dependency>
<dependency>
    <groupId>com.github.livesense</groupId>
    <artifactId>jodconverter-core</artifactId>
    <version>1.0.5</version>
</dependency>

工具类
工具类有很多种，也是根据不同的需求，有的转成HTML、PDF等等。对于服务的调用也不尽相同。我是直接代码调用服务，没有服务时候打开服务。代码中的安装位置是默认的，根据实际修改，注意版本问题

package net.cnki.util;

import java.io.File;
import java.util.Date;
import java.util.HashMap;
import java.util.Map;
import java.util.regex.Pattern;

import org.artofsolving.jodconverter.OfficeDocumentConverter;
import org.artofsolving.jodconverter.office.DefaultOfficeManagerConfiguration;
import org.artofsolving.jodconverter.office.ExternalOfficeManagerConfiguration;
import org.artofsolving.jodconverter.office.OfficeException;
import org.artofsolving.jodconverter.office.OfficeManager;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * 
 * @author ZhiPengyu
 * @ClassName:    [OpenofficeUtil]
 * @Description:  [调用openoffice服务，进行文件预览]
 * 在程序安装目录下执行以下启动服务：soffice -headless -accept="socket,host=127.0.0.1,port=8100;urp;" -nofirststartwizard & 
 * @CreateDate:   [2022年03月24日 下午3:21:06]
 */
public class OpenofficeUtil {
    static Logger logger = LoggerFactory.getLogger(OpenofficeUtil.class);
    private static String officeHome = getOfficeHome();
    private static int port = 8100;// 这里的内容是根据你的系统选择不同的端口号，windows系统的端口号是8100
    private static OfficeManager officeManager; // 尝试连接已存在的服务器
                                                
    // openoffice的安装地址
    private static String getOfficeHome() {
        String osName = System.getProperty("os.name");
        if (Pattern.matches("Linux.*", osName)) {
            return "/opt/openoffice4";
        } else if (Pattern.matches("Windows.*", osName)) {
            return "C:/Program Files (x86)/OpenOffice 4";
        } else if (Pattern.matches("Mac.*", osName)) {
            return "/Application/OpenOffice.org.app/Contents";
        }
        return null;
    }

    private static boolean reconnect() {
        try {
            // 尝试连接openoffice的已存在的服务器
            ExternalOfficeManagerConfiguration externalProcessOfficeManager = new ExternalOfficeManagerConfiguration();
            externalProcessOfficeManager.setConnectOnStart(true);
            externalProcessOfficeManager.setPortNumber(8100);
            officeManager = externalProcessOfficeManager.buildOfficeManager();
            officeManager.start();
            return true;
        } catch (OfficeException e) {
            e.printStackTrace();
            return false;
        }

    }

// 开启新的openoffice的进程
    private static void start() {
        logger.debug("启动OpenOffice服务");
        try {
            DefaultOfficeManagerConfiguration configuration = new DefaultOfficeManagerConfiguration();
            configuration.setOfficeHome(officeHome);// 安装地址
            configuration.setPortNumbers(port);// 端口号
            configuration.setTaskExecutionTimeout(1000 * 60 * 5);// 设置任务执行超时为5分钟
            configuration.setTaskQueueTimeout(1000 * 60 * 60 * 24);// 设置任务队列超时为24小时
            officeManager = configuration.buildOfficeManager();
            officeManager.start(); // 启动服务
        } catch (Exception e) {
            logger.error("启动OpenOffice服务出错" + e);
        }
    }

// 使用完需要关闭该进程
    private static void stop() {
        logger.debug("关闭OpenOffice服务");
        try {
            if (officeManager != null)
                officeManager.stop();
        } catch (Exception e) {
            logger.error("关闭OpenOffice服务出错" + e);
        }
    }

    /**
     * 转换入口
     * @param inputFilePath 转换前文件全路径
     * @param outputFilePath 转换后文件全路径
     * @return
     */
    public static Map<String, Object> convertToPdf(String inputFilePath, String outputFilePath) {
        Map<String, Object> tResultMap = new HashMap<>();
        tResultMap.put("status", "fail");
        long begin_time = new Date().getTime();
        File inputFile = null;
        File outFile = null;
        try { // 如果已存在的服务不能连接或者不存在服务，那么开启新的服务
            if (!reconnect()) {
                start();// 开启服务
            }
            inputFile = new File(inputFilePath);
            outFile = new File(outputFilePath);
            logger.info("开始转换文档：" + inputFilePath + "=>" + outputFilePath);
            OfficeDocumentConverter converter = new OfficeDocumentConverter(officeManager);
            converter.convert(inputFile, outFile); // 转换文档
            long end_time = new Date().getTime();
            logger.info("文件转换耗时：[" + (end_time - begin_time) + "]ms");
        } catch (Exception e) {
            logger.error("转换文档出错" + e);
            outFile = null;
        } finally {
            logger.info("结束转换文档");
            stop();
        }
        tResultMap.put("result", outputFilePath);
        tResultMap.put("status", "success");
        return tResultMap;
    }

    // 测试工具类是否成功
    /*
     * public static void main(String[] args) { File sf = PdfUtils.convertToPdf(
     * "C:\\Users\\Administrator\\Desktop\\TestFile\\singleFile\\立项论证报告书-中国海油科技情报收集及共享应用研究.docx"
     * ); //File sf = new File("E:/test.ppt"); System.out.println(sf.getPath()); }
     */

}

controller层调用
以下代码我加入了异常拦截、参数加密，都不用管。直接调用工具类就行。前台用的a标签，跳转新页，url会有参数明文，看个人处理吧。已转换的就直接用就行

@RequestMapping("/fileview")
    public void fileview(String filePdf,HttpServletRequest request, HttpServletResponse response) throws IOException, PreviewException  {
        //String materialId = request.getParameter("materialId");
        logger.info("文件预览功能！");
        if(ParametersUtil.isBlank(filePdf)) {
            throw new PreviewException("预览文件未找到！");
        }
        byte[] decodedBytes = Base64.getDecoder().decode(filePdf);
        String decodedString = new String(decodedBytes, Charset.defaultCharset());
        int materialid = Integer.valueOf(decodedString);
        ProjectMaterial mateProject = projectMaterialService.selectByPrimaryKey(materialid);
        if(mateProject == null) {
            throw new PreviewException("预览文件未找到！");
        }
        String inputFilePath = mateProject.getMaterialPath();
        String[] extensions = inputFilePath.split("\\.");
        String extension = extensions[extensions.length - 1].toLowerCase();//并转为小写
        Map<String, Object> mapData= new HashMap<>();
                
        if("pdf".equals(extension)) {
            mapData.put("status", "success");
            mapData.put("result", inputFilePath);
        }else {
            File file = new File(fileEntity.getFileToPdfPath());
            if (!file.exists()) {
                file.mkdirs();
            }
            File file1 = new File(inputFilePath);
            if(!file1.exists()) {
                throw new PreviewException("预览文件未找到！");
            }
            //去掉拓展名
            String fileanmes = file1.getName().substring(0, file1.getName().lastIndexOf("."));
            String outputFilePath = fileEntity.getFileToPdfPath()+fileanmes+"_"+extension+".pdf";
            File checkFile = new File(outputFilePath);
            if (checkFile.exists()) {
                mapData.put("status", "success");
                mapData.put("result", outputFilePath);
            }else {
                //mapData= ConverterUtil.openOfficeToPDF(inputFilePath, outputFilePath);
                mapData = OpenofficeUtil.convertToPdf(inputFilePath, outputFilePath);
            }
        }
        //得到id，查库获取文件名称
        InputStream input = null;
        OutputStream out = null;
        
        String status = (String) mapData.get("status");
        String filePath = "";
        if("success".equals(status)) {
            filePath = (String) mapData.get("result");
        }else {
            filePath="";
        }
        
        File file = new File(filePath);
        try {
            input = new FileInputStream(file);
            response.setContentType("application/pdf");
            out = response.getOutputStream();

            byte[] b = new byte[512];
            if (out != null) {
                if (input != null) {
                    while ((input.read(b)) != -1) {
                        out.write(b);
                    }
                }
            }

            out.flush();
        } catch (FileNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
            logger.error(e.toString());
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
            logger.error(e.toString());
        }finally {
            input.close();
            out.close();
        }
        
        
    }

问题总结
1、调用转换的效率问题
之前采用代码打开服务并不指定端口的方式执行起来效率会很慢，十几秒才转换完。因此，建议指定端口并提前开启服务，会快很多，用户体验也很好

2、启动服务的问题
启动时，不论是否后台开启服务，看你的命令是否在安装目录下，没有在目录下的话，命令前要写好安装位置。