使用POI编辑Word文档添加文字水印

背景

近期客户提出一个上传文件时自动添加文字水印的功能，其中关于word文档加水印，网上现有的解决方案都有问题，本文参考java实现word文档(docx)添加水印这篇博客，解决了文档存在分页符情况下无法给所有分页添加水印的问题。
由于POI对于doc格式支持较少，暂时未找到合适的解决doc格式文档添加水印的方法，本文只针对于docx格式文档，如果有大佬有可行方案，欢迎留言交流，感激不尽。

依赖

核心依赖就是POI相关包

<dependency>
    <groupId>org.apache.poigroupId>
    <artifactId>poiartifactId>
    <version>${poi.version}version>
dependency>
<dependency>
    <groupId>org.apache.poigroupId>
    <artifactId>poi-ooxmlartifactId>
    <version>${poi-ooxml.version}version>
dependency>
<dependency>
    <groupId>org.apache.poigroupId>
    <artifactId>poi-ooxml-schemasartifactId>
    <version>${poi-ooxml-schemas.version}version>
dependency>

实现代码

说明：

• 使用本段代码需要确保服务器正确包含对应字体, 默认使用Arial字体
• 本段代码参考了POI中org.apache.poi.xwpf.model.XWPFHeaderFooterPolicy#createWatermark的实现

import com.microsoft.schemas.office.office.CTLock;
import com.microsoft.schemas.vml.CTGroup;
import com.microsoft.schemas.vml.CTShape;
import com.microsoft.schemas.vml.CTShapetype;
import com.microsoft.schemas.vml.CTTextPath;
import com.microsoft.schemas.vml.STExt;
import com.microsoft.schemas.vml.STTrueFalse;
import org.apache.poi.util.IOUtils;
import org.apache.poi.xwpf.usermodel.XWPFDocument;
import org.apache.poi.xwpf.usermodel.XWPFHeader;
import org.apache.poi.xwpf.usermodel.XWPFParagraph;
import org.openxmlformats.schemas.wordprocessingml.x2006.main.CTP;
import org.openxmlformats.schemas.wordprocessingml.x2006.main.CTPPr;
import org.openxmlformats.schemas.wordprocessingml.x2006.main.CTPicture;
import org.openxmlformats.schemas.wordprocessingml.x2006.main.CTR;
import org.openxmlformats.schemas.wordprocessingml.x2006.main.CTRPr;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.nio.file.Files;
import java.nio.file.Paths;

public class DocxTest {

   public void addWatermark(InputStream is, OutputStream os, String waterMark) throws IOException {
       XWPFDocument doc = new XWPFDocument(is);
       // 遍历文档，添加水印
       waterMarkDocxDocument(doc, waterMark);
       try {
           doc.write(os);
       }
       finally {
           IOUtils.closeQuietly(doc);
       }
   }

   /**
    * 为文档添加水印

    * 实现参考了{@link org.apache.poi.xwpf.model.XWPFHeaderFooterPolicy#createWatermark(String)}
    *
    * @param doc 需要被处理的docx文档对象
    * @param waterMark 水印内容
    */
   private void waterMarkDocxDocument(XWPFDocument doc, String waterMark) {
       // 获取文档的所有页眉，如果文档没有页眉，则新建一个默认页眉
       List<XWPFHeader> headerList = new ArrayList<>(doc.getHeaderList());
       if (headerList.isEmpty()) {
           headerList.add(doc.createHeader(HeaderFooterType.DEFAULT));
       }
       // 遍历所有的header，这里包含所有的分页
       for (XWPFHeader header : headerList) {
           int size = header.getParagraphs().size();
           if (size == 0) {
               header.createParagraph();
           }
           XWPFParagraph paragraph = header.getParagraphArray(0);
           CTP ctp = paragraph.getCTP();
           byte[] rsidR = doc.getDocument().getBody().getPArray(0).getRsidR();
           byte[] rsidRDefault = doc.getDocument().getBody().getPArray(0).getRsidRDefault();
           ctp.setRsidP(rsidR);
           ctp.setRsidRDefault(rsidRDefault);
           CTPPr ppr = ctp.addNewPPr();
           ppr.addNewPStyle().setVal("Header");
           // 开始加水印
           CTR ctr = ctp.addNewR();
           CTRPr ctrpr = ctr.addNewRPr();
           ctrpr.addNewNoProof();
           CTGroup group = CTGroup.Factory.newInstance();
           CTShapetype shapeType = group.addNewShapetype();
           CTTextPath shapeTypeTextPath = shapeType.addNewTextpath();
           shapeTypeTextPath.setOn(STTrueFalse.T);
           shapeTypeTextPath.setFitshape(STTrueFalse.T);
           CTLock lock = shapeType.addNewLock();
           lock.setExt(STExt.VIEW);
           CTShape shape = group.addNewShape();
           shape.setId("PowerPlusWaterMarkObject");
           shape.setSpid("_x0000_s102");
           shape.setType("#_x0000_t136");
           // 设置形状样式（旋转，位置，相对路径等参数）
           shape.setStyle(getShapeStyle());
           shape.setFillcolor("#d8d8d8");
           // 字体设置为实心
           shape.setStroked(STTrueFalse.FALSE);
           // 绘制文本的路径
           CTTextPath shapeTextPath = shape.addNewTextpath();
           // 设置文本字体与大小
           shapeTextPath.setStyle("font-family:Arial;font-size:1pt");
           shapeTextPath.setString(waterMark);
           CTPicture pict = ctr.addNewPict();
           pict.set(group);
       }
   }

   /**
    * 构建Shape的样式参数
    */
   private String getShapeStyle() {
       // 文本path绘制的定位方式
       return "position: " + "absolute" +
               ";margin-top: " + 0 +
               ";width: " + "415pt" +
               ";height: " + "207.5pt" +
               ";z-index: " + "-251654144" +
               ";mso-wrap-edited: " + "f" +
               ";mso-position-horizontal: " + "center" +
               ";mso-position-horizontal-relative: " + "margin" +
               ";mso-position-vertical-relative: " + "margin" +
               ";mso-position-vertical: " + "center" +
               ";rotation: " + 315;
   }

   public static void main(String[] args) throws IOException {
       InputStream is = Files.newInputStream(Paths.get("test.docx"));
       OutputStream os = Files.newOutputStream(Paths.get("testOut.docx"));
       DocxTest docxTest = new DocxTest();
       docxTest.addWatermark(is, os, "WATER MARK");
   }

}

效果