有时需要给poi导出的excel添加水印及设置打印是默认的一些参数。在此记录下。

在此使用的poi的接口是 org.apache.poi.xssf.usermodel.XSSFWorkbook; HSSFWorkbook不行，试过了。

package com.southgroup.psimp.util;

import java.awt.Color;
import java.awt.Font;
import java.awt.FontMetrics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.Transparency;
import java.awt.image.BufferedImage;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.Date;

import javax.imageio.ImageIO;

import org.apache.poi.POIXMLDocumentPart;
import org.apache.poi.openxml4j.opc.PackagePartName;
import org.apache.poi.openxml4j.opc.PackageRelationship;
import org.apache.poi.openxml4j.opc.TargetMode;
import org.apache.poi.xssf.usermodel.XSSFRelation;
import org.apache.poi.xssf.usermodel.XSSFSheet;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;

/**
 * 添加水印
 * @author Jfei
 *
 */
public class WaterMarkUtil {
	/**
	 * 坪山项目excel导出添加水印
	 * @param workbook
	 * @throws IOException
	 */
	public static void insertWaterMarkTextToXlsx(XSSFWorkbook workbook) throws IOException{
		String s = "XXXX项目管理系统";
		String userName = UserUtil.getUser().getUserName();
		String date = DateUtils.dateToString(new Date(), "yyyy-MM-dd");
		String waterMarkText = s + "\n"+userName+"  "+date;
		insertWaterMarkTextToXlsx(workbook,waterMarkText);
	}
	/**
	 * 给excel添加水印
	 * @throws IOException 
	 */
	public static void insertWaterMarkTextToXlsx(XSSFWorkbook workbook,String waterMarkText) throws IOException{
		BufferedImage image = createWatermarkImage(waterMarkText);
		ByteArrayOutputStream imageOs = new ByteArrayOutputStream();
		ImageIO.write(image, "png", imageOs);
		int pictureIdx = workbook.addPicture(imageOs.toByteArray(), XSSFWorkbook.PICTURE_TYPE_PNG);
		POIXMLDocumentPart poixmlDocumentPart = workbook.getAllPictures().get(pictureIdx);
		for (int i = 0; i < workbook.getNumberOfSheets(); i++) {//获取每个Sheet表
            XSSFSheet sheet = workbook.getSheetAt(i);
            PackagePartName ppn = poixmlDocumentPart.getPackagePart().getPartName();
            String relType = XSSFRelation.IMAGES.getRelation();
            PackageRelationship pr = sheet.getPackagePart().addRelationship(ppn, TargetMode.INTERNAL, relType, null);
            sheet.getCTWorksheet().addNewPicture().setId(pr.getId());
        }
	}
	
	public static BufferedImage createWatermarkImage(String waterMark){
	    String[] textArray = waterMark.split("\n");
        Font font = new Font("microsoft-yahei", Font.PLAIN, 32);
        Integer width = 500;
        Integer height = 400;

        BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
        // 背景透明 开始
        Graphics2D g = image.createGraphics();
        image = g.getDeviceConfiguration().createCompatibleImage(width, height, Transparency.TRANSLUCENT);
        g.dispose();
        // 背景透明 结束
        g = image.createGraphics();
        g.setColor(new Color(Color.lightGray.getRGB()));// 设定画笔颜色
        g.setFont(font);// 设置画笔字体
     //   g.shear(0.1, -0.26);// 设定倾斜度

//        设置字体平滑
        g.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
        
      //文字从中心开始输入，算出文字宽度，左移动一半的宽度，即居中
		FontMetrics fontMetrics = g.getFontMetrics(font);
		
		// 水印位置
		int x = width / 2;
		int y = height / 2;
		// 设置水印旋转
		g.rotate(Math.toRadians(-40), x,y);
        for (int i = 0; i < textArray.length; i++) {
        	// 文字宽度
			int textWidth = fontMetrics.stringWidth(textArray[i]);
            g.drawString(textArray[i], x-(textWidth/2), y);// 画出字符串
            y = y + font.getSize();
        }

        g.dispose();// 释放画笔
        return image;
}
}

设置打印时默认参数

	/**
	 * 设置打印的参数
	 * @param wb
	 */
	private static void setPrintParams(XSSFWorkbook wb){
		XSSFSheet sheet = wb.getSheetAt(0);
		XSSFPrintSetup printSetup = sheet.getPrintSetup();
		// 打印方向，true：横向，false：纵向(默认
		printSetup.setLandscape(true); 
      //设置A4纸
        printSetup.setPaperSize(XSSFPrintSetup.A4_PAPERSIZE);
     // 将整个工作表打印在一页（缩放）,如果行数很多的话，可能会出问题
    //    sheet.setAutobreaks(true);
        //将所有的列调整为一页，行数多的话，自动分页
        printSetup.setScale((short)70);//缩放的百分比，自行调整
        sheet.setAutobreaks(false);
        
	}

导出来的水印效果，水印不会遮住内容，点击水印上的单元格，仍然可以编辑