JAVA后端生成类似于分享海报图片的功能的实现

首先确定一下我们需要实现的效果图

案例图

核心代码如下：

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.Rectangle;
import java.awt.RenderingHints;
import java.awt.Toolkit;
import java.awt.geom.Ellipse2D;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.math.BigDecimal;
import java.net.URL;

import javax.imageio.ImageIO;


public void drawCouponPosterImage(String host, Long userId, GoodsInfoVO vo,String filePath)  {
		try {
			String pngString = vo.getPicUrl().substring(vo.getPicUrl().length() - 3);
			String savePath = ZshopConstants.UploadFilesConstants.STATICFILESTEMPPATH;
			String imageName = System.currentTimeMillis() + ".png";
			if (pngString.equals("png")) {
				URL url = new URL(vo.getPicUrl());
				InputStream is = url.openStream();
				byte[] buffer = new byte[1024];
				int len = 0;

				File imageFile = new File(savePath + File.separator + imageName);
				OutputStream os = new FileOutputStream(imageFile);
				if (!imageFile.exists()) {
					imageFile.mkdirs();
				}
				while ((len = is.read(buffer)) != -1) {
					os.write(buffer, 0, len);
				}
				os.close();
				is.close();
				System.out.println("保存图片");
			}

			JSONObject json = new JSONObject();
			json.put("userId", userId);
			json.put("goodsId", vo.getGoodsId());

			// 平台
			String platPath = host + "/resources/images/invite/taobao.png";
			if ("tmall".equals(vo.getFrom())) {
				platPath = host + "/resources/images/invite/tianmao.png";
			} else if ("jd".equals(vo.getFrom())) {
				platPath = host + "/resources/images/invite/jd.png";
			} else if ("pdd".equals(vo.getFrom())) {
				platPath = host + "/resources/images/invite/pdd.png";
			}
			BufferedImage platImage = ImageIO.read(new URL(platPath));

			// 透明底
			BufferedImage bg = new BufferedImage(750, 1250, BufferedImage.TYPE_INT_RGB);
			Graphics2D g = bg.createGraphics();
			g.setColor(Color.WHITE);
			g.fillRect(0, 0, 750, 1250);// 填充整个屏幕
			g.setRenderingHint(RenderingHints.KEY_ANTIALIASING,         RenderingHints.VALUE_ANTIALIAS_ON);						// 消除画图锯齿
			g.setRenderingHint(RenderingHints.KEY_TEXT_ANTIALIASING, RenderingHints.VALUE_TEXT_ANTIALIAS_ON);	// 消除文字锯齿
			
			// 写入商品图
			Image src = Toolkit.getDefaultToolkit().getImage(new URL(vo.getPicUrl()));
			BufferedImage goodsImg = BufferedImageBuilder.toBufferedImage(src);
			if (pngString.equals("png")) {	// png单独处理
				String strImg = ZshopConstants.UploadFilesConstants.STATICFILESTEMPPATH + File.separator + imageName;
				goodsImg = ImageIO.read(new File(strImg));
			}
			int y = 10;
			Rectangle rectangle = new Rectangle(10, y, 730, 730);
			g.drawImage(goodsImg.getScaledInstance(rectangle.width, rectangle.height, Image.SCALE_SMOOTH), rectangle.x, rectangle.y, null);
	        y+=735;
			
			// 优惠券背景
	        String couponPath = host + "/resources/images/invite/goodsDetailCoupon.png";
			BufferedImage couponImg = ImageIO.read(new URL(couponPath));
			g.drawImage(couponImg.getScaledInstance(730, 158, Image.SCALE_SMOOTH), 10, y+10, 730, 158, null);
			y+=75;
			
			Double price = -1.0;
			Double rebatePrice = 0.0;
			try{
				rebatePrice =  (Double.valueOf(vo.getCommission()) * 0.33);
				price = Double.valueOf(vo.getPrice()) - rebatePrice;
				price = new BigDecimal(price).setScale(2, BigDecimal.ROUND_HALF_UP).doubleValue();     
				rebatePrice = new BigDecimal(rebatePrice).setScale(2, BigDecimal.ROUND_HALF_UP).doubleValue();
			}catch(Exception e){
				logger.error("计算到手价失败", e);
			}
			
			String couponPrice = vo.getCouponPrice() == null ? "0" : vo.getCouponPrice();
			String info =vo.getHasCoupon() ? "领" + couponPrice + "元券，下单返"+rebatePrice.toString() + "元" :  "下单返"+rebatePrice.toString() + "元";
				 
			g.setFont(new Font("Microsoft YaHei", Font.BOLD, 30));
			g.setColor(new Color(255, 255, 255));
			g.drawString(info , vo.getHasCoupon() ? 40 : 110, y+15);

			g.setFont(new Font("Microsoft YaHei", Font.PLAIN, 28));
			g.setColor(new Color(255, 255, 255));
			g.drawString("超值好物，买就返现" , 90, y+65);
			 
			String btnTitle ="长按获取";
			g.setColor(new Color(255, 255, 255));
			g.setFont(new Font("Microsoft YaHei", Font.PLAIN, 32));
			g.drawString(btnTitle, 530, y+25);
				
			y+=88;
		
			// 写入二维码
			String prefix = "jd".equals(vo.getFrom()) ? ZshopConstants.JD_PREFIX : "pdd".equals(vo.getFrom()) ? ZshopConstants.PDD_PREFIX : ZshopConstants.TAOBAO_PREFIX;
			BufferedImage qrcode = QrcodeGenerator.encode(	ZshopConstants.MOBILE_HOST + "/#/detail/" + prefix + vo.getGoodsId(), 230, 230);
			g.drawImage(qrcode, 510, y+5, 230, 230, null);
			
			g.setFont(new Font("Microsoft YaHei", Font.PLAIN, 22));
			g.setColor(Color.gray);
			g.drawString("长按识别二维码" , 550, y+240);
			y+=25;
			
			// 写入平台图片
			g.drawImage(platImage.getScaledInstance(52, 28, Image.SCALE_SMOOTH), 15, y+7, 52, 28, null);
			y+=30;
			
			// 写入商品名
			g.setFont(new Font("Microsoft YaHei", Font.PLAIN, 32));
			g.setColor(Color.BLACK);
			String title = vo.getTitle();
			char[] sc = title.toCharArray();
			int titleOffsetY = 0;
			String titleSub = "";
			int row = 0;
			int j = 0;
			for (int i = 0; i < title.length(); i++) {
				titleSub = title.substring(j, i);
				int titleSubW = g.getFontMetrics().charsWidth(sc, j, i-j);
				int len = row >0 ?  450  : 400;
				if(titleSubW > len){
					j = i;
					int ox = row > 0 ? 15 : 75;
					row++;
					if( row == 3 && j < title.length()-1  ){
						titleSub = titleSub.substring(0, titleSub.length()-1)  + "...";
					}
					g.drawString(titleSub, ox, y + titleOffsetY );
					
					if(row  == 3){
						break;
					}else{
						titleOffsetY += 40;
					}
				}
			}
			if(row == 0){
				titleSub = title.substring(j,  title.length());
				g.drawString(titleSub, 75, y + titleOffsetY );
			}else if(row == 1 || row == 2){
				titleSub = title.substring(j,  title.length());
				g.drawString(titleSub, 10, y + titleOffsetY );
			}
			y =y + titleOffsetY + 40;

			g.setFont(new Font("Microsoft YaHei", Font.PLAIN, 25));
			g.setColor(Color.gray);
			g.drawString("商品价格以实际价格为准", 15, y);
			y+=30;
			
			 // 到手价背景
	        g.drawRect(15, y +10,90,40);
	        g.setColor(new Color(255, 0, 61));
	        g.fillRect(15, y +10,90,40);
	        
			// 到手价
			g.setFont(new Font("Microsoft YaHei", Font.BOLD, 25));
			g.setColor(Color.white);
			g.drawString("到手价" , 23, y+38);
			
			// 到手价人民币图标
			g.setFont(new Font("Microsoft YaHei", Font.PLAIN, 36));
			g.setColor(Color.red);
			g.drawString("¥" , 125, y+45);
			
			// 到手价金额
			g.setFont(new Font("Microsoft YaHei", Font.BOLD, 60));
			g.setColor(Color.red);
			g.drawString(price <0?  vo.getPrice() : price.toString() , 145, y+45);

			// 原价
			g.setFont(new Font("Microsoft YaHei", Font.PLAIN, 30));
			g.setColor(new Color(89, 89, 89));
			g.drawString("原价: " , 350, y+45);

			// 原价金额
			g.setFont(new Font("Microsoft YaHei", Font.PLAIN, 30));
			g.setColor(new Color(89, 89, 89));
			g.drawString("¥" + vo.getOrgPrice() , 415, y+45);
			
			y+=110;
					
			g.setFont(new Font("Microsoft YaHei", Font.PLAIN, 36));
			g.setColor(Color.gray);
			g.drawString("花得值", 110, y);
			
			g.setFont(new Font("Microsoft YaHei", Font.PLAIN, 25));
			g.setColor(Color.gray);
			g.drawString("—— 淘宝、天猫、京东...优惠专享APP", 225, y-5);
			y+=10;
			
			g.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);						// 消除画图锯齿
			g.setRenderingHint(RenderingHints.KEY_TEXT_ANTIALIASING, RenderingHints.VALUE_TEXT_ANTIALIAS_ON);	// 消除文字锯齿

			g.dispose();
			ImageIO.write(bg, "jpg", new File(filePath));
		} catch (IOException e) {
			logger.error("生成优惠券海报失败", e);
		}
	}

注：其中GoodsInfoVO 为商品对象，其中生成二维码的方法可参考另一篇博客 ，地址：https://blog.csdn.net/weixin_38340467/article/details/84784107

核心代码写完之后只要调用一下就好了

@Override
	public String createCouponPoster(String host, Long userId, GoodsInfoVO vo) throws Exception{
		
		String fileUrl = (String)redisUtils.get("couponPoster:u"+userId+"_g"+vo.getGoodsId());
		if(StringUtil.isBlank(fileUrl)){
			//生成图片
			String imagePath = ZshopConstants.UploadFilesConstants.STATICFILESTEMPPATH + System.currentTimeMillis()+".jpg";
			File file = new File(imagePath);
			drawCouponPosterImage(host, userId, vo, imagePath);
			
			//上传至阿里云
			JSONObject res = ossService.sendFile(imagePath);
			if(res.getIntValue(SysCommand.CODE) == 1){
				fileUrl = res.getString("file")+"?x-oss-process=style/w750";
				redisUtils.set("couponPoster:u"+userId+"_g"+vo.getGoodsId(), fileUrl, 0);
			}
			//删除服务器端文件
			file.delete();
		}
		return fileUrl;
	}