JAVA生成图形验证码或图片的draw方式

第一步， 生成本地图片 再进行操作，经常用于图片验证码，或者加水印，加盖章之类

 public void drawImage() throws FileNotFoundException, IOException {
        int width = 350;
        int height = 450;
        int fontSize = 20;
        Prescription prescriptionResult = prescriptionRepository.getById(837982537646080L);
        File file = new File("D:/draw/java-draw.jpg");
        //   //字体大小   Font.PLAIN,  Font.BOLD
        Font font = new Font("Serif", Font.BOLD, fontSize);
        BufferedImage bi = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
        Graphics2D g2 = (Graphics2D) bi.getGraphics();
        g2.setBackground(Color.WHITE);
        // g2.clearRect(0, 0, width, height);
        // 背景色填充，这里设置为全部
        g2.fillRect(0, 0, width, height);
        g2.setFont(font);

        List<String> list = new ArrayList();
        list.add("药品名称: " + prescriptionResult.getDrugName());
        list.add(
            "总数量: " + prescriptionResult.getQuantity() + "(" + prescriptionResult.getUnit() + ")");
        list.add("用法: " + prescriptionResult.getUseage());
        list.add(
            "单次剂量: " + prescriptionResult.getSingle() + "(" + prescriptionResult.getSingleUnit()
                + ")");
        list.add("用药频次: " + prescriptionResult.getUseFrequency());
        list.add("疗程: " + prescriptionResult.getCourseTreatment());

        double median = list.size() / 2.0 + 0.5;
        int rowSpacing = 30;
        for (int i = 0; i < list.size(); i++) {
            g2.setPaint(Color.black);
            String text = list.get(i);
            FontDesignMetrics metrics = FontDesignMetrics.getMetrics(font);
            int strWidth = metrics.stringWidth(text);
            int strHeight = metrics.getHeight();
            //左边位置
            int left = (width - strWidth) / 2;
            // 顶边位置+上升距离（原本字体基线位置对准画布的y坐标导致字体偏上ascent距离，加上ascent后下移刚好顶边吻合）
            int top = (height - strHeight) / 2 + metrics.getAscent();
            top = (int) (top + (Double.parseDouble(String.valueOf(i + 1)) - median) * fontSize);
            g2.drawString(text, left, top);

        }
        ImageIO.write(bi, "jpg", file);
    }

2 下面是换行的参考方法，叠加有些坐标问题需要调试

 //drawText(g2, text, 500, font, 100, 0, rowSpacing, Color.black, Color.black);
    static void drawText(Graphics2D g, String text, int srcImgWidth, Font font, int beginX,
                         int beginY, int rowSpacing, Color backGroundColor, Color fontColor) {
        if (backGroundColor != null) {
            g.setColor(backGroundColor);
            g.fillRect(beginX - 40, beginY - 5, font.getSize() * 4 + 50 * 2,
                font.getSize() + 15 * 2);
        }
        if (fontColor != null) {
            g.setColor(fontColor);
        } else {
            g.setColor(Color.black);
        }
        g.setFont(font);
        int fontSize = font.getSize();
        //文字叠加,自动换行叠加
        int tempX = beginX + 2;
        int tempY = beginY + fontSize;
        int tempCharLen = 0;//单字符长度
        int tempLineLen = 0;//单行字符总长度临时计算
        StringBuffer sb = new StringBuffer();
        int textMaxWidth = srcImgWidth - 10;

        for (int i = 0; i < text.length(); i++) {
            char tempChar = text.charAt(i);
            tempCharLen = getCharLen(tempChar, g);
            tempLineLen += tempCharLen;
            if (tempLineLen >= textMaxWidth) {
                //长度已经满一行,进行文字叠加
                g.drawString(sb.toString(), tempX, tempY);
                sb.delete(0, sb.length());//清空内容,重新追加
                tempY += (fontSize + rowSpacing);
                tempLineLen = 0;
            }
            sb.append(tempChar);//追加字符
        }
        g.drawString(sb.toString(), tempX, tempY);//最后叠加余下的文字
    }

    public static int getCharLen(char c, Graphics2D g) {
        return g.getFontMetrics(g.getFont()).charWidth(c);

    }

本文地址：https://blog.csdn.net/limingcai168/article/details/108236058