package com.stylefeng.guns.modular.system.controller.util;
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import com.google.zxing.BarcodeFormat;
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import com.google.zxing.EncodeHintType;
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import com.google.zxing.MultiFormatWriter;
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import com.google.zxing.WriterException;
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import com.google.zxing.common.BitMatrix;
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import com.google.zxing.qrcode.decoder.ErrorCorrectionLevel;
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import org.springframework.util.StringUtils;
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import javax.imageio.ImageIO;
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import java.awt.image.BufferedImage;
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import java.io.OutputStream;
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import java.util.HashMap;
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import java.util.Map;
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public class MyQrCodeUtil {
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//CODE_WIDTH：二维码宽度，单位像素
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private static final int CODE_WIDTH = 400;
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//CODE_HEIGHT：二维码高度，单位像素
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private static final int CODE_HEIGHT = 400;
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//FRONT_COLOR：二维码前景色，0x000000 表示黑色
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private static final int FRONT_COLOR = 0x000000;
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//BACKGROUND_COLOR：二维码背景色，0xFFFFFF 表示白色
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//演示用 16 进制表示，和前端页面 CSS 的取色是一样的，注意前后景颜色应该对比明显，如常见的黑白
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private static final int BACKGROUND_COLOR = 0xFFFFFF;
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public static BufferedImage createCodeToFile(String content) {
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try {
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content = content.trim();
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//核心代码-生成二维码
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BufferedImage bufferedImage = getBufferedImage(content);
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return bufferedImage;
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} catch (Exception e) {
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e.printStackTrace();
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}
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return null;
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}
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/**
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* 生成二维码并输出到输出流, 通常用于输出到网页上进行显示，输出到网页与输出到磁盘上的文件中，区别在于最后一句 ImageIO.write
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* write(RenderedImage im,String formatName,File output)：写到文件中
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* write(RenderedImage im,String formatName,OutputStream output)：输出到输出流中
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* @param content ：二维码内容
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* @param outputStream ：输出流，比如 HttpServletResponse 的 getOutputStream
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*/
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public static void createCodeToOutputStream(String content, OutputStream outputStream) {
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try {
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if (!StringUtils.hasLength(content)) {
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return;
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}
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content = content.trim();
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//核心代码-生成二维码
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BufferedImage bufferedImage = getBufferedImage(content);
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//区别就是这一句，输出到输出流中，如果第三个参数是 File，则输出到文件中
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ImageIO.write(bufferedImage, "png", outputStream);
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System.out.println("二维码图片生成到输出流成功...");
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} catch (Exception e) {
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e.printStackTrace();
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}
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}
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//核心代码-生成二维码
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private static BufferedImage getBufferedImage(String content) throws WriterException {
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//com.google.zxing.EncodeHintType：编码提示类型,枚举类型
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Map<EncodeHintType, Object> hints = new HashMap();
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//EncodeHintType.CHARACTER_SET：设置字符编码类型
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hints.put(EncodeHintType.CHARACTER_SET, "UTF-8");
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//EncodeHintType.ERROR_CORRECTION：设置误差校正
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//ErrorCorrectionLevel：误差校正等级，L = ~7% correction、M = ~15% correction、Q = ~25% correction、H = ~30% correction
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//不设置时，默认为 L 等级，等级不一样，生成的图案不同，但扫描的结果是一样的
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hints.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.M);
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//EncodeHintType.MARGIN：设置二维码边距，单位像素，值越小，二维码距离四周越近
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hints.put(EncodeHintType.MARGIN, 1);
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MultiFormatWriter multiFormatWriter = new MultiFormatWriter();
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BitMatrix bitMatrix = multiFormatWriter.encode(content, BarcodeFormat.QR_CODE, CODE_WIDTH, CODE_HEIGHT, hints);
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BufferedImage bufferedImage = new BufferedImage(CODE_WIDTH, CODE_HEIGHT, BufferedImage.TYPE_INT_BGR);
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for (int x = 0; x < CODE_WIDTH; x++) {
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for (int y = 0; y < CODE_HEIGHT; y++) {
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bufferedImage.setRGB(x, y, bitMatrix.get(x, y) ? FRONT_COLOR : BACKGROUND_COLOR);
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}
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}
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return bufferedImage;
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}
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public static void main(String[] args) {
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String param = "{\n" +
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" \"scan_type\": 1,\n" +
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" \"space_id\": 2,\n" +
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" \"sutu_id\": 3\n" +
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"}";
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createCodeToFile(param);
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}
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}
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