java练习：二维码生成和输出

<!--二维码生成-->
<dependency>
    <groupId>com.google.zxing</groupId>
    <artifactId>core</artifactId>
    <version>2.2</version>
</dependency>
<dependency>
    <groupId>com.google.zxing</groupId>
    <artifactId>javase</artifactId>
    <version>2.2</version>
</dependency>

package com.example.myblog.util;
import com.google.zxing.BarcodeFormat;
import com.google.zxing.EncodeHintType;
import com.google.zxing.MultiFormatWriter;
import com.google.zxing.WriterException;
import com.google.zxing.common.BitMatrix;
import com.google.zxing.qrcode.decoder.ErrorCorrectionLevel;

import java.awt.image.BufferedImage;
import java.util.Hashtable;

public class QRCodeUtil {

    private static final String CHARSET = "utf-8";

    // 二维码尺寸
    private static final int QRCODE_SIZE = 300;

    public static BufferedImage createImage(String content) {
        Hashtable<EncodeHintType, Object> hints = new Hashtable<EncodeHintType, Object>();
        hints.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.H);
        hints.put(EncodeHintType.CHARACTER_SET, CHARSET);
        hints.put(EncodeHintType.MARGIN, 1);
        BitMatrix bitMatrix = null;
        try {
            bitMatrix = new MultiFormatWriter().encode(content, BarcodeFormat.QR_CODE, QRCODE_SIZE, QRCODE_SIZE,
                    hints);
        } catch (WriterException e) {
            e.printStackTrace();
        }
        int width = bitMatrix.getWidth();
        int height = bitMatrix.getHeight();
        BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
        for (int x = 0; x < width; x++) {
            for (int y = 0; y < height; y++) {
                image.setRGB(x, y, bitMatrix.get(x, y) ? 0xFF000000 : 0xFFFFFFFF);
            }
        }
        return image;
    }
}

package com.example.myblog.api;

import com.example.myblog.util.QRCodeUtil;
import com.google.zxing.BarcodeFormat;
import com.google.zxing.EncodeHintType;
import com.google.zxing.MultiFormatWriter;
import com.google.zxing.WriterException;
import com.google.zxing.common.BitMatrix;
import com.google.zxing.qrcode.decoder.ErrorCorrectionLevel;
import io.swagger.annotations.ApiParam;
import org.springframework.web.bind.annotation.*;

import javax.imageio.ImageIO;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletResponse;
import java.awt.*;
import java.awt.geom.RoundRectangle2D;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.util.Hashtable;
import java.util.UUID;

/**
 * @author wyk on 2018/10/27
 */
@RestController
@RequestMapping("/qrcode")
public class QRCodeApi {

    private static final String CHARSET = "utf-8";

    // 二维码尺寸
    private static final int QRCODE_SIZE = 300;
    // LOGO宽度
    private static final int LOGO_WIDTH = 80;
    // LOGO高度
    private static final int LOGO_HEIGHT = 80;

    @RequestMapping(value = "/creatImg/{content}",method = RequestMethod.GET)
    public BufferedImage createImage(
            @PathVariable String content
    ) {
        System.out.println(content);
        Hashtable<EncodeHintType, Object> hints = new Hashtable<EncodeHintType, Object>();
        hints.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.H);
        hints.put(EncodeHintType.CHARACTER_SET, CHARSET);
        hints.put(EncodeHintType.MARGIN, 1);
        BitMatrix bitMatrix = null;
        try {
            bitMatrix = new MultiFormatWriter().encode(content, BarcodeFormat.QR_CODE, QRCODE_SIZE, QRCODE_SIZE,
                    hints);
        } catch (WriterException e) {
            e.printStackTrace();
        }
        int width = bitMatrix.getWidth();
        int height = bitMatrix.getHeight();
        BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
        for (int x = 0; x < width; x++) {
            for (int y = 0; y < height; y++) {
                image.setRGB(x, y, bitMatrix.get(x, y) ? 0xFF000000 : 0xFFFFFFFF);
            }
        }
        return image;
    }


    /**
     * 插入LOGO
     *
     * @param source       二维码图片
     * @param logoPath     LOGO图片地址
     * @param needCompress 是否压缩
     * @throws Exception
     */
    public static void insertImage(BufferedImage source, InputStream logoPath, boolean needCompress)  {
        Image src = null;
        try {
            src = ImageIO.read(logoPath);
        } catch (IOException e) {
            e.printStackTrace();
        }
        int width = src.getWidth(null);
        int height = src.getHeight(null);
        if (needCompress) {
            // 压缩LOGO
            if (width > LOGO_WIDTH) {
                width = LOGO_WIDTH;
            }
            if (height > LOGO_HEIGHT) {
                height = LOGO_HEIGHT;
            }
            Image image = src.getScaledInstance(width, height, Image.SCALE_SMOOTH);
            BufferedImage tag = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
            Graphics g = tag.getGraphics();
            // 绘制缩小后的图
            g.drawImage(image, 0, 0, null);
            g.dispose();
            src = image;
        }
        // 插入LOGO
        Graphics2D graph = source.createGraphics();
        int x = (QRCODE_SIZE - width) / 2;
        int y = (QRCODE_SIZE - height) / 2;
        graph.drawImage(src, x, y, width, height, null);
        Shape shape = new RoundRectangle2D.Float(x, y, width, width, 12, 12);
        graph.setStroke(new BasicStroke(3f));
        graph.draw(shape);
        graph.dispose();
    }


    @RequestMapping("/generate")
    @ResponseBody
    public void generateQR(@RequestParam("content") String content, HttpServletResponse response){
        BufferedImage image;
        // 禁止图像缓存
        response.setHeader("Pragma", "No-cache");
        response.setHeader("Cache-Control", "no-cache");
        response.setDateHeader("Expires", 0);
        response.setContentType("image/jpeg");
        image = QRCodeUtil.createImage(content);
        // 创建二进制的输出流
        try(ServletOutputStream sos = response.getOutputStream()){
            // 将图像输出到Servlet输出流中。
            ImageIO.write(image, "jpeg", sos);
        } catch (IOException e) {
            e.printStackTrace();
        }

    }

    // 输出为二维码图片
    @RequestMapping(value = "/generate/{content}",method = RequestMethod.GET)
    public void generate(
            @PathVariable String content, HttpServletResponse response
    ){
        BufferedImage image;
        // 禁止图像缓存
        response.setHeader("Pragma", "No-cache");
        response.setHeader("Cache-Control", "no-cache");
        response.setDateHeader("Expires", 0);
        response.setContentType("image/jpeg");
        image = QRCodeUtil.createImage(content);
        // 创建二进制的输出流
        try(ServletOutputStream sos = response.getOutputStream()){
            // 将图像输出到Servlet输出流中。
            ImageIO.write(image, "jpeg", sos);
        } catch (IOException e) {
            e.printStackTrace();
        }

    }
    // 保存为一个文件
    @RequestMapping(value = "/generate2/{content}",method = RequestMethod.GET)
    public String generate2(
            @PathVariable String content, HttpServletResponse response
    ){
        BufferedImage image;
        // 禁止图像缓存
        response.setHeader("Pragma", "No-cache");
        response.setHeader("Cache-Control", "no-cache");
        response.setDateHeader("Expires", 0);
        response.setContentType("image/jpeg");
        image = QRCodeUtil.createImage(content);
        String fileName = String.valueOf(UUID.randomUUID()).replaceAll("-","");
        String path = "D:\\dataa\\ceshi\\"+fileName+".jpeg";
        try{

            File file = new File(path);
            ImageIO.write(image,"jpeg",file);
        }catch (IOException e){
            e.printStackTrace();
        }
        return path;

    }

}