Java二维码的生成与下载
1.新增Maven项目（spring-boot项目），pom加入如下：
<parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>2.0.2.RELEASE</version> <relativePath /> <!-- lookup parent from repository --> </parent> <properties> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding> <java.version>1.8</java.version> </properties> <dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> <scope>test</scope> </dependency> <!-- jsp --> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-tomcat</artifactId> </dependency> <dependency> <groupId>org.apache.tomcat.embed</groupId> <artifactId>tomcat-embed-jasper</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-devtools</artifactId> <optional>true</optional> </dependency> <!-- https://mvnrepository.com/artifact/com.google.zxing/core --> <dependency> <groupId>com.google.zxing</groupId> <artifactId>core</artifactId> <version>3.3.3</version> </dependency> <!-- https://mvnrepository.com/artifact/com.google.zxing/javase --> <dependency> <groupId>com.google.zxing</groupId> <artifactId>javase</artifactId> <version>3.3.3</version> </dependency> </dependencies> <build> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> </plugin> </plugins> </build>
2，加入如下工具类：
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
import javax.imageio.ImageIO;
import com.google.zxing.BarcodeFormat;
import com.google.zxing.BinaryBitmap;
import com.google.zxing.DecodeHintType;
import com.google.zxing.EncodeHintType;
import com.google.zxing.MultiFormatReader;
import com.google.zxing.MultiFormatWriter;
import com.google.zxing.NotFoundException;
import com.google.zxing.Result;
import com.google.zxing.client.j2se.BufferedImageLuminanceSource;
import com.google.zxing.client.j2se.MatrixToImageConfig;
import com.google.zxing.client.j2se.MatrixToImageWriter;
import com.google.zxing.common.BitMatrix;
import com.google.zxing.common.HybridBinarizer;
import com.google.zxing.qrcode.decoder.ErrorCorrectionLevel;
/**
* ZXing工具类
* @see -----------------------------------------------------------------------------------------------------------------------
* @see 首页--https://code.google.com/p/zxing
* @see 介绍--用于解析多种格式条形码(EAN-13)和二维码(QRCode)的开源Java类库,其提供了多种应用的类库,如javase/jruby/cpp/csharp/android
* @see 说明--下载到的ZXing-2.2.zip是它的源码,我们在JavaSE中使用时需用到其core和javase两部分
* @see 可直接引入它俩的源码到项目中,或将它俩编译为jar再引入,这是我编译好的：http://download.csdn.net/detail/jadyer/6245849
* @see -----------------------------------------------------------------------------------------------------------------------
* @see 经测试:用微信扫描GBK编码的中文二维码时出现乱码,用UTF-8编码时微信可正常识别
* @see 并且MultiFormatWriter.encode()时若传入hints参数来指定UTF-8编码中文时,微信压根就不识别所生成的二维码
* @see 所以这里使用的是这种方式new String(content.getBytes("UTF-8"), "ISO-8859-1")
* @see -----------------------------------------------------------------------------------------------------------------------
* @see 将logo图片加入二维码中间时,需注意以下几点
* @see 1)生成二维码的纠错级别建议采用最高等级H,这样可以增加二维码的正确识别能力(我测试过,不设置级别时,二维码工具无法读取生成的二维码图片)
* @see 2)头像大小最好不要超过二维码本身大小的1/5,而且只能放在正中间部位,这是由于二维码本身结构造成的(你就把它理解成图片水印吧)
* @see 3)在仿照腾讯微信在二维码四周增加装饰框,那么一定要在装饰框和二维码之间留出白边,这是为了二维码可被识别
* @see -----------------------------------------------------------------------------------------------------------------------
* @version v1.0
* @history v1.0-->方法新建,目前仅支持二维码的生成和解析,生成二维码时支持添加logo头像
* @editor Sep 10, 2013 9:32:23 PM
* @create Sep 10, 2013 2:08:16 PM
* @author 玄玉<http://blog.csdn.net/jadyer>
*/
public class ZixingCode {
/**
* 生成二维码
* @param content 二维码内容
* @param charset 编码二维码内容时采用的字符集(传null时默认采用UTF-8编码)
* @param imagePath 二维码图片存放路径(含文件名)
* @param width 生成的二维码图片宽度
* @param height 生成的二维码图片高度
* @param logoPath logo头像存放路径(含文件名,若不加logo则传null即可)
* @return 生成二维码结果(true or false)
*/
public static boolean encodeQRCodeImage(String content, String charset, String imagePath, int width, int height,
String logoPath) {
Map<EncodeHintType, Object> hints = new HashMap<EncodeHintType, Object>();
// 指定编码格式
// hints.put(EncodeHintType.CHARACTER_SET, "UTF-8");
// 指定纠错级别(L--7%,M--15%,Q--25%,H--30%)
hints.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.H);
// 编码内容,编码类型(这里指定为二维码),生成图片宽度,生成图片高度,设置参数
BitMatrix bitMatrix = null;
try {
bitMatrix = new MultiFormatWriter().encode(
new String(content.getBytes(charset == null ? "UTF-8" : charset), "ISO-8859-1"),
BarcodeFormat.QR_CODE, width, height, hints);
} catch (Exception e) {
System.out.println("编码待生成二维码图片的文本时发生异常,堆栈轨迹如下");
e.printStackTrace();
return false;
}
// 生成的二维码图片默认背景为白色,前景为黑色,但是在加入logo图像后会导致logo也变为黑白色,至于是什么原因还没有仔细去读它的源码
// 所以这里对其第一个参数黑色将ZXing默认的前景色0xFF000000稍微改了一下0xFF000001,最终效果也是白色背景黑色前景的二维码,且logo颜色保持原有不变
MatrixToImageConfig config = new MatrixToImageConfig(0xFF000001, 0xFFFFFFFF);
// 这里要显式指定MatrixToImageConfig,否则还会按照默认处理将logo图像也变为黑白色(如果打算加logo的话,反之则不须传MatrixToImageConfig参数)
try {
MatrixToImageWriter.writeToFile(bitMatrix, imagePath.substring(imagePath.lastIndexOf(".") + 1),
new File(imagePath), config);
} catch (IOException e) {
System.out.println("生成二维码图片[" + imagePath + "]时遇到异常,堆栈轨迹如下");
e.printStackTrace();
return false;
}
// 此时二维码图片已经生成了,只不过没有logo头像,所以接下来根据传入的logoPath参数来决定是否加logo头像
if (null == logoPath) {
return true;
} else {
// 如果此时最终生成的二维码不是我们想要的,那么可以扩展MatrixToImageConfig类(反正ZXing提供了源码)
// 扩展时可以重写其writeToFile方法,令其返回toBufferedImage()方法所生成的BufferedImage对象(尽管这种做法未必能解决为题,故需根据实际情景测试)
// 然后替换这里overlapImage()里面的第一行BufferedImage image = ImageIO.read(new
// File(imagePath));
// 即private static void overlapImage(BufferedImage image, String imagePath,
// String logoPath)
try {
// 这里不需要判断logoPath是否指向了一个具体的文件,因为这种情景下overlapImage会抛IO异常
overlapImage(imagePath, logoPath);
return true;
} catch (IOException e) {
System.out.println("为二维码图片[" + imagePath + "]添加logo头像[" + logoPath + "]时遇到异常,堆栈轨迹如下");
e.printStackTrace();
return false;
}
}
}
/**
* 为二维码图片增加logo头像
* @see 其原理类似于图片加水印
* @param imagePath 二维码图片存放路径(含文件名)
* @param logoPath logo头像存放路径(含文件名)
*/
private static void overlapImage(String imagePath, String logoPath) throws IOException {
BufferedImage image = ImageIO.read(new File(imagePath));
int logoWidth = image.getWidth() / 5; // 设置logo图片宽度为二维码图片的五分之一
int logoHeight = image.getHeight() / 5; // 设置logo图片高度为二维码图片的五分之一
int logoX = (image.getWidth() - logoWidth) / 2; // 设置logo图片的位置,这里令其居中
int logoY = (image.getHeight() - logoHeight) / 2; // 设置logo图片的位置,这里令其居中
Graphics2D graphics = image.createGraphics();
graphics.drawImage(ImageIO.read(new File(logoPath)), logoX, logoY, logoWidth, logoHeight, null);
graphics.dispose();
ImageIO.write(image, imagePath.substring(imagePath.lastIndexOf(".") + 1), new File(imagePath));
}
/**
* 解析二维码
* @param imagePath 二维码图片存放路径(含文件名)
* @param charset 解码二维码内容时采用的字符集(传null时默认采用UTF-8编码)
* @return 解析成功后返回二维码文本,否则返回空字符串
*/
public static String decodeQRCodeImage(String imagePath, String charset) {
BufferedImage image = null;
try {
image = ImageIO.read(new File(imagePath));
} catch (IOException e) {
e.printStackTrace();
return "";
}
if (null == image) {
System.out.println("Could not decode QRCodeImage");
return "";
}
BinaryBitmap bitmap = new BinaryBitmap(new HybridBinarizer(new BufferedImageLuminanceSource(image)));
Map<DecodeHintType, String> hints = new HashMap<DecodeHintType, String>();
hints.put(DecodeHintType.CHARACTER_SET, charset == null ? "UTF-8" : charset);
Result result = null;
try {
result = new MultiFormatReader().decode(bitmap, hints);
return result.getText();
} catch (NotFoundException e) {
System.out.println("二维码图片[" + imagePath + "]解析失败,堆栈轨迹如下");
e.printStackTrace();
return "";
}
}
public static void main(String[] args) {
String text ="二维码名片：\n姓名：张三"
+ "\n邮箱：[email protected]";
String imagePath ="D:/二维码.png";
String logoPath = "D:/test.jpg";
ZixingCode.encodeQRCodeImage(text, null, imagePath, 800, 800, logoPath);
String decodeString = decodeQRCodeImage(imagePath, null);
System.out.println(decodeString);
}
}
3.application.yml加入配置：
server:
port: 8800
spring:
mvc:
view:
prefix: /WEB-INF/jsp/
suffix: .jsp4.新建QrcodeController：
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.io.OutputStream;
import javax.imageio.ImageIO;
import javax.imageio.stream.FileImageInputStream;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import com.itmayiedu.util.ZixingCode;
@Controller
public class QrCodeController {
@RequestMapping("/index")
public String index () {
return "index";
}
@RequestMapping("/download")
public void download (HttpServletRequest request, HttpServletResponse response) {
//String url = request.getParameter("pictureUrl");
String url = "D:/二维码.png";
//获取文件
File file = new File(url);
//将图片读成二进制流
FileImageInputStream inputStream = null;
OutputStream outputStream = null;
try {
inputStream = new FileImageInputStream (file);
outputStream = response.getOutputStream();
/*byte b [] = new byte[1024];
int len = -1;
while ((len = inputStream.read(b)) != -1) {
outputStream.write(b, 0, len);
}*/
int streamLength = (int) inputStream.length();
byte[] image = new byte[streamLength ];
inputStream.read(image, 0, streamLength );
response.setHeader("Content-Type", "application/octet-stream");
response.setHeader("Content-Disposition", "attachment;filename=" + "aa.png");
outputStream.write(image);
outputStream.flush();
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
inputStream.close();
outputStream.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
@RequestMapping("/getQrcode")
public void service(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
String text ="二维码名片：\n姓名：王稀\nQQ：851372808"
+ "\n电话：18995699027\n邮箱：[email protected]\n博客：http://blog.csdn.net/qqicq2001";
String imagePath ="D:/二维码.png";
String logoPath = "D:/test.jpg";
ZixingCode.encodeQRCodeImage(text, null, imagePath, 800, 800,logoPath);
BufferedImage image =ImageIO.read(new File(imagePath));
ImageIO.write(image, "JPEG", response.getOutputStream());
}
}
5.新建src/main/webapp，该目录下新建文件夹WEB-INF，然后新建文件夹jsp
在jsp下面新建index.html
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
<a href="download"><img alt="" src="getQrcode"></a>
</body>
</html>6.启动项目，访问：http://127.0.0.1:8800/index即可，点击图片就可以下载