Java利用Zxing生成二维码

Maven 依赖

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<dependency>  
<groupId>com.google.zxing</groupId>
<artifactId>core</artifactId>
<version>2.0</version>
</dependency>

二维码的生成

  • 利用Maven将Zxing-core.jar 包加入到项目中。
  • 二维码的生成需要借助MatrixToImageWriter类,该类是由Google提供的,可以将该类拷贝到源码中,这里我将该类的源码贴上,可以直接使用。
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import com.google.zxing.common.BitMatrix;  
import javax.imageio.ImageIO;
import java.io.File;
import java.io.OutputStream;
import java.io.IOException;
import java.awt.image.BufferedImage;


public final class MatrixToImageWriter {

private static final int BLACK = 0xFF000000;
private static final int WHITE = 0xFFFFFFFF;

private MatrixToImageWriter() {}


public static BufferedImage toBufferedImage(BitMatrix matrix) {
int width = matrix.getWidth();
int height = matrix.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, matrix.get(x, y) ? BLACK : WHITE);
}
}
return image;
}


public static void writeToFile(BitMatrix matrix, String format, File file)
throws IOException {
BufferedImage image = toBufferedImage(matrix);
if (!ImageIO.write(image, format, file)) {
throw new IOException("Could not write an image of format " + format + " to " + file);
}
}


public static void writeToStream(BitMatrix matrix, String format, OutputStream stream)
throws IOException {
BufferedImage image = toBufferedImage(matrix);
if (!ImageIO.write(image, format, stream)) {
throw new IOException("Could not write an image of format " + format);
}
}

}

编写生成二维码的实现代码

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try {  

String content = "http://www.baidu.com";
String path = "C:/Users/Administrator/Desktop/testImage";

MultiFormatWriter multiFormatWriter = new MultiFormatWriter();

Map hints = new HashMap();
hints.put(EncodeHintType.CHARACTER_SET, "UTF-8");
BitMatrix bitMatrix = multiFormatWriter.encode(content, BarcodeFormat.QR_CODE, 400, 400,hints);
File file1 = new File(path,"测试打开百度.jpg");
MatrixToImageWriter.writeToFile(bitMatrix, "jpg", file1);

} catch (Exception e) {
e.printStackTrace();
}

现在运行后即可生成一张二维码图片

二维码的解析

  • 利用Maven将Zxing-core.jar 包加入到项目中。
  • 和生成一样,我们需要一个辅助类( BufferedImageLuminanceSource),同样该类Google也提供了,这里我同样将该类的源码贴出来,可以直接拷贝使用个,省去查找的麻烦
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BufferedImageLuminanceSource   
import com.google.zxing.LuminanceSource;

import java.awt.Graphics2D;
import java.awt.geom.AffineTransform;
import java.awt.image.BufferedImage;

public final class BufferedImageLuminanceSource extends LuminanceSource {

private final BufferedImage image;
private final int left;
private final int top;

public BufferedImageLuminanceSource(BufferedImage image) {
this(image, 0, 0, image.getWidth(), image.getHeight());
}

public BufferedImageLuminanceSource(BufferedImage image, int left, int top, int width, int height) {
super(width, height);

int sourceWidth = image.getWidth();
int sourceHeight = image.getHeight();
if (left + width > sourceWidth || top + height > sourceHeight) {
throw new IllegalArgumentException("Crop rectangle does not fit within image data.");
}

for (int y = top; y < top + height; y++) {
for (int x = left; x < left + width; x++) {
if ((image.getRGB(x, y) & 0xFF000000) == 0) {
image.setRGB(x, y, 0xFFFFFFFF); // = white
}
}
}

this.image = new BufferedImage(sourceWidth, sourceHeight, BufferedImage.TYPE_BYTE_GRAY);
this.image.getGraphics().drawImage(image, 0, 0, null);
this.left = left;
this.top = top;
}

@Override
public byte[] getRow(int y, byte[] row) {
if (y < 0 || y >= getHeight()) {
throw new IllegalArgumentException("Requested row is outside the image: " + y);
}
int width = getWidth();
if (row == null || row.length < width) {
row = new byte[width];
}
image.getRaster().getDataElements(left, top + y, width, 1, row);
return row;
}

@Override
public byte[] getMatrix() {
int width = getWidth();
int height = getHeight();
int area = width * height;
byte[] matrix = new byte[area];
image.getRaster().getDataElements(left, top, width, height, matrix);
return matrix;
}

@Override
public boolean isCropSupported() {
return true;
}

@Override
public LuminanceSource crop(int left, int top, int width, int height) {
return new BufferedImageLuminanceSource(image, this.left + left, this.top + top, width, height);
}

@Override
public boolean isRotateSupported() {
return true;
}

@Override
public LuminanceSource rotateCounterClockwise() {

int sourceWidth = image.getWidth();
int sourceHeight = image.getHeight();

AffineTransform transform = new AffineTransform(0.0, -1.0, 1.0, 0.0, 0.0, sourceWidth);

BufferedImage rotatedImage = new BufferedImage(sourceHeight, sourceWidth, BufferedImage.TYPE_BYTE_GRAY);

Graphics2D g = rotatedImage.createGraphics();
g.drawImage(image, transform, null);
g.dispose();

int width = getWidth();
return new BufferedImageLuminanceSource(rotatedImage, top, sourceWidth - (left + width), getHeight(), width);
}

}

编写解析二维码的实现代码

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try {  
MultiFormatReader formatReader = new MultiFormatReader();
String filePath = "C:/Users/Administrator/Desktop/testImage/test.jpg";
File file = new File(filePath);
BufferedImage image = ImageIO.read(file);;
LuminanceSource source = new BufferedImageLuminanceSource(image);
Binarizer binarizer = new HybridBinarizer(source);
BinaryBitmap binaryBitmap = new BinaryBitmap(binarizer);
Map hints = new HashMap();
hints.put(EncodeHintType.CHARACTER_SET, "UTF-8");
Result result = formatReader.decode(binaryBitmap,hints);

System.out.println("result = "+ result.toString());
System.out.println("resultFormat = "+ result.getBarcodeFormat());
System.out.println("resultText = "+ result.getText());

} catch (Exception e) {
e.printStackTrace();
}

现在运行后可以看到控制台打印出了二维码的内容

hibernate-configuration

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<hibernate-configuration>
<session-factory>
<propertyname="connection.driver_class">com.mysql.jdbc.Driver</property>
<propertyname="connection.url">jdbc:mysql://localhost:3306/hibernate-1</property>
<propertyname="connection.username">root</property>
<propertyname="connection.password">root</property>
<property name="dialect">org.hibernate.dialect.MySQLDialect</property>
<propertyname="show_sql">true</property>
<propertyname="format_sql">true</property>
<propertyname="hbm2ddl.auto">create</property>
<mappingresource="com/yuan/model/Customer.hbm.xml"/>
</session-factory>
</hibernate-configuration>

hibernate级联操作

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<many-to-one name="category" class="Category" cascade="save-update">
<!-- 映射的字段 -->
<column name="categoryId"/>
</many-to-one>
cascade
none;//默认
save-update;
delete;
all;

Hibernate关系映射

多对一单向映射 –> hibernate=-4

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 <many-to-onename="category"class="com.yuan.hibernate.Category"fetch="join">
<columnname="CATEGORYID"/>
</many-to-one>
privateCategorycategory;

多对一双向映射 –> hibernate-5

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<many-to-onename="category"class="com.yuan.hibernate.Category"fetch="join">
<columnname="CATEGORY"/>
</many-to-one>

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  <setname="book"table="BOOK"inverse="false"lazy="true">
<key>
<columnname="ID"/>
</key>
<one-to-manyclass="com.yuan.hibernate.Book"/>
</set>
privateSet<Book>book;

一对一主键关系映射 –> hibernate-6

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<one-to-onename="user"class="com.yuan.model.User"></one-to-one>
<one-to-onename="idCard"class="com.yuan.model.IdCard"></one-to-one>
privateUseruser;
privateIdCardidCard;

一对一主键外键关系映射 – > hibernate-7

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<many-to-onename="idCard"update="true"/>
privateIdCardidCard;

多对多关系映射 – > hibernate-8

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<setname="students"table="STUDENT_COURSE"inverse="false"lazy="true">
<key>
<columnname="COURSEID"/>
</key>
<many-to-manyclass="com.yuan.model.Student"column="STUDENTID"/>
</set>
```







privateSetstudents;
privateSetcourses;
```

HibernateUtil.save

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Sessionsession=null;
try{
session=HibernateUtil.getSession();
session.beginTransaction();
session.save(customer);
session.getTransaction().commit();
}catch(Exceptione){
e.printStackTrace();
session.getTransaction().rollback();
}finally{
HibernateUtil.closeSession();
}

HibernateUtil

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package com.yuan.hibernate;

import org.hibernate.HibernateException;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;
import org.hibernate.service.ServiceRegistryBuilder;

public class HibernateUtil {
private static final ThreadLocal<Session> threadLocal = new ThreadLocal<Session>();
private static SessionFactory sessionFactory = null; // SessionFactory对象
// 静态块
static {
try {
Configuration cfg = new Configuration().configure(); // 加载Hibernate配置文件
sessionFactory = cfg
.buildSessionFactory(new ServiceRegistryBuilder().applySettings(cfg.getProperties())
.buildServiceRegistry());
} catch (Exception e) {
System.err.println("创建会话工厂失败");
e.printStackTrace();
}
}

/**
* 获取Session
*
* @return Session
* @throws HibernateException
*/
public static Session getSession() throws HibernateException {
Session session = (Session) threadLocal.get();
if (session == null || !session.isOpen()) {
if (sessionFactory == null) {
rebuildSessionFactory();
}
session = (sessionFactory != null) ? sessionFactory.openSession()
: null;
threadLocal.set(session);
}
return session;
}

/**
* 重建会话工厂
*/
public static void rebuildSessionFactory() {
try {
Configuration cfg = new Configuration().configure(); // 加载Hibernate配置文件
sessionFactory = cfg
.buildSessionFactory(new ServiceRegistryBuilder().applySettings(cfg.getProperties())
.buildServiceRegistry());
} catch (Exception e) {
System.err.println("创建会话工厂失败");
e.printStackTrace();
}
}

/**
* 获取SessionFactory对象
*
* @return SessionFactory对象
*/
public static SessionFactory getSessionFactory() {
return sessionFactory;
}

/**
* 关闭Session
*
* @throws HibernateException
*/
public static void closeSession() throws HibernateException {
Session session = (Session) threadLocal.get();
threadLocal.set(null);
if (session != null) {
session.close(); // 关闭Session
}
}
}