二维码的生成与解析。有多种途径。我选择用大品牌，google老大的zxing。

gitHub链接是(我用的3.0.0，已经是nio了)

https://github.com/zxing/zxing/tree/zxing-3.0.0

Java代码  

1. // 其中输出图像和读取图像的类在core包  
2.   
3. MultiFormatReader  
4.   
5. MultiFormatWriter  
6.   
7. // 生成矩阵的类在javase的包里  
8.   
9. MatrixToImageWriter  

pom.xml中的配置为

Xml代码  

1. <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"  
2.     xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">  
3.     <modelVersion>4.0.0</modelVersion>  
4.   
5.     <groupId>com.shihy</groupId>  
6.     <artifactId>qrcode</artifactId>  
7.     <version>0.0.1-SNAPSHOT</version>  
8.     <packaging>jar</packaging>  
9.   
10.     <name>qrcode</name>  
11.     <url>http://maven.apache.org</url>  
12.   
13.     <properties>  
14.         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>  
15.     </properties>  
16.   
17.     <dependencies>  
18.         <dependency>  
19.             <groupId>com.google.zxing</groupId>  
20.             <artifactId>core</artifactId>  
21.             <version>3.0.0</version>  
22.         </dependency>  
23.         <dependency>  
24.             <groupId>com.google.zxing</groupId>  
25.             <artifactId>javase</artifactId>  
26.             <version>3.0.0</version>  
27.         </dependency>  
28.         <dependency>  
29.             <groupId>junit</groupId>  
30.             <artifactId>junit</artifactId>  
31.             <version>4.10</version>  
32.         </dependency>  
33.         <dependency>  
34.             <groupId>com.alibaba</groupId>  
35.             <artifactId>fastjson</artifactId>  
36.             <version>1.1.29</version>  
37.         </dependency>  
38.     </dependencies>  
39. </project>  

生成图像与解析图像的测试工具类：

Java代码  

1. package com.polysaas.edu.qrcode;  
2.   
3. import java.awt.image.BufferedImage;  
4. import java.io.File;  
5. import java.io.IOException;  
6. import java.nio.file.FileSystems;  
7. import java.nio.file.Path;  
8. import java.util.HashMap;  
9. import java.util.Map;  
10.   
11. import javax.imageio.ImageIO;  
12.   
13. import org.junit.Test;  
14.   
15. import com.alibaba.fastjson.JSONObject;  
16. import com.google.zxing.BarcodeFormat;  
17. import com.google.zxing.Binarizer;  
18. import com.google.zxing.BinaryBitmap;  
19. import com.google.zxing.DecodeHintType;  
20. import com.google.zxing.EncodeHintType;  
21. import com.google.zxing.LuminanceSource;  
22. import com.google.zxing.MultiFormatReader;  
23. import com.google.zxing.MultiFormatWriter;  
24. import com.google.zxing.NotFoundException;  
25. import com.google.zxing.Result;  
26. import com.google.zxing.WriterException;  
27. import com.google.zxing.client.j2se.BufferedImageLuminanceSource;  
28. import com.google.zxing.client.j2se.MatrixToImageWriter;  
29. import com.google.zxing.common.BitMatrix;  
30. import com.google.zxing.common.HybridBinarizer;  
31.   
32. public class QRCodeTest {  
33.   
34.     /** 
35.      * 生成图像 
36.      *  
37.      * @throws WriterException 
38.      * @throws IOException 
39.      */  
40.     @Test  
41.     public void testEncode() throws WriterException, IOException {  
42.         String filePath = "D://";  
43.         String fileName = "zxing.png";  
44.         JSONObject json = new JSONObject();  
45.         json.put(  
46.                 "zxing",  
47.                 "https://github.com/zxing/zxing/tree/zxing-3.0.0/javase/src/main/java/com/google/zxing");  
48.         json.put("author", "shihy");  
49.         String content = json.toJSONString();// 内容  
50.         int width = 200; // 图像宽度  
51.         int height = 200; // 图像高度  
52.         String format = "png";// 图像类型  
53.         Map<EncodeHintType, Object> hints = new HashMap<EncodeHintType, Object>();  
54.         hints.put(EncodeHintType.CHARACTER_SET, "UTF-8");  
55.         BitMatrix bitMatrix = new MultiFormatWriter().encode(content,  
56.                 BarcodeFormat.QR_CODE, width, height, hints);// 生成矩阵  
57.         Path path = FileSystems.getDefault().getPath(filePath, fileName);  
58.         MatrixToImageWriter.writeToPath(bitMatrix, format, path);// 输出图像  
59.         System.out.println("输出成功.");  
60.     }  
61.   
62.     /** 
63.      * 解析图像 
64.      */  
65.     @Test  
66.     public void testDecode() {  
67.         String filePath = "D://zxing.png";  
68.         BufferedImage image;  
69.         try {  
70.             image = ImageIO.read(new File(filePath));  
71.             LuminanceSource source = new BufferedImageLuminanceSource(image);  
72.             Binarizer binarizer = new HybridBinarizer(source);  
73.             BinaryBitmap binaryBitmap = new BinaryBitmap(binarizer);  
74.             Map<DecodeHintType, Object> hints = new HashMap<DecodeHintType, Object>();  
75.             hints.put(DecodeHintType.CHARACTER_SET, "UTF-8");  
76.             Result result = new MultiFormatReader().decode(binaryBitmap, hints);// 对图像进行解码  
77.             JSONObject content = JSONObject.parseObject(result.getText());  
78.             System.out.println("图片中内容：  ");  
79.             System.out.println("author： " + content.getString("author"));  
80.             System.out.println("zxing：  " + content.getString("zxing"));  
81.             System.out.println("图片中格式：  ");  
82.             System.out.println("encode： " + result.getBarcodeFormat());  
83.         } catch (IOException e) {  
84.             e.printStackTrace();  
85.         } catch (NotFoundException e) {  
86.             e.printStackTrace();  
87.         }  
88.     }  
89. }  

测试生成图像为：

解析到的内容为：

Java代码  

1. 图片中内容：    
2. author： shihy  
3. zxing：  https://github.com/zxing/zxing/tree/zxing-3.0.0/javase/src/main/java/com/google/zxing  
4. 图片中格式：    
5. encode： QR_CODE