java中的二维码(QRcode码)-优快云博客

本文详细介绍了一种使用Java实现的QR码生成及解析的方法。通过具体的代码示例，展示了如何利用Google ZXing库来创建QR码图片并从图片中读取信息。此外，还介绍了在web应用中展示这些QR码的方式。

这里二维码插件用的是QRcode；

用的时候需导入core.jar和javase.jar的jar包;

package test;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.util.Hashtable;

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.LuminanceSource;
import com.google.zxing.MultiFormatReader;
import com.google.zxing.MultiFormatWriter;
import com.google.zxing.Reader;
import com.google.zxing.ReaderException;
import com.google.zxing.Result;
import com.google.zxing.WriterException;
import com.google.zxing.client.j2se.BufferedImageLuminanceSource;
import com.google.zxing.client.j2se.MatrixToImageWriter;
import com.google.zxing.common.BitMatrix;
import com.google.zxing.common.HybridBinarizer;
public class QRcode {
@SuppressWarnings("unchecked")
public static void main(String[] args) throws WriterException {
	
	 QRcode t=new QRcode();  
     //t.encode();  
      t.decode();
	String text="姓名：张三;年龄:25;电话：15188254969;";//二维码内容；
	int width=100;
	int height=100;
	String format="png";
	@SuppressWarnings("rawtypes")
	Hashtable hints=new Hashtable();
	hints.put(EncodeHintType.CHARACTER_SET, "utf-8");
	BitMatrix bitMatrix=new MultiFormatWriter().encode(text, BarcodeFormat.QR_CODE, width, height, hints);
	File outputFile=new File("D:\\Users\\Administrator\\Workspaces\\MyEclipse 10\\strutsLianxi2\\WebRoot\\img\\a.png");
	try {
		MatrixToImageWriter.writeToFile(bitMatrix, format, outputFile);
	} catch (IOException e) {
		e.printStackTrace();
	}

}

@SuppressWarnings("unchecked")
public void decode() {  
    try {  
        @SuppressWarnings("unused")
		Reader reader = new MultiFormatReader();  
        String imgPath = "D:\\Users\\Administrator\\Workspaces\\MyEclipse 10\\strutsLianxi2\\WebRoot\\img\\a.png";  //这里把生成的二维码图片保存在tomcat的路径里面
        File file = new File(imgPath);  
        BufferedImage image;  
        try {  
            image = ImageIO.read(file);  
            if (image == null) {  
                System.out.println("Could not decode image");  
            }  
            LuminanceSource source = new BufferedImageLuminanceSource(image);  
            BinaryBitmap bitmap = new BinaryBitmap(new HybridBinarizer(  
                    source));  
            Result result;  
            @SuppressWarnings("rawtypes")
			Hashtable hints = new Hashtable();  
            hints.put(DecodeHintType.CHARACTER_SET, "utf-8");  
            result = new MultiFormatReader().decode(bitmap, hints);  
            String resultStr = result.getText();  
            System.out.println(resultStr);  

        } catch (IOException ioe) {  
            System.out.println(ioe.toString());  
        } catch (ReaderException re) {  
            System.out.println(re.toString());  
        }  

    } catch (Exception ex) {  

    }  
}  

}

在jsp中显示的时候用img 标签接受；

如：<img src="img/a.png" alr="">

获得tomcat中的路径：

String path = getServletContext().getRealPath("/");
此时得到的路径是到你工程的webRoot目录下,然后你图片的路径就可以写为：
Stiring imgPath = path + "img/a.png";