1-1. ZXing是一个开源Java类库用于解析多种格式的条形码和二维码.

官网：http://code.google.com/p/zxing/

提供以下编码格式的支持：

• UPC-A and UPC-E
• EAN-8 and EAN-13
• Code 39
• Code 93
• Code 128
• QR Code
• ITF
• Codabar
• RSS-14 (all variants)
• Data Matrix
• PDF 417 ('alpha' quality)
• Aztec ('alpha' quality)

同时官网提供了 Android、cpp、C#、iPhone、j2me、j2se、jruby、objc、rim、symbian等多种应用的类库，具体详情可以参考下载的源码包中。

可以将文档中core、javase文件夹中的源码打包成jar供如下使用：

package org.hz.recode;

import java.awt.image.BufferedImage;
import java.io.File;
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.Result;
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;
import com.google.zxing.qrcode.decoder.ErrorCorrectionLevel;

public class ZxingHandler {
	/** 
     * 编码 
     * @param contents 
     * @param width 
     * @param height 
     * @param imgPath 
     */  
    public void encode(String contents, int width, int height, String imgPath) {  
        Hashtable<Object, Object> hints = new Hashtable<Object, Object>();  
        // 指定纠错等级  
        hints.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.L);  
        // 指定编码格式  
        hints.put(EncodeHintType.CHARACTER_SET, "GBK");  
        try {  
            BitMatrix bitMatrix = new MultiFormatWriter().encode(contents,  
                    BarcodeFormat.QR_CODE, width, height, hints);  
  
            MatrixToImageWriter  
                    .writeToFile(bitMatrix, "png", new File(imgPath));  
  
        } catch (Exception e) {  
            e.printStackTrace();  
        }  
    }
    
    /** 
     * @param imgPath 
     * @return String 
     */  
    public String decode(String imgPath) {  
        BufferedImage image = null;  
        Result result = null;  
        try {  
            image = ImageIO.read(new File(imgPath));  
            if (image == null) {  
                System.out.println("the decode image may be not exit.");  
            }  
            LuminanceSource source = new BufferedImageLuminanceSource(image);  
            BinaryBitmap bitmap = new BinaryBitmap(new HybridBinarizer(source));  
  
            Hashtable<Object, Object> hints = new Hashtable<Object, Object>();  
            hints.put(DecodeHintType.CHARACTER_SET, "GBK");  
  
            result = new MultiFormatReader().decode(bitmap, hints);  
            return result.getText();  
        } catch (Exception e) {  
            e.printStackTrace();  
        }  
        return null;  
    }  
  
    /** 
     * @param args 
     */  
    public static void main(String[] args) {  
		String imgPath = "d:/michael_zxing.png";
		String contents = "Hi! welcome to Zxing!";  
		int width = 300, height = 300;
		ZxingHandler encodeHandler = new ZxingHandler();
		encodeHandler.encode(contents, width, height, imgPath);
    	
        ZxingHandler decodeDandler = new ZxingHandler();  
        String decodeContent = decodeDandler.decode(imgPath);  
        System.out.println("解码内容如下：");  
        System.out.println(decodeContent);  
    }  
}