1.先下載zxing開發包，這裡用到的只是core那個jar包 

2.使用zxing開發還需要一個類，程式碼如下

package com.sudytech.zxing;

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

import javax.imageio.ImageIO;

import com.google.zxing.BarcodeFormat;
import com.google.zxing.EncodeHintType;
import com.google.zxing.MultiFormatWriter;
import com.google.zxing.common.BitMatrix;

public class TextZXing {
	private static final int BLACK = 0xFF000000;
	private static final int WHITE = 0xFFFFFFFF;

	private TextZXing() {
	}

	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);
		}
	}

	public static void main(String[] args) throws Exception {
		String text = "weixin://wxpay/bizpayurl?appid=wxf8b4f85f3a794e77&noncestr=pyqHJLTwa2H3Vz3k&productid=abc&sign=6f19c6f90ace86f18c906c9ce2a5288e7ed7fd55×tamp=1432796925";
		int width = 300;
		int height = 300;
		// 二維碼的圖片格式
		String format = "jpg";
		Hashtable hints = new Hashtable();
		// 內容所使用編碼
		hints.put(EncodeHintType.CHARACTER_SET, "utf-8");
		BitMatrix bitMatrix = new MultiFormatWriter().encode(text,
				BarcodeFormat.QR_CODE, width, height, hints);
		// 生成二維碼
		File outputFile = new File("F:" + File.separator + "new.png");
		TextZXing.writeToFile(bitMatrix, format, outputFile);
	}
}