本人语言组织能力较弱，直接上代码加注释。
1、基本方法
二维码容错率，分四个等级：H、L 、M、 Q
ErrorCorrectionLevel level = ErrorCorrectionLevel.H;
String qrName = "test.png"; //生成二维码图片名称
String targetPath = ServletActionContext.getServletContext().getRealPath("/"); //不解释
File target = new File(targetPath, qrName);
if(!target.exists()){
target.mkdirs();
}
//生成二维码中的设置
Hashtable hints = new Hashtable();
hints.put(EncodeHintType.CHARACTER_SET, "utf-8"); //编码
hints.put(EncodeHintType.ERROR_CORRECTION, level); //容错率
hints.put(EncodeHintType.MARGIN, 0); //二维码边框宽度，这里文档说设置0-4，但是设置后没有效果，不知原因，
String content = “二维码内容”;
int size = 200; //二维码图片大小
BitMatrix bitMatrix = new MultiFormatWriter().encode(content, BarcodeFormat.QR_CODE, size, size,hints); //生成bitMatrix
int margin = 5; //自定义白边边框宽度
bitMatrix = updateBit(bitMatrix, margin); //生成新的bitMatrix
//因为二维码生成时，白边无法控制，去掉原有的白边，再添加自定义白边后，二维码大小与size大小就存在差异了，为了让新
生成的二维码大小还是size大小，根据size重新生成图片
BufferedImage bi = MatrixToImageWriter.toBufferedImage(bitMatrix);
bi = zoomInImage(bi,size,size);//根据size放大、缩小生成的二维码
ImageIO.write(bi, "png", target); //生成二维码图片
这样生成的二维码在图片属性上跟我们设置的图片大小size是一致的。
唯一不明白的就是zxing库中生成二维码是设置白边边框不起作用，如果起作用，就不用这么麻烦了。
2、调用的方法
因为二维码边框设置那里不起作用，不管设置多少，都会生成白边，所以根据网上的例子进行修改，自定义控制白边宽度，
该方法生成自定义白边框后的bitMatrix；
private BitMatrix updateBit(BitMatrix matrix, int margin){
int tempM = margin*2;
int[] rec = matrix.getEnclosingRectangle(); //获取二维码图案的属性
int resWidth = rec[2] + tempM;
int resHeight = rec[3] + tempM;
BitMatrix resMatrix = new BitMatrix(resWidth, resHeight); // 按照自定义边框生成新的BitMatrix
resMatrix.clear();
for(int i= margin; i < resWidth- margin; i++){ //循环，将二维码图案绘制到新的bitMatrix中
for(int j=margin; j < resHeight-margin; j++){
if(matrix.get(i-margin + rec[0], j-margin + rec[1])){
resMatrix.set(i,j);
}
}
}
return resMatrix;
}
/**
* 图片放大缩小
*/
public static BufferedImage zoomInImage(BufferedImage originalImage, int width, int height){
BufferedImage newImage = new BufferedImage(width,height,originalImage.getType());
Graphics g = newImage.getGraphics();
g.drawImage(originalImage, 0,0,width,height,null);
g.dispose();
return newImage;
}
另外二维码的几种生成方法 :
需要引入的包,这里使用的是google的生成方法
import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.io.OutputStream;
import java.util.HashMap;
import java.util.Map;
import javax.imageio.ImageIO;
import javax.servlet.http.HttpServletResponse;
import com.google.zxing.BarcodeFormat;
import com.google.zxing.EncodeHintType;
import com.google.zxing.MultiFormatWriter;
import com.google.zxing.WriterException;
import com.google.zxing.common.BitMatrix;
import com.google.zxing.qrcode.decoder.ErrorCorrectionLevel;
/**
* 二维码工具类 需要zxingcore-2.2.jar
*
* @author Camey
*
*/
public final class QRcodeKit {
private static final int BLACK = 0xFF000000;
private static final int WHITE = 0xFFFFFFFF;
/**
* 生成二维码
*
* @param contents
* 文本
* @param path
* 路径
* @param width
* 宽
* @param height
* 高
* @return
*/
public static String buildQRcode(String contents,
String path,
Integer width,
Integer height) {
MultiFormatWriter multiFormatWriter = new MultiFormatWriter();
// 用于设置QR二维码参数
Map<EncodeHintType, Object> hints = new HashMap<EncodeHintType, Object>();
// 设置编码方式
hints.put(EncodeHintType.CHARACTER_SET, "UTF-8");
// 设置QR二维码的纠错级别（H为最高级别）具体级别信息
hints.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.H);
File file = null;
try {
BitMatrix bitMatrix = multiFormatWriter.encode(contents,
BarcodeFormat.QR_CODE,
width,
height,
hints);
File filepath = new File(path);
if (!filepath.exists()) {
filepath.mkdirs();
}
file = new File(path, System.currentTimeMillis() + ".jpg");
writeToFile(bitMatrix, "jpg", file);
} catch (WriterException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return file.getPath().replace("\\", "/");
}
/**
* 生成带logo二维码
*
* @param contents
* 文本
* @param path
* 路径
* @param width
* 宽
* @param height
* 高
* @param logoPath
* logoPath路径
* @return
*/
public static String buildQRcode(String contents,
String path,
Integer width,
Integer height,
String logoPath) {
MultiFormatWriter multiFormatWriter = new MultiFormatWriter();
// 用于设置QR二维码参数
Map<EncodeHintType, Object> hints = new HashMap<EncodeHintType, Object>();
// 设置编码方式
hints.put(EncodeHintType.CHARACTER_SET, "UTF-8");
// 设置QR二维码的纠错级别（H为最高级别）具体级别信息
hints.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.H);
File file = null;
try {
BitMatrix bitMatrix = multiFormatWriter.encode(contents,
BarcodeFormat.QR_CODE,
width,
height,
hints);
file = new File(path, System.currentTimeMillis() + ".jpg");
writeToFile(bitMatrix, "jpg", file, new File(logoPath));
} catch (WriterException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return file.getPath();
}
/**
* 生成二维码 输出
*
* @param contents
* 文本
* @param path
* 路径
* @param width
* 宽
* @param height
* 高
* @return
*/
public static void buildQRcode(String contents,
Integer width,
Integer height,HttpServletResponse response) {
MultiFormatWriter multiFormatWriter = new MultiFormatWriter();
// 用于设置QR二维码参数
Map<EncodeHintType, Object> hints = new HashMap<EncodeHintType, Object>();
// 设置编码方式
hints.put(EncodeHintType.CHARACTER_SET, "UTF-8");
// 设置QR二维码的纠错级别（H为最高级别）具体级别信息
hints.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.H);
try {
BitMatrix bitMatrix = multiFormatWriter.encode(contents,
BarcodeFormat.QR_CODE,
width,
height,
hints);
OutputStream stream=response.getOutputStream();
writeToStream(bitMatrix, "jpg", stream);
} catch (WriterException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
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 writeToFile(BitMatrix matrix,
String format,
File file,
File logoImg) throws IOException {
BufferedImage image = toBufferedImage(matrix);
// 构建绘图对象
Graphics2D graphics2d = image.createGraphics();
BufferedImage logo = ImageIO.read(logoImg);
int width = logo.getWidth() / 4;
int height = logo.getHeight() / 4;
// 计算图片放置位置
int x = (image.getWidth() - width) / 2;
int y = (image.getHeight() - height) / 2;
graphics2d.drawImage(logo, x, y, width, height, null);
graphics2d.drawRoundRect(x, y, width, height, 15, 15);
graphics2d.setStroke(new BasicStroke(2));// logo默认边框宽度
graphics2d.setColor(Color.WHITE);// logo默认边框颜色
graphics2d.drawRect(x, y, width, height);
graphics2d.dispose();
if (!ImageIO.write(image, format, file)) {
throw new IOException("Could not write an image of format "
+ format + " to " + file);
}
}
//测试
public static void main(String[] args) {
QRcodeKit.buildQRcode("http://yifriend.cn/wxPay/422/16/0/79B4DE7C/userGrant.do", "D://", 500, 500);
}
}