一个Java实现的把指定字符串生成二维码并保存成图片的代码

package qrCode;

import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
import jp.sourceforge.qrcode.QRCodeDecoder;
import jp.sourceforge.qrcode.data.QRCodeImage;

public class GucasQRCodeDecoder {
public GucasQRCodeDecoder() {

}

/**
* decode qrcode image.
* @param qrcodePicfilePath
* @return decoding value.
*/
public static String decode(String qrcodePicfilePath) {
File imageFile = new File(qrcodePicfilePath);
BufferedImage image = null;
try {
image = ImageIO.read(imageFile);
} catch (IOException e) {
System.out.println("Decoding failed, read QRCode image error: " + e.getMessage());
return null;
}
/*
try {
String decodedData = new String(decoder.decode(new J2SEImageGucas(image)), "GBK");
System.out.println(decodedData);
} catch (DecodingFailedException dfe) {
System.out.println("Error: " + dfe.getMessage());
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}
*/
QRCodeDecoder decoder = new QRCodeDecoder();
String decodedData = new String(decoder.decode(new J2SEImageGucas(image)));
return decodedData;
}

public static void main(String[] args) {
QRCodeDecoder decoder = new QRCodeDecoder();
File imageFile = new File("qrcode//TestQRCode.png");
BufferedImage image = null;
try {
image = ImageIO.read(imageFile);
} catch (IOException e) {
System.out.println("Error: " + e.getMessage());
}

String decodedData = new String(decoder.decode(new J2SEImageGucas(image)));
System.out.println(decodedData);
}
}

class J2SEImageGucas implements QRCodeImage {
BufferedImage image;

public J2SEImageGucas(BufferedImage image) {
this.image = image;
}

public int getWidth() {
return image.getWidth();
}

public int getHeight() {
return image.getHeight();
}

public int getPixel(int x, int y) {
return image.getRGB(x, y);
}
}

package qrCode;

import java.awt.Color;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;

import javax.imageio.ImageIO;
import com.swetake.util.Qrcode;

public class GucasQRCodeEncoder {

public static int max_data_size_small = 84;
public static int max_data_size_large = 500;

/**
*
* @param srcValue
* @param qrcodePicfilePath
* @return
*/
public static boolean encode(String srcValue, String qrcodePicfilePath) {
return  encode_84(srcValue, qrcodePicfilePath);
}

/**
* Encoding the information to a QRCode, size of the information must be less than 84 byte.
* @param srcValue
* @param qrcodePicfilePath
* @return
*/
public static boolean encode_84(String srcValue, String qrcodePicfilePath) {
int MAX_DATA_LENGTH = max_data_size_small; // the max size of QR code data source
byte[] d = srcValue.getBytes();
int dataLength = d.length;
int imageWidth = 113; // image size must >= QR code size, or else it will
// not be correctly decoded
int imageHeight = imageWidth;
BufferedImage bi = new BufferedImage(imageWidth, imageHeight,
BufferedImage.TYPE_INT_RGB);
Graphics2D g = bi.createGraphics();
g.setBackground(Color.WHITE);
g.clearRect(0, 0, imageWidth, imageHeight);
g.setColor(Color.BLACK);
if (dataLength > 0 && dataLength <= MAX_DATA_LENGTH) {

Qrcode qrcode = new Qrcode();
//错误修正容量
//L水平   7%的字码可被修正
//M水平   15%的字码可被修正
//Q水平   25%的字码可被修正
//H水平   30%的字码可被修正
//QR码有容错能力，QR码图形如果有破损，仍然可以被机器读取内容，最高可以到7%~30%面积破损仍可被读取。

qrcode.setQrcodeErrorCorrect('M'); // L, Q, H, by default

qrcode.setQrcodeEncodeMode('B'); // A, N, Ĭ��
qrcode.setQrcodeVersion(5); // 37 bytes, (37-1)*3+2+3-1+1 = 113
boolean[][] b = qrcode.calQrcode(d);
int qrcodeDataLen = b.length;
for (int i = 0; i < qrcodeDataLen; i++) {
for (int j = 0; j < qrcodeDataLen; j++) {
if (b[j][i]) {
g.fillRect(j * 3 + 2, i * 3 + 2, 3, 3);

}
}
}
System.out.println("QR code data length" + qrcodeDataLen);
} else {
System.out.println("Generate QRCode image error! Data size is " + dataLength +", it is lager than 84 bytes.");
return false;
}
g.dispose();
bi.flush();
/* generate image */
File f = new File(qrcodePicfilePath);
String suffix = f.getName().substring(f.getName().indexOf(".")+1, f.getName().length());
try {
ImageIO.write(bi, suffix, f); //"png"
} catch (IOException ioe) {
System.out.println("Generate QRCode image error!" + ioe.getMessage());
return false;
}

return true;
}

/**
* Encoding the information to a QRCode, size of the information must be less tah 500 byte.
* @param srcValue
* @param qrcodePicfilePath
* @return
*/
public static boolean encode_500(String srcValue, String qrcodePicfilePath) {
int MAX_DATA_LENGTH = max_data_size_large;
byte[] d = srcValue.getBytes();
int dataLength = d.length;
int imageWidth = 269;
int imageHeight = imageWidth;
BufferedImage bi = new BufferedImage(imageWidth, imageHeight,
BufferedImage.TYPE_INT_RGB);
Graphics2D g = bi.createGraphics();
g.setBackground(Color.WHITE);
g.clearRect(0, 0, imageWidth, imageHeight);
g.setColor(Color.BLACK);
if (dataLength > 0 && dataLength <= MAX_DATA_LENGTH) {
/* ��ɶ�ά�� */
Qrcode qrcode = new Qrcode();
qrcode.setQrcodeErrorCorrect('M');
qrcode.setQrcodeEncodeMode('B');
qrcode.setQrcodeVersion(18); // 0<= version <=40; 89�ֽ�,
// (89-1)*3+2+3-1+1 = 269
boolean[][] b = qrcode.calQrcode(d);
int qrcodeDataLen = b.length;
for (int i = 0; i < qrcodeDataLen; i++) {
for (int j = 0; j < qrcodeDataLen; j++) {
if (b[j][i]) {
g.fillRect(j * 3 + 2, i * 3 + 2, 3, 3);
}
}
}
System.out.println("QR code size" + qrcodeDataLen);
} else {
return false;
}
g.dispose();
bi.flush();
/* generate image */
File f = new File(qrcodePicfilePath);
String suffix = f.getName().substring(f.getName().indexOf(".")+1, f.getName().length());
System.out.println(suffix);
try {
ImageIO.write(bi, suffix, f); //"png"
} catch (IOException ioe) {
System.out.println("Generate QRCode image error!" + ioe.getMessage());
return false;
}

return true;
}

public static void main(String[] args) throws Exception {
System.out.println("trying to encode QRCode...");
String data = "亲，这是用来生成二维码的测试字符串。。。";
System.out.println("total number of source string: " + data.getBytes().length);
GucasQRCodeEncoder.encode(data, "c:\\temp\\A1.JPG");
System.out.println("encoded string: " + GucasQRCodeDecoder.decode("c:\\temp\\A1.JPG"));
}
}

package qrCode;

import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;

import net.glxn.qrgen.QRCode;
import net.glxn.qrgen.image.ImageType;

public class Main {
public static void main(String[] args) {
ByteArrayOutputStream out = QRCode.from("Hello World").to(ImageType.PNG).stream();

try {
FileOutputStream fout = new FileOutputStream(new File(
"C:\\temp\\QR_Code.JPG"));

fout.write(out.toByteArray());

fout.flush();
fout.close();

} catch (FileNotFoundException e) {
// Do Logging
} catch (IOException e) {
// Do Logging
}
}
/* 除了使用QRGen的API来生成数据流，我们还可以使用下面的API来创建QR码：
// get QR file from text using defaults
File file = QRCode.from("Hello World").file();
// get QR stream from text using defaults
ByteArrayOutputStream stream = QRCode.from("Hello World").stream();

// override the image type to be JPG
QRCode.from("Hello World").to(ImageType.JPG).file();
QRCode.from("Hello World").to(ImageType.JPG).stream();

// override image size to be 250x250
QRCode.from("Hello World").withSize(250, 250).file();
QRCode.from("Hello World").withSize(250, 250).stream();

// override size and image type
QRCode.from("Hello World").to(ImageType.GIF).withSize(250, 250).file();
QRCode.from("Hello World").to(ImageType.GIF).withSize(250, 250).stream();

在Java中生成网站链接（URL）的QR码

QR 码最常见的应用便是为网站中一个特定的网页或下载页带来流量。因此，QR码常常会编码URL或网站地址，用户可以通过手机摄像头扫描，并在其浏览器中打开。URL可以直接编码在QR码中。在上面的的Hello World示例中，只需把“Hello World”这个字符串替换为需要编码的URL。下面是代码片段：
ByteArrayOutputStream out = QRCode.from("http://viralpatel.net").to(ImageType.PNG).stream();

*/

}