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前言

根据公司业务需求，需要将指定的url催缴二维码，于是有了以下总结，作为一个记录，以便以后可以用到哦！

一、将url直接生成二维码

package com.xiaojukeji.it.common.util;
import com.google.zxing.BarcodeFormat;
import com.google.zxing.EncodeHintType;
import com.google.zxing.MultiFormatWriter;
import com.google.zxing.common.BitMatrix;
import javax.imageio.ImageIO;
import javax.swing.filechooser.FileSystemView;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
public class QrCodeUtil { 

public static void main(String[] args) { 

String url = "http://www.baidu.com";
String path = FileSystemView.getFileSystemView().getHomeDirectory() + File.separator + "testQrcode";
String fileName = "temp.jpg";
createQrCode(url, path, fileName);
}
public static void createQrCode(String url,String path,String fileName) { 

try { 

Map<EncodeHintType, String> hints = new HashMap<>();
hints.put(EncodeHintType.CHARACTER_SET, "UTF-8");
BitMatrix bitMatrix = new MultiFormatWriter().encode(url, BarcodeFormat.QR_CODE, 400, 400, hints);
File file = new File(path, fileName);
if (file.exists() || ((file.getParentFile().exists() || file.getParentFile().mkdirs()) && file.createNewFile())) { 

writeToFile(bitMatrix, "jpg", file);
System.out.println("二维码图片：" + file);
}
} catch (Exception e) { 

e.printStackTrace();
}
}
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);
}
}
private static final int BLACK = 0xFF000000;
private static final int WHITE = 0xFFFFFFFF;
private 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;
}
}

二、将url生成二维码并以base64返回

上面的方法只能够将url生成二维码，但是如果将此结果返回给前端的话，是无法直接展示的，因为前端需要接收一个base64的字符串，所以下面的方法诞生了

public static String methods(String str) { 

MultiFormatWriter multiFormatWriter = new MultiFormatWriter();
Map hints = new HashMap();
hints.put(EncodeHintType.CHARACTER_SET, "UTF-8"); //设置字符集编码类型
hints.put(EncodeHintType.MARGIN, 1); //设置白边
BitMatrix bitMatrix = null;
try { 

bitMatrix = multiFormatWriter.encode(str, BarcodeFormat.QR_CODE, 300, 300, hints);
BufferedImage image = toBufferedImage(bitMatrix);
ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
//输出二维码图片流
try { 

ImageIO.write(image, "png", outputStream);
return Base64.encodeBase64String(outputStream.toByteArray());
} catch (IOException e) { 

e.printStackTrace();
}
} catch (WriterException e1) { 

e1.printStackTrace();
}
return null;
}
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) ? 0xFF000000 : 0xFFFFFFFF);//0xFF000000黑；0xFFFFFFFF白
}
}
return image;
}
public static void main(String[] args) { 

String methods = methods("http://www.baidu.com"");
System.out.println(methods);
}

这样就大功告成啦！