二维码下载
思路一：
思路二：
当然是思路二比较好，不管从哪个方面讲。Z 直接上思路二的代码：
环境
<!--
环境：easyui、springmvc、maven
需要的jar
-->
<!-- 生成二维码 -->
<dependency>
<groupId>com.google.zxing</groupId>
<artifactId>core</artifactId>
<version>3.1.0</version>
</dependency>
<dependency>
<groupId>commons-codec</groupId>
<artifactId>commons-codec</artifactId>
<version>1.8</version>
</dependency>
<dependency>
<groupId>com.google.zxing</groupId>
<artifactId>javase</artifactId>
<version>3.3.0</version>
</dependency>
前端代码
//下载图片
function downloadPng() {
let imgData,
$.ajax({
type: "POST",
url: "后台接口",
async: false,
data: {id: id},
success: function (downloadUrl) {
imgData = 'data:image/png;base64,' + downloadUrl;
}
});
this.downloadFile('二维码.png', imgData);
}
//下载
function downloadFile(fileName, content) {
let aLink = document.createElement('a');
//new Blob([content]);
let blob = this.base64ToBlob(content);
let evt = document.createEvent("HTMLEvents");
//initEvent 不加后两个参数在FF下会报错 事件类型，是否冒泡，是否阻止浏览器的默认行为
evt.initEvent("click", true, true);
aLink.download = fileName;
aLink.href = URL.createObjectURL(blob);
// aLink.dispatchEvent(evt);
aLink.click()
}
//base64转blob
function base64ToBlob(code) {
let parts = code.split(';base64,');
let contentType = parts[0].split(':')[1];
let raw = window.atob(parts[1]);
let rawLength = raw.length;
let uInt8Array = new Uint8Array(rawLength);
for (let i = 0; i < rawLength; ++i) {
uInt8Array[i] = raw.charCodeAt(i);
}
return new Blob([uInt8Array], {type: contentType});
}
后台代码
// controller 只需要把base64字符串响应给前端就ok，Z 这里直接给工具类
public class ZXingCode {
/**
* 二维码宽度(默认)
*/
private static final int WIDTH = 300;
/**
* 二维码高度(默认)
*/
private static final int HEIGHT = 300;
/**
* 二维码文件格式
*/
private static final String FORMAT = "png";
/**
* 二维码参数
*/
private static final Map<EncodeHintType, Object> hints = new HashMap();
/**
* 默认是黑色
*/
private static final int QRCOLOR = 0xFF000000;
/**
* 背景颜色
*/
private static final int BGWHITE = 0xFFFFFFFF;
static {
//字符编码
hints.put( EncodeHintType.CHARACTER_SET, "utf-8" );
//容错等级 H为最高
hints.put( EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.H );
//边距
hints.put( EncodeHintType.MARGIN, 2 );
}
public static void main(String[] args) {
try {
String a = getLogoQRCode( "https://www.baidu.com/", "跳转到百度的二维码" );
log.info( "------------------:" + a );
} catch (Exception e) {
e.printStackTrace();
}
}
/**
* 生成带logo的二维码图片
*
* @param qrUrl
* @param productName
* @return
*/
public static String getLogoQRCode(String qrUrl, String productName) {
// String filePath = (javax.servlet.http.HttpServletRequest)request.getSession().getServletContext().getRealPath("/") + "resources/static/code/logo.png";
// String filePath = "ClassPath:/resources/static/code/logo.png"; //这个路径有问题，到时候看直接弄绝对路径
//filePath是二维码logo的路径，但是实际中我们是放在项目的某个路径下面的，所以路径用上面的，把下面的注释就好
String filePath = "绝对路径";
String content = qrUrl;
try {
ZXingCode zp = new ZXingCode();
BufferedImage bim = zp.getQR_CODEBufferedImage( content, BarcodeFormat.QR_CODE, 400, 400, zp.getDecodeHintType() );
return zp.addLogo_QRCode( bim, new File( filePath ), new LogoConfig(), productName );
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
/**
* 将二维码图片输出到一个流中
*
* @param content 二维码内容
* @param stream 输出流
* @param width 宽
* @param height 高
*/
public static void writeToStream(String content, OutputStream stream, int width, int height) throws WriterException, IOException {
BitMatrix bitMatrix = new MultiFormatWriter().encode( content, BarcodeFormat.QR_CODE, width, height, hints );
MatrixToImageWriter.writeToStream( bitMatrix, FORMAT, stream );
}
/**
* 给二维码图片添加Logo
*
* @param bim
* @param logoPic
* @param logoConfig
* @param productName
* @return
*/
public String addLogo_QRCode(BufferedImage bim, File logoPic, LogoConfig logoConfig, String productName) {
try {
/**
* 读取二维码图片，并构建绘图对象
*/
BufferedImage image = bim;
Graphics2D g = image.createGraphics();
/**
* 读取Logo图片
*/
BufferedImage logo = ImageIO.read( logoPic );
/**
* 设置logo的大小,本人设置为二维码图片的20%,因为过大会盖掉二维码
*/
int widthLogo = logo.getWidth( null ) > image.getWidth() * 3 / 10 ? (image.getWidth() * 3 / 10) : logo.getWidth( null ), heightLogo =
logo.getHeight( null ) > image.getHeight() * 3 / 10 ? (image.getHeight() * 3 / 10) : logo.getWidth( null );
/**
* logo放在中心
*/
int x = (image.getWidth() - widthLogo) / 2;
int y = (image.getHeight() - heightLogo) / 2;
/**
* logo放在右下角
* int x = (image.getWidth() - widthLogo);
* int y = (image.getHeight() - heightLogo);
*/
//开始绘制图片
g.drawImage( logo, x, y, widthLogo, heightLogo, null );
// g.drawRoundRect(x, y, widthLogo, heightLogo, 15, 15);
// g.setStroke(new BasicStroke(logoConfig.getBorder()));
// g.setColor(logoConfig.getBorderColor());
// g.drawRect(x, y, widthLogo, heightLogo);
g.dispose();
//把商品名称添加上去，商品名称不要太长哦，这里最多支持两行。太长就会自动截取啦
if (productName != null && !productName.equals( "" )) {
//新的图片，把带logo的二维码下面加上文字
BufferedImage outImage = new BufferedImage( 400, 445, BufferedImage.TYPE_4BYTE_ABGR );
Graphics2D outg = outImage.createGraphics();
//画二维码到新的面板
outg.drawImage( image, 0, 0, image.getWidth(), image.getHeight(), null );
//画文字到新的面板
outg.setColor( Color.BLACK );
//字体、字型、字号
outg.setFont( new Font( "宋体", Font.BOLD, 30 ) );
int strWidth = outg.getFontMetrics().stringWidth( productName );
if (strWidth > 399) {
// //长度过长就截取前面部分
// outg.drawString(productName, 0, image.getHeight() + (outImage.getHeight() - image.getHeight())/2 + 5 ); //画文字
//长度过长就换行
String productName1 = productName.substring( 0, productName.length() / 2 );
String productName2 = productName.substring( productName.length() / 2, productName.length() );
int strWidth1 = outg.getFontMetrics().stringWidth( productName1 );
int strWidth2 = outg.getFontMetrics().stringWidth( productName2 );
outg.drawString( productName1, 200 - strWidth1 / 2, image.getHeight() + (outImage.getHeight() - image.getHeight()) / 2 + 12 );
BufferedImage outImage2 = new BufferedImage( 400, 485, BufferedImage.TYPE_4BYTE_ABGR );
Graphics2D outg2 = outImage2.createGraphics();
outg2.drawImage( outImage, 0, 0, outImage.getWidth(), outImage.getHeight(), null );
outg2.setColor( Color.BLACK );
//字体、字型、字号
outg2.setFont( new Font( "宋体", Font.BOLD, 30 ) );
outg2.drawString( productName2, 200 - strWidth2 / 2,
outImage.getHeight() + (outImage2.getHeight() - outImage.getHeight()) / 2 + 5 );
outg2.dispose();
outImage2.flush();
outImage = outImage2;
} else {
//画文字
outg.drawString( productName, 200 - strWidth / 2, image.getHeight() + (outImage.getHeight() - image.getHeight()) / 2 + 12 );
}
outg.dispose();
outImage.flush();
image = outImage;
}
logo.flush();
image.flush();
ByteArrayOutputStream baos = new ByteArrayOutputStream();
baos.flush();
ImageIO.write( image, "png", baos );
/*
二维码生成的路径
*/
ImageIO.write( image, "png", new File(
"绝对路径" + System.currentTimeMillis() + ".png" ) );
BASE64Encoder base64Encoder = new BASE64Encoder();
String imageBase64QRCode = base64Encoder.encode( baos.toByteArray() );
baos.close();
return imageBase64QRCode;
} catch (Exception e) {
e.printStackTrace();
}
return "";
}
/**
* 构建初始化二维码
*
* @param bm
* @return
*/
public BufferedImage fileToBufferedImage(BitMatrix bm) {
BufferedImage image = null;
try {
int w = bm.getWidth(), h = bm.getHeight();
image = new BufferedImage( w, h, BufferedImage.TYPE_INT_RGB );
for (int x = 0; x < w; x++) {
for (int y = 0; y < h; y++) {
image.setRGB( x, y, bm.get( x, y ) ? 0xFF000000 : 0xFFCCDDEE );
}
}
} catch (Exception e) {
e.printStackTrace();
}
return image;
}
/**
* 生成二维码bufferedImage图片
*
* @param content 编码内容
* @param barcodeFormat 编码类型
* @param width 图片宽度
* @param height 图片高度
* @param hints 设置参数
* @return
*/
public BufferedImage getQR_CODEBufferedImage(String content, BarcodeFormat barcodeFormat, int width, int height, Map<EncodeHintType, ?> hints) {
MultiFormatWriter multiFormatWriter = null;
BitMatrix bm = null;
BufferedImage image = null;
try {
multiFormatWriter = new MultiFormatWriter();
// 参数顺序分别为：编码内容，编码类型，生成图片宽度，生成图片高度，设置参数
bm = multiFormatWriter.encode( content, barcodeFormat, width, height, hints );
int w = bm.getWidth();
int h = bm.getHeight();
image = new BufferedImage( w, h, BufferedImage.TYPE_INT_RGB );
// 开始利用二维码数据创建Bitmap图片，分别设为黑（0xFFFFFFFF）白（0xFF000000）两色
for (int x = 0; x < w; x++) {
for (int y = 0; y < h; y++) {
image.setRGB( x, y, bm.get( x, y ) ? QRCOLOR : BGWHITE );
}
}
} catch (WriterException e) {
e.printStackTrace();
}
return image;
}
/**
* 设置二维码的格式参数
*
* @return
*/
public Map<EncodeHintType, Object> getDecodeHintType() {
// 用于设置QR二维码参数
Map<EncodeHintType, Object> hints = new HashMap<EncodeHintType, Object>( 16 );
// 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 );
// 设置编码方式
hints.put( EncodeHintType.CHARACTER_SET, "utf-8" );
hints.put( EncodeHintType.MARGIN, 0 );
hints.put( EncodeHintType.MAX_SIZE, 350 );
hints.put( EncodeHintType.MIN_SIZE, 100 );
return hints;
}
}
class LogoConfig {
// logo默认边框颜色
public static final Color DEFAULT_BORDERCOLOR = Color.WHITE;
// logo默认边框宽度
public static final int DEFAULT_BORDER = 2;
// logo大小默认为照片的1/5
public static final int DEFAULT_LOGOPART = 5;
private final int border = DEFAULT_BORDER;
private final Color borderColor;
private final int logoPart;
/**
* Creates a default config with on color and off color
* , generating normal black-on-white barcodes.
*/
public LogoConfig() {
this( DEFAULT_BORDERCOLOR, DEFAULT_LOGOPART );
}
public LogoConfig(Color borderColor, int logoPart) {
this.borderColor = borderColor;
this.logoPart = logoPart;
}
public Color getBorderColor() {
return borderColor;
}
public int getBorder() {
return border;
}
public int getLogoPart() {
return logoPart;
}
}
结果：
总结：
自己用到的时候方便查找，也希望对你有所帮助。
版权声明：本文由 Ian 在 2018年07月08日发表。本文采用CC BY-NC-SA 4.0许可协议，非商业转载请注明出处，不得用于商业目的。
文章题目及链接：《DownloadBase64Png》
