你知道生成二维码的url有长度限制么

因为工作的原因好久没有更新了，今天更新一个在项目中遇到的问题。

因为一个需求需要根据url生成二维码放在宣传海报上，换言之就是生成活动海报。但是总会遇到url超长的活动地址，一开始生成的二维码有的识别不了，还以为生成二维码的方法有问题，结果是url过长了。

查阅资料如下，大家一起长见识一下。

二维码信息容量大：可容纳多达1850个大写字母或2710个数字或1108个字节，或500多个汉字。或者大家见到格外长的就是有问题，平时遇到的都没事，因为都是短链。

只说问题太枯燥了，下面分享java生成二维码的工具类

package com.ai.wesmall.utils;


import com.google.zxing.BarcodeFormat;
import com.google.zxing.EncodeHintType;
import com.google.zxing.MultiFormatWriter;
import com.google.zxing.common.BitMatrix;
import com.google.zxing.qrcode.decoder.ErrorCorrectionLevel;
import javax.imageio.ImageIO;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.File;
import java.util.*;
import com.google.zxing.*;
import com.google.zxing.client.j2se.BufferedImageLuminanceSource;
import com.google.zxing.common.HybridBinarizer;
import org.springframework.util.ResourceUtils;


import java.awt.geom.RoundRectangle2D;
import java.io.OutputStream;
import java.util.Hashtable;


/**
* ClassName QrCodeUtils
*/
public class QrCodeUtils {




private static final String CHARSET = "utf-8";
private static final String FORMAT = "JPG";
// 二维码尺寸
private static final int QRCODE_SIZE = 300;
// LOGO宽度
private static final int LOGO_WIDTH = 60;
// LOGO高度
private static final int LOGO_HEIGHT = 60;


public static BufferedImage createImage(String content, String logoPath, boolean needCompress) throws Exception {
Hashtable<EncodeHintType, Object> hints = new Hashtable<EncodeHintType, Object>();
hints.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.H);
hints.put(EncodeHintType.CHARACTER_SET, CHARSET);
hints.put(EncodeHintType.MARGIN, 0);
BitMatrix bitMatrix = new MultiFormatWriter().encode(content, BarcodeFormat.QR_CODE, QRCODE_SIZE, QRCODE_SIZE,
hints);
int width = bitMatrix.getWidth();
int height = bitMatrix.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, bitMatrix.get(x, y) ? 0xFF000000 : 0xFFFFFFFF);
}
}
if (logoPath == null || "".equals(logoPath)) {
return image;
}
// 插入图片
QrCodeUtils.insertImage(image, logoPath, needCompress);
return image;
}


/**
* 插入LOGO
*
* @param source 二维码图片
* @param logoPath LOGO图片地址
* @param needCompress 是否压缩
* @throws Exception
*/
private static void insertImage(BufferedImage source, String logoPath, boolean needCompress) throws Exception {
System.out.println("logoPath::::::::::"+logoPath);
System.out.println("source::::::::::"+source);


File file = ResourceUtils.getFile(logoPath);
if (!file.exists()) {
throw new Exception("logo file not found.");
}
Image src = ImageIO.read(new File(logoPath));
int width = src.getWidth(null);
int height = src.getHeight(null);
if (needCompress) { // 压缩LOGO
if (width > LOGO_WIDTH) {
width = LOGO_WIDTH;
}
if (height > LOGO_HEIGHT) {
height = LOGO_HEIGHT;
}
Image image = src.getScaledInstance(width, height, Image.SCALE_SMOOTH);
BufferedImage tag = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
Graphics g = tag.getGraphics();
g.drawImage(image, 0, 0, null); // 绘制缩小后的图
g.dispose();
src = image;
}
// 插入LOGO
Graphics2D graph = source.createGraphics();
int x = (QRCODE_SIZE - width) / 2;
int y = (QRCODE_SIZE - height) / 2;
graph.drawImage(src, x, y, width, height, null);
Shape shape = new RoundRectangle2D.Float(x, y, width, width, 6, 6);
graph.setStroke(new BasicStroke(3f));
graph.draw(shape);
graph.dispose();
}


/**
* 生成二维码(内嵌LOGO)
* 二维码文件名随机，文件名可能会有重复
*
* @param content 内容
* @param logoPath LOGO地址
* @param destPath 存放目录
* @param needCompress 是否压缩LOGO
* @throws Exception
*/
public static String encode(String content, String logoPath, String destPath, boolean needCompress) throws Exception {
BufferedImage image = QrCodeUtils.createImage(content, logoPath, needCompress);
mkdirs(destPath);
String fileName = new Random().nextInt(99999999) + "." + FORMAT.toLowerCase();
ImageIO.write(image, FORMAT, new File(destPath + "/" + fileName));
return fileName;
}


/**
* 生成二维码(内嵌LOGO)
* 调用者指定二维码文件名
*
* @param content 内容
* @param logoPath LOGO地址
* @param destPath 存放目录
* @param fileName 二维码文件名
* @param needCompress 是否压缩LOGO
* @throws Exception
*/
public static String encode(String content, String logoPath, String destPath, String fileName, boolean needCompress) throws Exception {
BufferedImage image = QrCodeUtils.createImage(content, logoPath, needCompress);
fileName = fileName.substring(0, fileName.indexOf(".") > 0 ? fileName.indexOf(".") : fileName.length())
+ "." + FORMAT.toLowerCase();
ImageIO.write(image, FORMAT, new File(destPath + "/" + fileName));
//自己的文件服务器地址
return "https://om.51186.com.cn/cloudShopPC"+destPath + "/" + fileName;
}


/**
* 当文件夹不存在时，mkdirs会自动创建多层目录，区别于mkdir．
* (mkdir如果父目录不存在则会抛出异常)
*
* @param destPath 存放目录
*/
public static void mkdirs(String destPath) {
File file = new File(destPath);
if (!file.exists() && !file.isDirectory()) {
file.mkdirs();
}
}


/**
* 生成二维码(内嵌LOGO)
*
* @param content 内容
* @param logoPath LOGO地址
* @param destPath 存储地址
* @throws Exception
*/
public static String encode(String content, String logoPath, String destPath) throws Exception {
return QrCodeUtils.encode(content, logoPath, destPath, false);
}


/**
* 生成二维码
*
* @param content 内容
* @param destPath 存储地址
* @param needCompress 是否压缩LOGO
* @throws Exception
*/
public static String encode(String content, String destPath, boolean needCompress) throws Exception {
return QrCodeUtils.encode(content, null, destPath, needCompress);
}


/**
* 生成二维码
*
* @param content 内容
* @param destPath 存储地址
* @throws Exception
*/
public static String encode(String content, String destPath) throws Exception {
return QrCodeUtils.encode(content, null, destPath, false);
}


/**
* 生成二维码(内嵌LOGO)
*
* @param content 内容
* @param logoPath LOGO地址
* @param output 输出流
* @param needCompress 是否压缩LOGO
* @throws Exception
*/
public static void encode(String content, String logoPath, OutputStream output, boolean needCompress)
throws Exception {
BufferedImage image = QrCodeUtils.createImage(content, logoPath, needCompress);
ImageIO.write(image, FORMAT, output);
}


/**
* 生成二维码
*
* @param content 内容
* @param output 输出流
* @throws Exception
*/
public static void encode(String content, OutputStream output) throws Exception {
QrCodeUtils.encode(content, null, output, false);
}


/**
* 解析二维码
*
* @param file 二维码图片
* @return
* @throws Exception
*/
public static String decode(File file) throws Exception {
BufferedImage image;
image = ImageIO.read(file);
if (image == null) {
return null;
}
BufferedImageLuminanceSource source = new BufferedImageLuminanceSource(image);
BinaryBitmap bitmap = new BinaryBitmap(new HybridBinarizer(source));
Result result;
Hashtable<DecodeHintType, Object> hints = new Hashtable<DecodeHintType, Object>();
hints.put(DecodeHintType.CHARACTER_SET, CHARSET);
result = new MultiFormatReader().decode(bitmap, hints);
String resultStr = result.getText();
return resultStr;
}


/**
* 解析二维码
*
* @param path 二维码图片地址
* @return
* @throws Exception
*/
public static String decode(String path) throws Exception {
return QrCodeUtils.decode(new File(path));
}








public static void main(String[] args) throws Exception {
String qrUrl = "https://www.baidu.com";
//不含Logo
//QrCodeUtils.encode(text, null, "/Users/ianly/Documents/picture", true);
//含Logo，不指定二维码图片名
//QrCodeUtils.encode(text, "/Users/ianly/Documents/picture/google-icon.jpg", "/Users/ianly/Documents/picture/", true);
//含Logo，指定二维码图片名
String logoPath="C:\\Users\\Administrator\\Desktop\\666.png";
String fileName = UUID.randomUUID().toString();
String encode = QrCodeUtils.encode(qrUrl, logoPath, "E:\\app", fileName, true);
System.out.println(encode);
}




}