java程序员菜鸟进阶六之二维码生成与解析

一、概述

二维条码/二维码是用某种特定的几何图形按一定规律在平面（二维方向上）分布的黑白相间的图形记录数据符号信息的；在代码编制上巧妙地利用构成计算机内部逻辑基础的“0”、“1”比特流的概念，使用若干个与二进制相对应的几何形体来表示文字数值信息，通过图象输入设备或光电扫描设备自动识读以实现信息自动处理：它具有条码技术的一些共性：每种码制有其特定的字符集；每个字符占有一定的宽度；具有一定的校验功能等。同时还具有对不同行的信息自动识别功能、及处理图形旋转变化点。

二、java代码生成二维码与解析二维码

1、谷歌的zxing包的使用

2、代码

package com.centaline.controller;

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.EnumMap;

import javax.imageio.ImageIO;

import com.google.zxing.BarcodeFormat;
import com.google.zxing.Binarizer;
import com.google.zxing.BinaryBitmap;
import com.google.zxing.DecodeHintType;
import com.google.zxing.EncodeHintType;
import com.google.zxing.LuminanceSource;
import com.google.zxing.MultiFormatReader;
import com.google.zxing.MultiFormatWriter;
import com.google.zxing.NotFoundException;
import com.google.zxing.Result;
import com.google.zxing.client.j2se.BufferedImageLuminanceSource;
import com.google.zxing.common.BitMatrix;
import com.google.zxing.common.HybridBinarizer;
import com.google.zxing.qrcode.decoder.ErrorCorrectionLevel;

public class zxingTest {

//二维码颜色
private static final int BLACK = 0xFF000000;
//二维码背景颜色
private static final int WHITE = 0xFFFFFFFF;
//二维码宽度
private static final int width = 300;
//二维码高度
private static final int height = 300;

private static final EnumMap<EncodeHintType, Object> hints
= new EnumMap<EncodeHintType, Object>(EncodeHintType.class);
private static final EnumMap<DecodeHintType, Object> hints2 = new EnumMap<DecodeHintType, Object>(DecodeHintType.class);
static{
hints2.put(DecodeHintType.CHARACTER_SET, "UTF-8");
}
//二维码格式参数
static{
hints.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.H); //二维码纠错级别
hints.put(EncodeHintType.MARGIN, 1); //二维码空白边界大小
hints.put(EncodeHintType.CHARACTER_SET, "UTF-8");
hints.put(EncodeHintType.MAX_SIZE, 350);
hints.put(EncodeHintType.MIN_SIZE, 150);
}

/**
* 绘制二维码
* @param contents二维码内容
* @return image二维码图片
*/
public static BufferedImage encodeImg(String contents){
BufferedImage image = null;
try{
BitMatrix matrix = new MultiFormatWriter().encode(contents, BarcodeFormat.QR_CODE, width, height, hints);
image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
int width = matrix.getWidth();
int height = matrix.getHeight();
for(int x = 0; x < width; x++){
for(int y =0;y < height; y++){
image.setRGB(x, y, matrix.get(x, y) ? BLACK : WHITE);
}
}
}catch(Exception e){
System.out.println("生成二维码失败"+e.getMessage());
}
return image;
}

/**
* 二维码输出到文件夹
* @param contents二维码内容
* @param format图片格式
* @param file文件
*/
public static void writeToFile(String contents,String format,File file){
BufferedImage image = encodeImg(contents);
try {
ImageIO.write(image, format, file);
} catch (IOException e) {
System.out.println("二维码写入文件失败"+e.getMessage());
}
}

/**
* 二维码流式输出
* @param contents二维码内容
* @param format图片格式
* @param stream输出
*/
public static void writeToStream(String contents,String format,OutputStream stream){
BufferedImage image = encodeImg(contents);
try {
ImageIO.write(image, format, stream);
} catch (IOException e) {
System.out.println("二维码写入流失败"+e.getMessage());
}
}

/**
* 二维码解析
* @param imgFile文件类
* @return
*/
public static String decodeImg(File imgFile){
String content = null;
if(!imgFile.isFile()){
System.out.println("输入非文件");
return null;
}
try {
BufferedImage image = ImageIO.read(imgFile);
LuminanceSource source = new BufferedImageLuminanceSource(image);
Binarizer binarizer = new HybridBinarizer(source);
BinaryBitmap binaryBitmap = new BinaryBitmap(binarizer);
MultiFormatReader reader = new MultiFormatReader();
Result result = reader.decode(binaryBitmap, hints2);
content = result.getText();
} catch (NotFoundException e) {
System.out.println("二维码解析NotFoundException");
e.printStackTrace();
} catch (IOException e) {
System.out.println("二维码解析IOException");
e.printStackTrace();
}
return content;
}

/**
* 二维码绘制logo
* @param twodimensioncodeImg 二维码图片文件
* @param logoImg logo图片文件
* */
public static BufferedImage encodeImgLogo(File twodimensioncodeImg,File logoImg){
BufferedImage twodimensioncode = null;
try{
if(!twodimensioncodeImg.isFile() || !logoImg.isFile()){
System.out.println("输入非图片");
return null;
}
//读取二维码图片
twodimensioncode = ImageIO.read(twodimensioncodeImg);
//获取画笔
Graphics2D g = twodimensioncode.createGraphics();
//读取logo图片
BufferedImage logo = ImageIO.read(logoImg);
//设置二维码logo大小，太大，会覆盖二维码，此处2
4000
0%
int logoWidth = logo.getWidth(null) > twodimensioncode.getWidth()*2 /10 ? (twodimensioncode.getWidth()*2 /10) : logo.getWidth(null);
int logoHeight = logo.getHeight(null) > twodimensioncode.getHeight()*2 /10 ? (twodimensioncode.getHeight()*2 /10) : logo.getHeight(null);
//设置logo图片放置位置
//中心
int x = (twodimensioncode.getWidth() - logoWidth) / 2;
int y = (twodimensioncode.getHeight() - logoHeight) / 2;
//右下角，15为调整值
// int x = twodimensioncode.getWidth() - logoWidth-15;
// int y = twodimensioncode.getHeight() - logoHeight-15;
//开始合并绘制图片
g.drawImage(logo, x, y, logoWidth, logoHeight, null);
g.drawRoundRect(x, y, logoWidth, logoHeight, 15 ,15);
//logo边框大小
g.setStroke(new BasicStroke(2));
//logo边框颜色
g.setColor(Color.WHITE);
g.drawRect(x, y, logoWidth, logoHeight);
g.dispose();
logo.flush();
twodimensioncode.flush();
}catch(Exception e){
System.out.println("二维码绘制logo失败");
}
return twodimensioncode;
}

/**
* 二维码输出到文件
* @param twodimensioncodeImg 二维码图片文件
* @param logoImg logo图片文件
* @param format 图片格式
* @param file 输出文件
* */
public static void writeToFile(File twodimensioncodeImg,File logoImg,String format,File file){
BufferedImage image = encodeImgLogo(twodimensioncodeImg, logoImg);
try {
ImageIO.write(image, format, file);
} catch (IOException e) {
System.out.println("二维码写入文件失败"+e.getMessage());
}
}

/**
* 二维码流式输出
* @param twodimensioncodeImg 二维码图片文件
* @param logoImg logo图片文件
* @param format 图片格式
* @param stream 输出流
* */
public static void writeToStream(File twodimensioncodeImg,File logoImg,String format,OutputStream stream){
BufferedImage image = encodeImgLogo(twodimensioncodeImg, logoImg);
try {
ImageIO.write(image, format, stream);
} catch (IOException e) {
System.out.println("二维码写入流失败"+e.getMessage());
}
}

/**
* 测试
* @param args
*/
public static void main(String[] args) {
String contents = "http://www.baidu.com";
String format = "jpg"; //***此处如果格式为"gif"，则logo图片为黑色，其他格式ok
//生成二维码
File logoImg = new File("D:"+File.separator+"logo.jpg");
File img = new File("D:"+File.separator+"csdn.jpg");
writeToFile(contents, format, img);
//添加logo图片
File img1 = new File("D:"+File.separator+"csdnlogo.jpg");
writeToFile(img, logoImg, format, img1);

//解析二维码
String content = decodeImg(img);
System.out.println("1:"+content);
//带logo
String content1 = decodeImg(img1);
System.out.println("2:"+content1);
}

}

三、js方式生成二维码

1、QRCode.js 是一个用于生成二维码的 JavaScript 库。主要是通过获取 DOM 的标签,再通过 HTML5 Canvas 绘制而成,不依赖任何库。

2、代码

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="ko" lang="ko">
<head>
<title>JS生成二维码示例</title>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<meta name="viewport" content="width=device-width,initial-scale=1,user-scalable=no" />
<script type="text/javascript" src="resource/jquery/2.1.1/jquery.min.js"></script>
<script type="text/javascript" src="resource/assets/qrcode/qrcode.min.js"></script>
</head>
<body>
<input id="text" type="text" value="http://www.baidu.com" style="width:80%" /><br />
<div id="qrcode" style="width:100px; height:100px; margin-top:15px;"></div>

<script type="text/javascript">
var qrcode = new QRCode(document.getElementById("qrcode"), {
width : 100,
height : 100
});

function makeCode () {
var elText = document.getElementById("text");

if (!elText.value) {
alert("Input a text");
elText.focus();
return;
}

qrcode.makeCode(elText.value);
}

makeCode();

$("#text").
on("blur", function () {
makeCode();
}).
on("keydown", function (e) {
if (e.keyCode == 13) {
makeCode();
}
});
</script>
</body>
</html>