java实现电脑端扫描二维码

本文实例为大家分享了java实现电脑端扫描二维码的具体代码，供大家参考，具体内容如下

说明：js调去电脑摄像头拍照，然后获取图片base64位编码，再将base64为编码转为bolb，通过定时异步上传到后台，在后台对图片文件进行解码，返回解码结果到页面，然后页面重新加载结果（url）

第一种方式引入js

<script type="text/javascript" src="${basePath}js/jquery-1.9.min.js"></script>
<script type="text/javascript" src="${basePath}js/jquery.webcam.min.js"></script>

第二种方式引入js

<script type="text/javascript" src="${basePath}js/jquery-1.9.min.js"></script>
<!-- 这个应该是需要的 -->
<script type="text/javascript" src="${basePath}js/jquery.qrcode.min.js"></script>

后台java代码maven引入jar包

 <dependency>
   <groupId>com.github.binarywang</groupId>
   <artifactId>qrcode-utils</artifactId>
   <version>1.1</version>
 </dependency>
 
 <dependency>
   <groupId>com.google.zxing</groupId>
   <artifactId>core</artifactId>
   <version>3.3.3</version>
 </dependency>

后台代码处理方式：

public class EwmDescode {
 
 /**
  * 解析二维码
  * 
  * @param input
  *      二维码输入流
  */
 public static final String parse(InputStream input) throws Exception {
   Reader reader = null;
   BufferedImage image;
   try {
     image = ImageIO.read(input);
     if (image == null) {
       throw new Exception("cannot read image from inputstream.");
     }
     final LuminanceSource source = new BufferedImageLuminanceSource(image);
     final BinaryBitmap bitmap = new BinaryBitmap(new HybridBinarizer(source));
     final Map<DecodeHintType, String> hints = new HashMap<DecodeHintType, String>();
     hints.put(DecodeHintType.CHARACTER_SET, "utf-8");
     // 解码设置编码方式为：utf-8，
     reader = new MultiFormatReader();
     return reader.decode(bitmap, hints).getText();
   } catch (IOException e) {
     e.printStackTrace();
     throw new Exception("parse QR code error: ", e);
   } catch (ReaderException e) {
     e.printStackTrace();
     throw new Exception("parse QR code error: ", e);
     }
   }
 
   /**
  * 解析二维码
  * 
  * @param url
  *      二维码url
  */
 public static final String parse(URL url) throws Exception {
   InputStream in = null;
   try {
     in = url.openStream();
     return parse(in);
   } catch (IOException e) {
     e.printStackTrace();
     throw new Exception("parse QR code error: ", e);
     } finally {
       IOUtils.closeQuietly(in);
     }
   }
 
   /**
  * 解析二维码
  * 
  * @param file
  *      二维码图片文件
  */
 public static final String parse(File file) throws Exception {
   InputStream in = null;
   try {
     in = new BufferedInputStream(new FileInputStream(file));
     return parse(in);
   } catch (FileNotFoundException e) {
     e.printStackTrace();
     throw new Exception("parse QR code error: ", e);
     } finally {
       IOUtils.closeQuietly(in);
     }
   }
 
   /**
  * 解析二维码
  * 
  * @param filePath
  *      二维码图片文件路径
  */
 public static final String parse(String filePath) throws Exception {
   InputStream in = null;
   try {
     in = new BufferedInputStream(new FileInputStream(filePath));
     return parse(in);
   } catch (FileNotFoundException e) {
     e.printStackTrace();
     throw new Exception("parse QR code error: ", e);
   } finally {
     IOUtils.closeQuietly(in);
   }
 }
 
}
@RequestMapping("/decodeEwm")
 @ResponseBody
 public String decodeEwm(MultipartFile ewmImg){
 String parse = null;
 try {
  parse = EwmDescode.parse(ewmImg.getInputStream());
 } catch (Exception e) {
  //e.printStackTrace();
 }
 
 String msg = "no";
 if(StringUtils.isNotBlank(parse)){
  return parse;
 }
 return msg;
 }

前台jsp代码：

第一种处理方式：

<%@ page contentType="text/html; charset=utf-8"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<%
 String path = request.getContextPath();
 String basePath = request.getScheme() + "://" + request.getServerName() + ":" + request.getServerPort()
  + path + "/resources/";
 String urlPath = request.getScheme() + "://" + request.getServerName() + ":" + request.getServerPort()
  + path + "/";
 request.setAttribute("path", path);
 request.setAttribute("basePath", basePath);
 request.setAttribute("urlPath", urlPath);
%>
<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <title>webcam</title>
    <style type="text/css">
      #webcam {
        width: auto;
        height: auto;
        float: left;
      }
      #base64image {
        display: block;
        width: 320px;
        height: 240px;
      }
    </style>
 
    <!-- 基本的jquery引用，1.5版本以上 -->
    <script type="text/javascript" src="${basePath}js/jquery-1.9.min.js"></script>
 
    <!-- webcam插件引用 -->
    <script type="text/javascript" src="${basePath}js/jquery.webcam.min.js"></script>
 
  </head>
 
  <body>
 
    <div id="webcam"></div>
    <canvas id="canvas" width="320" height="240" style="display: none;"></canvas>
    <input id="snapBtn" type="button" value="拍照" style="display: none;"/>
    <img id="base64image" src='' />
 
    <script type="text/javascript">
      
      $(document).ready(function() {
       var pos = 0,
         ctx = null,
         image = [];
       var w = 320;
       var h = 240;
 
        jQuery("#webcam").webcam({
 
          width: 320,
          height: 240,
          mode: "callback",
          swffile: "${basePath}js/jscam_canvas_only.swf", // 这里引入swf文件，注意路径
         // swffile: "/jscam_canvas_only.swf", // 这里引入swf文件，注意路径
          onTick: function(remain) {},
          onSave: function(data) {
 
            var col = data.split(";");
            var img = image;
 
            for(var i = 0; i < 320; i++) {
              var tmp = parseInt(col[i]);
              img.data[pos + 0] = (tmp >> 16) & 0xff;
              img.data[pos + 1] = (tmp >> 8) & 0xff;
              img.data[pos + 2] = tmp & 0xff;
              img.data[pos + 3] = 0xff;
              pos += 4;
            }
 
            if(pos >= 4 * 320 * 240) {
            
              // 将图片显示到canvas中
              ctx.putImageData(img, 0, 0);
              sumitImageFile(canvas.toDataURL("image/png"));
              /* // 取得图片的base64码
              var base64 = canvas.toDataURL("image/png");          
              // 将图片base64码设置给img
              var base64image = document.getElementById('base64image');                               
              base64image.setAttribute('src', base64); */
 
              pos = 0;
 
            }
 
          },
 
          onCapture: function() {
            webcam.save();
            // Show a flash for example
          },
 
          debug: function(type, string) {
            console.log('type:' + type + ',string:' + string);
            // Write debug information to console.log() or a div
          },
 
          onLoad: function() {
            // Page load
          }
 
        });
        window.addEventListener("load", function() {
 
          var canvas = document.getElementById("canvas");
 
          if(canvas.getContext) {
            ctx = canvas.getContext("2d");
            ctx.clearRect(0, 0, 320, 240);
 
            var img = new Image();
            img.onload = function() {
              ctx.drawImage(img, 129, 89);
            }
            image = ctx.getImageData(0, 0, 320, 240);
          }
 
        }, false);
  
        $('#snapBtn').on('click', function() {
          webcam.capture();
        });
      });
      
      setInterval(function () {
       $("#snapBtn").click();
      }, 1500); 
      
      /**
       * @param base64Codes
       *      图片的base64编码
       */
      function sumitImageFile(base64Codes){
       // var form=document.forms[0];
        
       // var formData = new FormData(form);  //这里连带form里的其他参数也一起提交了,如果不需要提交其他参数可以直接FormData无参数的构造函数
        var formData = new FormData();  //这里连带form里的其他参数也一起提交了,如果不需要提交其他参数可以直接FormData无参数的构造函数
        
        //convertBase64UrlToBlob函数是将base64编码转换为Blob
        formData.append("ewmImg",convertBase64UrlToBlob(base64Codes)); //append函数的第一个参数是后台获取数据的参数名,和html标签的input的name属性功能相同
        
        //ajax 提交form
        $.ajax({
          url : '${urlPath}query/decodeEwm',
          type : "POST",
          data : formData,
          dataType:"text",
          processData : false,     // 告诉jQuery不要去处理发送的数据
          contentType : false,    // 告诉jQuery不要去设置Content-Type请求头
          
          success:function(data){
           //alert(data);
           if(data != "no"){
            window.location.href=data;
           }
          },
          xhr:function(){      //在jquery函数中直接使用ajax的XMLHttpRequest对象
            var xhr = new XMLHttpRequest();
            
            xhr.upload.addEventListener("progress", function(evt){
              if (evt.lengthComputable) {
                var percentComplete = Math.round(evt.loaded * 100 / evt.total); 
                console.log("正在提交."+percentComplete.toString() + '%');    //在控制台打印上传进度
              }
            }, false);
            
            return xhr;
          }
          
        });
      }
 
      /**
       * 将以base64的图片url数据转换为Blob
       * @param urlData
       *      用url方式表示的base64图片数据
       */
      function convertBase64UrlToBlob(urlData){
        
        var bytes=window.atob(urlData.split(',')[1]);    //去掉url的头，并转换为byte
        
        //处理异常,将ascii码小于0的转换为大于0
        var ab = new ArrayBuffer(bytes.length);
        var ia = new Uint8Array(ab);
        for (var i = 0; i < bytes.length; i++) {
          ia[i] = bytes.charCodeAt(i);
        }
 
        return new Blob( [ab] , {type : 'image/png'});
      }
      
    </script>
  </body>
 
</html>

第二种处理方式：

<%@ page contentType="text/html; charset=utf-8"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<%
 String path = request.getContextPath();
 String basePath = request.getScheme() + "://" + request.getServerName() + ":" + request.getServerPort()
  + path + "/resources/";
 String urlPath = request.getScheme() + "://" + request.getServerName() + ":" + request.getServerPort()
  + path + "/";
 request.setAttribute("path", path);
 request.setAttribute("basePath", basePath);
 request.setAttribute("urlPath", urlPath);
%>
<!DOCTYPE html>
<html>
<head>
<title>QRCODE</title>
</head>
<script type="text/javascript" src="${basePath}js/jquery-1.9.min.js"></script>
<!-- 这个应该是需要的 -->
<script type="text/javascript" src="${basePath}js/jquery.qrcode.min.js"></script>
<body>
<style>#video {display: block;margin:1em auto;width:280px;height:280px;}</style> 
<video id="video" autoplay></video>
<script>
  window.addEventListener("DOMContentLoaded", function () {
    var video = document.getElementById("video"), canvas, context;
    try {
      canvas = document.createElement("canvas");
      context = canvas.getContext("2d");
    } catch (e) { alert("not support canvas!"); return; }
    
    navigator.getUserMedia = navigator.getUserMedia || navigator.webkitGetUserMedia || navigator.mozGetUserMedia || navigator.msGetUserMedia;
 
    if (navigator.getUserMedia){
      navigator.getUserMedia(
        { "video": true },
        function (stream) {
          if (video.mozSrcObject !== undefined)video.mozSrcObject = stream;
          else video.src = ((window.URL || window.webkitURL || window.mozURL || window.msURL) && window.URL.createObjectURL(stream)) || stream;        
          video.play();
        },
        function (error) {
          if(error.PERMISSION_DENIED){
           alert("用户拒绝了浏览器请求媒体的权限");
          }
           //console.log("用户拒绝了浏览器请求媒体的权限",error.code);
          if(error.NOT_SUPPORTED_ERROR){
           alert("当前浏览器不支持拍照功能");
          }
           //console.log("当前浏览器不支持拍照功能",error.code);
          if(error.MANDATORY_UNSATISFIED_ERROR){
           alert("指定的媒体类型未接收到媒体流");
          }
           //console.log("指定的媒体类型未接收到媒体流",error.code);
          alert("Video capture error: " + error.code);
        }
      );
     //定时扫描
      setInterval(function () {
        context.drawImage(video, 0, 0, canvas.width = video.videoWidth, canvas.height = video.videoHeight);
    sumitImageFile(canvas.toDataURL());
      }, 1500);
    } else {
     alert("扫描出错，换种方式试试！");
    }
    
 
  }, false);
  
  
  /**
   * @param base64Codes
   *      图片的base64编码
   */
  function sumitImageFile(base64Codes){
   // var form=document.forms[0];
    
   // var formData = new FormData(form);  //这里连带form里的其他参数也一起提交了,如果不需要提交其他参数可以直接FormData无参数的构造函数
    var formData = new FormData();  //这里连带form里的其他参数也一起提交了,如果不需要提交其他参数可以直接FormData无参数的构造函数
    
    //convertBase64UrlToBlob函数是将base64编码转换为Blob
    formData.append("ewmImg",convertBase64UrlToBlob(base64Codes)); //append函数的第一个参数是后台获取数据的参数名,和html标签的input的name属性功能相同
    
    //ajax 提交form
    $.ajax({
      url : '${urlPath}query/decodeEwm',
      type : "POST",
      data : formData,
      dataType:"text",
      processData : false,     // 告诉jQuery不要去处理发送的数据
      contentType : false,    // 告诉jQuery不要去设置Content-Type请求头
      
      success:function(data){
       //alert(data);
       if(data != "no"){
        window.location.href=data;
       }
      },
      xhr:function(){      //在jquery函数中直接使用ajax的XMLHttpRequest对象
        var xhr = new XMLHttpRequest();
        
        xhr.upload.addEventListener("progress", function(evt){
          if (evt.lengthComputable) {
            var percentComplete = Math.round(evt.loaded * 100 / evt.total); 
            console.log("正在提交."+percentComplete.toString() + '%');    //在控制台打印上传进度
          }
        }, false);
        
        return xhr;
      }
      
    });
  }
 
  /**
   * 将以base64的图片url数据转换为Blob
   * @param urlData
   *      用url方式表示的base64图片数据
   */
  function convertBase64UrlToBlob(urlData){
    
    var bytes=window.atob(urlData.split(',')[1]);    //去掉url的头，并转换为byte
    
    //处理异常,将ascii码小于0的转换为大于0
    var ab = new ArrayBuffer(bytes.length);
    var ia = new Uint8Array(ab);
    for (var i = 0; i < bytes.length; i++) {
      ia[i] = bytes.charCodeAt(i);
    }
 
    return new Blob( [ab] , {type : 'image/png'});
  }
  
 </script> 
 
</body>
 
</html>

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持社区。