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[Java教程]手把手教你生成二维码


一、目标

输入网址,生成网址的二维码

二、概况

1.效果:UI丑,但功能实现了

 

2.项目目录

 

三、用到的第三方资源

1.google的扫码包zxing

2.JQuery

四、步骤(用myEclipse)

1.新建工程,选择web project

2.加入第三方资源(zxing包和jQuery)

2.1

2.1.1复制,粘贴,加入zxing的jar包(所有文件在附件中下载)

2.2.2右键jar包加入buildpath

2.2加入jQuery文件

2.2.1在WebRoot下新建文件夹js

复制粘贴jQuery文件到此文件夹

3.按需求修改webroot下的index.jsp页面如下:

<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%><%String path = request.getContextPath();String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html> <head>  <base href="<%=basePath%>">  <title>二维码</title>  <script src="js/jquery.min.js"></script>  <script>  	$(function(){  		$("input[type=submit]").click(function(e){  			e.preventDefault();  			$("#qrcode_div").empty().append("<img id='qrImg' />");  			$("#qrImg").attr("src", "qrcode?website="+$("input[type=text][name=website]").val());//此处会访问servlet  		});  	});  </script> </head>  <body>  <form>  	网址<input type="text" name="website" />  	<input type="submit" value="生成二维码" />  	<div id="qrcode_div"></div>  </form> </body></html>

4.新建servlet文件

4.1右键工程文件夹--》new ---->servlet(myEclipse会自动配置servlet到web.

QRCode.java servlet文件的代码如下:

package servlet;import java.io.IOException;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import util.QRCodeUtil;import com.google.zxing.WriterException;public class QRCode extends HttpServlet {		public void doGet(HttpServletRequest request, HttpServletResponse response)			throws ServletException, IOException {				request.setCharacterEncoding("utf-8");		response.setCharacterEncoding("utf-8");		String website = request.getParameter("website");		try {			QRCodeUtil.genGR(website, response.getOutputStream());		} catch (WriterException e) {			e.printStackTrace();		}		//String website = request.getAttribute("website").toString();	}	public void doPost(HttpServletRequest request, HttpServletResponse response)			throws ServletException, IOException {		doGet(request, response);	}}

5.新建辅助类文件,作用是生成二维码(QRCodeUtil.java)

5.1右键工程文件夹--》new--->class,如下图

 

QRCodeUtil.java的代码如下:

package util2;import java.awt.image.BufferedImage;import java.io.IOException;import java.io.OutputStream;import java.util.Hashtable;import javax.imageio.ImageIO;import com.google.zxing.BarcodeFormat;import com.google.zxing.EncodeHintType;import com.google.zxing.MultiFormatWriter;import com.google.zxing.WriterException;import com.google.zxing.common.BitMatrix;public class QRCodeUtil {		private static final int BLACK = 0xFF000000;	private static final int WHITE = 0xFFFFFFFF;		public static void genGR(String website, OutputStream output) throws WriterException, IOException {		int width = 300;		int height = 300;		String format = "jpg";    Hashtable<EncodeHintType, String> hints = new Hashtable<EncodeHintType, String>();     //Hashtable hints = new Hashtable();    hints.put(EncodeHintType.CHARACTER_SET, "utf-8");		BitMatrix bm = new MultiFormatWriter().encode(website, BarcodeFormat.QR_CODE, width, height, hints);				BufferedImage image = toImage(bm);		ImageIO.write(image, format, output);	//把二维码写到response的输出流	}	private static BufferedImage toImage(BitMatrix bm) {		int width = bm.getWidth();		int height = bm.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, bm.get(x, y) ? BLACK : WHITE);			}		}		return image;	}}

6.至此,所有文件已完成,接下来布置项目,启动tomcat,访问文件,如下图

布置完成后,点击debug启动项目

启动成功后,在浏览器中访问文件

PS:

可以修改QRCodeUtil.java文件中的颜色配置,以生成彩色的二维码,例如:

private static final int BLACK = 0xff0000ff;//0xFF000000;
private static final int WHITE = 0xffffff00;//0xFFFFFFFF;

常见颜色代码如下:

这些颜色常数是定义在android.graphics.Color里的:

类型

常数

色码

int

BLACK

-16777216

0xff000000

int

BLUE

-16776961

0xff0000ff

int

CYAN

-16711681

0xff00ffff

int

DKGRAY

-12303292

0xff444444

int

GRAY

-7829368

0xff888888

int

GREEN

-16711936

0xff00ff00

int

LTGRAY

-3355444

0xffcccccc

int

MAGENTA

-65281

0xffff00ff

int

RED

-65536

0xffff0000

int

TRANSPARENT

0

0x00000000

int

WHITE

-1

0xffffffff

int

YELLOW

-256

0xffffff00


 

项目附件:

http://files.cnblogs.com/files/shamgod/QRCode.zip