在java中生成二维码，并直接输出到jsp页面

在java中生成的二维码不存到磁盘里要直接输出到页面上，这就需要把生成的二维码直接以流的形式输出到页面上，我用的是myeclipse 和 tomcat

它的原理是：在加载页面时，根据img的src(code.jspx)找到对应的servlet(CodeServlet)，在servlet中编辑二维码中的内容，调用生成二维码的类EncoderHandler中的encoderQRcoder方法

1.首先要导入jar包（将jar包放到lib目录下）

导入jar包的名称为：Qrcode_swetake

下载jar包的连接http://download.csdn.net/detail/huakaihualuo1223/4527504

2.在java中生成二维码并以流的形式输出

[java] view
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package com.kaishengit.util;

import java.awt.Color;

import java.awt.Graphics2D;

import java.awt.image.BufferedImage;

import javax.imageio.ImageIO;

import javax.servlet.http.HttpServletResponse;

import com.swetake.util.Qrcode;

public class EncoderHandler {

public void encoderQRCoder(String content, HttpServletResponse response) {

try {

Qrcode handler = new Qrcode();

handler.setQrcodeErrorCorrect('M');

handler.setQrcodeEncodeMode('B');

handler.setQrcodeVersion(7);

System.out.println(content);

byte[] contentBytes = content.getBytes("UTF-8");

BufferedImage bufImg = new BufferedImage(80, 80, BufferedImage.TYPE_INT_RGB);

Graphics2D gs = bufImg.createGraphics();

gs.setBackground(Color.WHITE);

gs.clearRect(0, 0, 140, 140);

//设定图像颜色：BLACK

gs.setColor(Color.BLACK);

//设置偏移量 不设置肯能导致解析出错

int pixoff = 2;

//输出内容：二维码

if(contentBytes.length > 0 && contentBytes.length < 124) {

boolean[][] codeOut = handler.calQrcode(contentBytes);

for(int i = 0; i < codeOut.length; i++) {

for(int j = 0; j < codeOut.length; j++) {

if(codeOut[j][i]) {

gs.fillRect(j * 3 + pixoff, i * 3 + pixoff,3, 3);

}

}

}

} else {

System.err.println("QRCode content bytes length = " + contentBytes.length + " not in [ 0,120 ]. ");

}

gs.dispose();

bufImg.flush();

//生成二维码QRCode图片

ImageIO.write(bufImg, "jpg", response.getOutputStream());

} catch (Exception e) {

e.printStackTrace();

}

}

}

3.建立一个servlet

[java] view
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package com.kaishengit.web;

import java.io.IOException;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import com.kaishengit.util.EncoderHandler;

public class CodeServlet extends HttpServlet {

private static final long serialVersionUID = 1L;

@Override

protected void service(HttpServletRequest requset, HttpServletResponse response)

throws ServletException, IOException {

String content = "姓名:maysnow 电话:123687495";

EncoderHandler encoder = new EncoderHandler();

encoder.encoderQRCoder(content, response);

}

}

4在web.xml中的配置

[html] view
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<servlet>

<servlet-name>CodeService</servlet-name>

<servlet-class>com.kaishengit.web.CodeServlet</servlet-class>

</servlet>

<servlet-mapping>

<servlet-name>CodeService</servlet-name>

<url-pattern>/code.jspx</url-pattern>

</servlet-mapping>

5.jsp中的img(其中img的src为对应的CodeServlet的url)

[html] view
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<img style="height:80px;width:80px" src="code.jspx" />

6.页面中生成的二维码