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[Java教程]关于用Java实现二维码的生成


         昨天晚上看了一个视频讲的是web端把名片搞成二维码的形式,觉得挺有意思的,不过我还是初学,所以就没在网页端实现,写了命令行程序.

虽然看着程序很短,不过写的过程中还是出了问题, 最致命的就是

Graphics2D.clearRect(0,0,235,235);
Graphics2D.setColor(Color.BLACK); 
这两句代码顺序搞反,导致生成的二维码异常,不能够被读取其中的信息. 当时检查了好久都没看出问题所在,其实现在来看先设置颜色再clean不就相当于没设置颜色吗,
所以以后一定要小心仔细,争取少犯这种低级错误
 
package com.fantasyado.qrcoder;
import com.swetake.util.Qrcode;

import javax.imageio.ImageIO;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.util.Scanner;

public class Main
{


public static void main(String[] args)
{
// write your code here
String content="";
Scanner sc=new Scanner(System.in);
System.out.println("input your information,and ends with ok");
while(! content.endsWith("ok")){
content=content+"\n";
content=content.concat(sc.next());
}

content=content.substring(1,content.length()-2);
// content=content.replaceAll("ok","");

System.out.println("input your filename ends with EnterKey");
String filename=sc.next();
String filepath="D:\\"+filename+".png";
new Main().drawQRCODE(content, filepath);
System.out.println("draw QR_code successfullly!");
System.out.println(content);

}
public void drawQRCODE(String content,String filepath){
try {
Qrcode qrcode=new Qrcode();

qrcode.setQrcodeErrorCorrect('M');
qrcode.setQrcodeEncodeMode('B');
qrcode.setQrcodeVersion(15);
int width= 235;
int height=235;
BufferedImage image=new BufferedImage(width,height,BufferedImage.TYPE_INT_RGB);
Graphics2D g2=image.createGraphics();
g2.setBackground(Color.WHITE);
g2.clearRect(0,0,235,235);
g2.setColor(Color.BLACK);

byte[] contentbytes=content.getBytes("utf-8");
boolean[][] codeout= qrcode.calQrcode(contentbytes);
for (int i = 0; i <codeout.length; i++) {
for (int j = 0; j < codeout.length; j++) {

if (codeout[j][i]) g2.fillRect(j*3+2,i*3+2,3,3);
}
}
g2.dispose();
image.flush();
File imgFile = new File(filepath);
ImageIO.write(image, "png", imgFile);
}catch (Exception e){
e.printStackTrace();
}
}
}