Several methods for java to generate qr code (recommended)

java implements several methods of 2d code generation, specifically as follows:

1: generate 2-dimensional code in the Java project using SwetakeQRCode

http: / / swetake com qr/download address

Or http: / / sourceforge jp/projects/qrcode downloads / 28391 / qrcode zip

This is written by the Japanese, and it generates the 2-dimensional code that we see in squares

You can use Chinese

Such as: 5677777 ghjjjjj

2: generate barcode and 2d code using BarCode4j

BarCode4j url: http: / / sourceforge NET/projects/barcode4j /

barcode4j is a 2-d code generation algorithm using datamatrix, which supports qr

datamatrix is the European and American standard, qr is the Japanese standard,

barcode4j1 looks like a rectangle

Such as: 88777 alec000yan

3: zxing

zxing this is google

Download address: http: / / code google. com p/zxing/downloads/list

Java code:

import java.io.File;  
import java.util.Hashtable;  
 
import com.google.zxing.BarcodeFormat;  
import com.google.zxing.EncodeHintType;  
import com.google.zxing.MultiFormatWriter;  
import com.google.zxing.client.j2se.MatrixToImageWriter;  
import com.google.zxing.common.BitMatrix;  
import com.google.zxing.qrcode.QRCodeWriter;  
 
 
 
public class QRCodeEvents {  
    
  public static void main(String []args)throws Exception{  
    String text = " hello ";  
    int width = 100;  
    int height = 100;  
    String format = "png";  
    Hashtable hints= new Hashtable();  
    hints.put(EncodeHintType.CHARACTER_SET, "utf-8");  
     BitMatrix bitMatrix = new MultiFormatWriter().encode(text, BarcodeFormat.QR_CODE, width, height,hints);  
     File outputFile = new File("new.png");  
     MatrixToImageWriter.writeToFile(bitMatrix, format, outputFile);  
      
  }  
} 

4: google chart api has a way to implement 2-d code

With this api, it is implemented using google appengine.

5: JS generates 2-dimensional code

Generate 2-dimensional code using jQuery-qrcode

jquery - qrcode under simple say 1 first, the open source 3 party libraries (from https: / / github com/jeromeetienne/jquery - qrcode access),

qrcode.js is the core class to realize the calculation of 2d code data.

jquery.qrcode.js encapsulates it in jquery mode and USES it to render graphics, which is actually drawing (canvas and table are supported).

The main supported functions are:

Js code:

text   : "https://github.com/jeromeetienne/jquery-qrcode" // Set up the 2 D code content  

Js code:

render  : "canvas",// Set render mode   
width    : 256,   // Set the width   
height   : 256,   // Set the height   
typeNumber : -1,   // Calculation mode   
correctLevel  : QRErrorCorrectLevel.H,// Error correction level   
background   : "#ffffff",// The background color   
foreground   : "#000000" // The foreground color  

It's very simple to use

Js code:

jQuery('#output').qrcode({width:200,height:200,correctLevel:0,text:content}); 

With simple practice,

The rendering performance of canvas is very good, but if you use table, the performance is not so good, especially for browsers below IE9, so you need to optimize the rendering of table by yourself. I won't go into details here.

One small drawback of js is that it does not support Chinese by default.

This has something to do with the mechanism of js. The library jquery-qrcode USES the method of charCodeAt() for encoding conversion.

By default, this method will get its Unicode encoder, and the decoder like 1 is UTF-8, ISO-8859-1 and so on.

English is no problem, if it is Chinese, Unicode is generally UTF-16, with a length of 2 bits, while UTF-8 is 3 bits, so the encoding and decoding of 2-d code will not match.

The solution, of course, is to convert the string to UTF-8 before encoding the 2-d code. The code is as follows:

function utf16to8(str) {  
  var out, i, len, c;  
  out = "";  
  len = str.length;  
  for(i = 0; i < len; i++) {  
  c = str.charCodeAt(i);  
  if ((c >= 0x0001) && (c <= 0x007F)) {  
    out += str.charAt(i);  
  } else if (c > 0x07FF) {  
    out += String.fromCharCode(0xE0 | ((c >> 12) & 0x0F));  
    out += String.fromCharCode(0x80 | ((c >> 6) & 0x3F));  
    out += String.fromCharCode(0x80 | ((c >> 0) & 0x3F));  
  } else {  
    out += String.fromCharCode(0xC0 | ((c >> 6) & 0x1F));  
    out += String.fromCharCode(0x80 | ((c >> 0) & 0x3F));  
  }  
  }  
  return out;  
}