简要介绍

本个小例子需要引入外部jar包，使用maven创建项目的话，只需要引入依赖即可。本次实现的功能是，在指定位置，生成一张二维码，其他人可以扫描二维码，读取事先写入的文本内容或者是url地址

项目结构

image.png

maven依赖

    <!-- https://mvnrepository.com/artifact/com.google.zxing/core -->
    <dependency>
      <groupId>com.google.zxing</groupId>
      <artifactId>core</artifactId>
      <version>3.3.0</version>
    </dependency>

    <dependency>
      <groupId>com.google.zxing</groupId>
      <artifactId>javase</artifactId>
      <version>3.3.0</version>
    </dependency>

完整的pom.xml文件

<?xml version="1.0" encoding="UTF-8"?>

<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0
  http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <groupId>org.example</groupId>
  <artifactId>erweima</artifactId>
  <version>1.0-SNAPSHOT</version>



  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <maven.compiler.source>1.8</maven.compiler.source>
    <maven.compiler.target>1.8</maven.compiler.target>
  </properties>

  <dependencies>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.11</version>
      <scope>test</scope>
    </dependency>

    <!-- https://mvnrepository.com/artifact/com.google.zxing/core -->
    <dependency>
      <groupId>com.google.zxing</groupId>
      <artifactId>core</artifactId>
      <version>3.3.0</version>
    </dependency>

    <dependency>
      <groupId>com.google.zxing</groupId>
      <artifactId>javase</artifactId>
      <version>3.3.0</version>
    </dependency>


  </dependencies>

  <build>

  </build>
</project>

源码

package org.example;

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;
import com.google.zxing.qrcode.decoder.ErrorCorrectionLevel;

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

/**
 * 二维码
 */
public class QRCode {

    public static void main(String[] args) {
        //图片宽度、高度，二维码和边框的边距
        //二维码的容错等级
        Map map = new HashMap();
        //设置编剧（二维码与图片编剧边框的距离）枚举
        map.put(EncodeHintType.MARGIN,2);
        //设置容错的等级 有四级  L（7%） M(15%) Q(25%)  H(30%)
        map.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.H);
        //设置字符集，避免中文乱码的情况
        map.put(EncodeHintType.CHARACTER_SET,"utf-8");
        //二维码的输出流 IO流
        MultiFormatWriter mfw = new MultiFormatWriter();
        try{
            //通过流创建一个二维矩阵
            BitMatrix bm = mfw.encode("https://www.jianshu.com/u/387316438c8e", BarcodeFormat.QR_CODE,400,400,map);
            //声明一张图片来回值二维码
            BufferedImage img = new BufferedImage(400,400,BufferedImage.TYPE_INT_BGR);
            //将二维码的矩阵回值到图片上
            //重复的做某件事就使用循环结构
            for (int i = 0; i < 400; i++) {
                for (int j = 0; j < 400; j++) {

                    //声明一个颜色
                    int rgb = 0;
                    //画矩阵图
                    rgb = bm.get(i,j) ? Color.BLACK.getRGB() : Color.WHITE.getRGB();
                    //将内容绘制到图片中
                    img.setRGB(i,j,rgb);
                }
            }



            //指定二维码的存储路径
            ImageIO.write(img,"jpg",new File("D:/简书主页.jpg"));
            System.out.println("二维码生成完成");
        }catch(WriterException | IOException e){
            e.printStackTrace();
        }


    }
}