[代碼整理] 使用zxing生成二維碼並前臺顯示！

使用zxing生成二維碼並前臺顯示

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##業務需求：
近期項目中要使用將信息存入二維碼，供用戶微信掃描讀取！提高實際工作中得工作效率

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##思路：
-**1.在前臺將需要生成得信息，通過servlet傳入後端
-**2.將信息進行處理，使用zxing生成二維碼圖片！
-**3.因爲要返回到前臺所以就不生成具體圖片文件。所以直接將生成的二維碼二進制圖片流
-**4.將得到的圖片流，通過輸出流傳到前臺

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##工具簡介：
ZXing是一個開放源碼的，用Java實現的多種格式的1D/2D條碼圖像處理庫，它包含了聯繫到其他語言的端口。Zxing可以實現使用手機的內置的攝像頭完成條形碼的掃描及解碼。該項目可實現的條形碼編碼和解碼。

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##方法實現：

1.通過maven引入zxing的jar包

<dependency>
	<groupId>com.google.zxing</groupId>
	<artifactId>core</artifactId>
	<version>3.3.1</version>
</dependency>
<dependency>
	<groupId>com.google.zxing</groupId>
	<artifactId>javase</artifactId>
	<version>3.3.1</version>
</dependency>

2.寫QRUtils工具包

import java.awt.BasicStroke;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.Shape;
import java.awt.geom.RoundRectangle2D;
import java.awt.image.BufferedImage;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.util.Arrays;
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.common.BitMatrix;
import com.google.zxing.qrcode.decoder.ErrorCorrectionLevel;


public class QRCodeUtil {

    private static final String CHARSET = "utf-8";
    private static final String FORMAT_NAME = "JPG";
    // 二維碼尺寸
    private static final int QRCODE_SIZE = 300;
    // LOGO寬度
    private static final int WIDTH = 60;
    // LOGO高度
    private static final int HEIGHT = 60;

    private static BufferedImage createImage(String content, String imgPath,
                                             boolean needCompress) throws Exception {
        Hashtable hints = new Hashtable();
        hints.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.H);
        hints.put(EncodeHintType.CHARACTER_SET, CHARSET);
        hints.put(EncodeHintType.MARGIN, 1);
        BitMatrix bitMatrix = new MultiFormatWriter().encode(content,
                BarcodeFormat.QR_CODE, QRCODE_SIZE, QRCODE_SIZE, hints);
        int width = bitMatrix.getWidth();
        int height = bitMatrix.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, bitMatrix.get(x, y) ? 0xFF000000
                        : 0xFFFFFFFF);
            }
        }
        if (imgPath == null || "".equals(imgPath)) {
            return image;
        }
        // 插入圖片
        QRCodeUtil.insertImage(image, imgPath, needCompress);
        return image;
    }


    private static void insertImage(BufferedImage source, String imgPath,
                                    boolean needCompress) throws Exception {
        File file = new File(imgPath);
        if (!file.exists()) {
            System.err.println(""+imgPath+"   該文件不存在！");
            return;
        }
        Image src = ImageIO.read(new File(imgPath));
        int width = src.getWidth(null);
        int height = src.getHeight(null);
        if (needCompress) { // 壓縮LOGO
            if (width > WIDTH) {
                width = WIDTH;
            }
            if (height > HEIGHT) {
                height = HEIGHT;
            }
            Image image = src.getScaledInstance(width, height,
                    Image.SCALE_SMOOTH);
            BufferedImage tag = new BufferedImage(width, height,
                    BufferedImage.TYPE_INT_RGB);
            Graphics g = tag.getGraphics();
            g.drawImage(image, 0, 0, null); // 繪製縮小後的圖
            g.dispose();
            src = image;
        }
        // 插入LOGO
        Graphics2D graph = source.createGraphics();
        int x = (QRCODE_SIZE - width) / 2;
        int y = (QRCODE_SIZE - height) / 2;
        graph.drawImage(src, x, y, width, height, null);
        Shape shape = new RoundRectangle2D.Float(x, y, width, width, 6, 6);
        graph.setStroke(new BasicStroke(3f));
        graph.draw(shape);
        graph.dispose();
    }

    //獲取生成二維碼的圖片流
    public static ByteArrayOutputStream encodeIO(String content,String imgPath,Boolean needCompress) throws Exception {
        BufferedImage image = QRCodeUtil.createImage(content, imgPath,
                needCompress);
        //創建儲存圖片二進制流的輸出流
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        //將二進制數據寫入ByteArrayOutputStream
        ImageIO.write(image, "jpg", baos);
		return baos;
	}
    //測試
    public static void main(String[] args) throws Exception {
        String text = "ifarm";
        //QRCodeUtil.encode(text, "D:\\圖片\\武僧2.jpg", "d:/MyWorkDoc", true);
        //String decode = QRCodeUtil.decode("D:\\MyWorkDoc\\32533141.jpg");
        ByteArrayOutputStream encodeIO = QRCodeUtil.encodeIO(text, "D:\\圖片\\武僧2.jpg", true);
        //輸入數組
     System.out.println(Arrays.toString(encodeIO.toByteArray()));
    }
}

3.後臺Controller

@RequestMapping(value = "/getQRCode", method = RequestMethod.GET)
public void getQRCode(HttpServletRequest request, HttpServletResponse response) throws Exception {
	//獲取前臺傳入的信息，此處可操作性很大，大家可以通過自己查詢數據庫，或者通過判斷填入其他信息
      String content = request.getParameter("content");
      //二維碼圖片中間logo
      String imgPath = "";
	Boolean needCompress = true; 
	//通過調用我們的寫的工具類，拿到圖片流
	ByteArrayOutputStream out = QRCodeUtil.encodeIO(content, imgPath, needCompress);
	//定義返回參數
	response.setCharacterEncoding("UTF-8");
	response.setContentType("image/jpeg;charset=UTF-8");
	response.setContentLength(out.size());
	ServletOutputStream outputStream = response.getOutputStream();
	outputStream.write(out.toByteArray());
	outputStream.flush();
	outputStream.close();
}

4.前端
-html

<h1>測試二維碼頁面</h1>
<div class="input-group">
	<span class="input-group-addon" >耳號</span>
	<input type="text" class="form-control" placeholder="請輸入" id="swineEar">
	<span class="input-group-addon"><i class="glyphicon glyphicon-search"></i></span>
 </div>
 <div>
	<div style="float: left;">
	<img src="" id="npcImg" width="300" height="300"/>
	<input type="hidden" id="photo" name="photo"/>
	</div>
</div>

-js

function doCode () {
    $('#npcImg').removeAttr('src')
    var npcName = document.getElementById("swineEar").value;
    if(npcName === ''){
        alert('耳號爲空，不能生成二維碼')
    }else{
        var img = document.getElementById("npcImg");
        img.src = '/getQRCode?content='+npcName;
    }
}

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##總結：
記錄再此爲爲自己總結，也希望能夠幫到其他人！
具體步驟解析，在代碼中都有註釋，應該不需要做過多解釋了。希望能對大家有所幫助！
正常項目中使用直接copy過去直接就能使用了！
覺得不錯的話，點個拇指！