json2picture
專案開發中會遇到,後端生成的json轉換二維碼,前臺頁面可以顯示，這個需求怎麼做？
1:我們知道前端頁面直接寫base64碼,就會顯示圖片

2:那麼後端只要把json轉換為base64碼傳給前段不就可以了嗎？
分析到此結束,直接上程式碼。

-----------------------------QRCodeUtil工具類-----------------------------------------------

package com.**.utilities;

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.*;
import java.util.Hashtable;
import java.util.Random;

import javax.imageio.ImageIO;

import com.google.gson.JsonObject;
import com.google.zxing.BarcodeFormat;
import com.google.zxing.BinaryBitmap;
import com.google.zxing.DecodeHintType;
import com.google.zxing.EncodeHintType;
import com.google.zxing.MultiFormatReader;
import com.google.zxing.MultiFormatWriter;
import com.google.zxing.Result;
import com.google.zxing.client.j2se.BufferedImageLuminanceSource;
import com.google.zxing.common.BitMatrix;
import com.google.zxing.common.HybridBinarizer;
import com.google.zxing.qrcode.decoder.ErrorCorrectionLevel;
import sun.misc.BASE64Encoder;

/**
 * 二維碼工具類
 *
 * @author GeekPlusA
 * @date 2018-10-19
 */
public class QRCodeUtil {
    private static final String CHARSET = "utf-8";
    private static final String FORMAT = "JPG";
    // 二維碼尺寸
    private static final int QRCODE_SIZE = 300;
    // LOGO寬度
    private static final int LOGO_WIDTH = 60;
    // LOGO高度
    private static final int LOGO_HEIGHT = 60;

    private static BufferedImage createImage(String content, String logoPath, boolean needCompress) throws Exception {
        Hashtable<EncodeHintType, Object> hints = new Hashtable<EncodeHintType, Object>();
        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 (logoPath == null || "".equals(logoPath)) {
            return image;
        }
        // 插入圖片
        QRCodeUtil.insertImage(image, logoPath, needCompress);
        return image;
    }

    /**
     * 插入LOGO
     *
     * @param source       二維碼圖片
     * @param logoPath     LOGO圖片地址
     * @param needCompress 是否壓縮
     * @throws Exception
     */
    private static void insertImage(BufferedImage source, String logoPath, boolean needCompress) throws Exception {
        File file = new File(logoPath);
        if (!file.exists()) {
            throw new Exception("logo file not found.");
        }
        Image src = ImageIO.read(new File(logoPath));
        int width = src.getWidth(null);
        int height = src.getHeight(null);
        if (needCompress) { // 壓縮LOGO
            if (width > LOGO_WIDTH) {
                width = LOGO_WIDTH;
            }
            if (height > LOGO_HEIGHT) {
                height = LOGO_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();
    }

    /**
     * 生成二維碼(內嵌LOGO)
     * 二維碼檔名隨機，檔名可能會有重複
     *
     * @param content      內容
     * @param logoPath     LOGO地址
     * @param destPath     存放目錄
     * @param needCompress 是否壓縮LOGO
     * @throws Exception
     */
    public static String encode(String content, String logoPath, String destPath, boolean needCompress) throws Exception {
        BufferedImage image = QRCodeUtil.createImage(content, logoPath, needCompress);
        mkdirs(destPath);
        String fileName = new Random().nextInt(99999999) + "." + FORMAT.toLowerCase();
        ImageIO.write(image, FORMAT, new File(destPath + "/" + fileName));
        return fileName;
    }

    /**
     * 生成二維碼(內嵌LOGO)
     * 呼叫者指定二維碼檔名
     *
     * @param content      內容
     * @param logoPath     LOGO地址
     * @param destPath     存放目錄
     * @param fileName     二維碼檔名
     * @param needCompress 是否壓縮LOGO
     * @throws Exception
     */
    public static String encode(String content, String logoPath, String destPath, String fileName, boolean needCompress) throws Exception {
        BufferedImage image = QRCodeUtil.createImage(content, logoPath, needCompress);
        mkdirs(destPath);
        fileName = fileName.substring(0, fileName.indexOf(".") > 0 ? fileName.indexOf(".") : fileName.length())
                + "." + FORMAT.toLowerCase();
        ImageIO.write(image, FORMAT, new File(destPath + "/" + fileName));
        return fileName;
    }

    /**
     * 當資料夾不存在時，mkdirs會自動建立多層目錄，區別於mkdir．
     * (mkdir如果父目錄不存在則會丟擲異常)
     *
     * @param destPath 存放目錄
     */
    public static void mkdirs(String destPath) {
        File file = new File(destPath);
        if (!file.exists() && !file.isDirectory()) {
            file.mkdirs();
        }
    }

    /**
     * 生成二維碼(內嵌LOGO)
     *
     * @param content  內容
     * @param logoPath LOGO地址
     * @param destPath 儲存地址
     * @throws Exception
     */
    public static String encode(String content, String logoPath, String destPath) throws Exception {
        return QRCodeUtil.encode(content, logoPath, destPath, false);
    }

    /**
     * 生成二維碼
     *
     * @param content      內容
     * @param destPath     儲存地址
     * @param needCompress 是否壓縮LOGO
     * @throws Exception
     */
    public static String encode(String content, String destPath, boolean needCompress) throws Exception {
        return QRCodeUtil.encode(content, null, destPath, needCompress);
    }

    /**
     * 生成二維碼
     *
     * @param content  內容
     * @param destPath 儲存地址
     * @throws Exception
     */
    public static String encode(String content, String destPath) throws Exception {
        return QRCodeUtil.encode(content, null, destPath, false);
    }

    /**
     * 生成二維碼(內嵌LOGO)
     *
     * @param content      內容
     * @param logoPath     LOGO地址
     * @param output       輸出流
     * @param needCompress 是否壓縮LOGO
     * @throws Exception
     */
    public static void encode(String content, String logoPath, OutputStream output, boolean needCompress)
            throws Exception {
        BufferedImage image = QRCodeUtil.createImage(content, logoPath, needCompress);
        ImageIO.write(image, FORMAT, output);
    }

    /**
     * 生成二維碼
     *
     * @param content 內容
     * @param output  輸出流
     * @throws Exception
     */
    public static void encode(String content, OutputStream output) throws Exception {
        QRCodeUtil.encode(content, null, output, false);
    }

    /**
     * 解析二維碼
     *
     * @param file 二維碼圖片
     * @return
     * @throws Exception
     */
    public static String decode(File file) throws Exception {
        BufferedImage image;
        image = ImageIO.read(file);
        if (image == null) {
            return null;
        }
        BufferedImageLuminanceSource source = new BufferedImageLuminanceSource(image);
        BinaryBitmap bitmap = new BinaryBitmap(new HybridBinarizer(source));
        Result result;
        Hashtable<DecodeHintType, Object> hints = new Hashtable<DecodeHintType, Object>();
        hints.put(DecodeHintType.CHARACTER_SET, CHARSET);
        result = new MultiFormatReader().decode(bitmap, hints);
        String resultStr = result.getText();
        return resultStr;
    }

    /**
     * 解析二維碼
     *
     * @param path 二維碼圖片地址
     * @return
     * @throws Exception
     */
    public static String decode(String path) throws Exception {
        return QRCodeUtil.decode(new File(path));
    }

    /**
     * 二維碼轉換為base64字串
     *
     * @param path 二維碼圖片地址
     * @return
     * @throws Exception
     */
    public static String image2base64(String path) {
        String imgStr = "";
        try {
            File file = new File(path);
            FileInputStream fis = new FileInputStream(file);
            byte[] buffer = new byte[(int) file.length()];
            int offset = 0;
            int numRead = 0;
            while (offset < buffer.length && (numRead = fis.read(buffer, offset, buffer.length - offset)) >= 0) {
                offset += numRead;
            }

            if (offset != buffer.length) {
                throw new IOException("Could not completely read file "
                        + file.getName());
            }
            fis.close();
            BASE64Encoder encoder = new BASE64Encoder();
            imgStr = encoder.encode(buffer);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return "data:image/jpeg;base64," + imgStr;
    }

    /**
     * json轉換為base64字串
     *
     * @param json json字串
     * @return
     * @throws Exception
     */
    public static String json2base64(String json){
        String path = "D:\\";
        String base64Str = null;
        try{
            String str = QRCodeUtil.encode(json,path);
            base64Str = QRCodeUtil.image2base64(path + str);
        }catch (Exception e){
            e.getMessage();
        }
        return StringUtil.leftRightCenterTrim(base64Str);
    }

    public static void main(String[] args) throws Exception {
        String text = "{ \"GeekPlusA\": \"GeekPlusA\", \"GeekPlusA\": \"GeekPlusA\" }";
        String json = QRCodeUtil.json2base64(text);
        System.out.println(json);
        System.out.println(StringUtil.leftRightCenterTrim(json));
    }

}

 

-----------------------------StringUtil工具類-----------------------------------------------

package com.**.utilities;

import com.google.common.base.Strings;

import java.util.*;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 * 字串操作的幫助函式
 *
 * @author GeekPlusA
 */
public abstract class StringUtil {
	/**
     * 去掉字串前後中間空白、換行、製表
     *
     * @param str 字串
     * @return 新字串
     */
    public static String leftRightCenterTrim(String str){
        String dest = "";
        if (null != str) {
            Pattern p = Pattern.compile("\\s*|\t|\r|\n");
            Matcher m = p.matcher(str);
            dest = m.replaceAll("");
        }
        return dest;
    }
}