json轉換成圖片工具類
阿新 • • 發佈:2018-11-05
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; } }