java实现后台返回base64图形编码 java实现后台返回base64图形编码

java后台返回base64图形编码

工具类
使用方法

后端返回base64验证码,解析不出来

【java实现后台返回base64图形编码】
java后台返回base64图形编码
工具类

package com.liginfo.app.util; import java.awt.Color; import java.awt.Font; import java.awt.Graphics; import java.awt.Graphics2D; import java.awt.RenderingHints; import java.awt.geom.AffineTransform; import java.awt.image.BufferedImage; import java.io.ByteArrayOutputStream; import java.io.IOException; import java.security.SecureRandom; import java.util.Arrays; import java.util.Random; import javax.imageio.ImageIO; import org.apache.tomcat.util.codec.binary.Base64; import sun.misc.BASE64Encoder; /* * 返回base64验证码的工具类 */public class RandomGraphic {// 默认验证码6位private static int DEFAULT_CODE_NUMBERS = 6; private static Random random = new SecureRandom(); public static String generateCode(){StringBuffer sb = new StringBuffer(); for (int i = 0; i< DEFAULT_CODE_NUMBERS; i++){sb.append(random.nextInt(10)); }return sb.toString(); }public static String generateCode(int numbers){StringBuffer sb = new StringBuffer(); for (int i = 0; i< numbers; i++){sb.append(random.nextInt(10)); }return sb.toString(); }/*** 使用系统默认字符源生成验证码** @param verifySize*验证码长度* @return*/public static String generateVerifyCode(int verifySize) {return generateVerifyCode(verifySize, VERIFY_CODES); }/*** 使用指定源生成验证码** @param verifySize*验证码长度* @param sources*验证码字符源* @return*/public static final String VERIFY_CODES = "23456789ABCDEFGHJKLMNPQRSTUVWXYZ"; public static String generateVerifyCode(int verifySize, String sources) {if (sources == null || sources.length() == 0) {sources = VERIFY_CODES; }int codesLen = sources.length(); Random rand = new Random(System.currentTimeMillis()); StringBuilder verifyCode = new StringBuilder(verifySize); for (int i = 0; i < verifySize; i++) {verifyCode.append(sources.charAt(rand.nextInt(codesLen - 1))); }return verifyCode.toString(); }/*** 输出指定验证码图片流** @param w* @param h* @param code* @throws IOException*/public static String outputImage(int w, int h, String code) throws IOException {int verifySize = code.length(); BufferedImage image = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB); Random rand = new Random(); Graphics2D g2 = image.createGraphics(); g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON); Color[] colors = new Color[5]; Color[] colorSpaces = new Color[] { Color.WHITE, Color.CYAN, Color.GRAY, Color.LIGHT_GRAY, Color.MAGENTA, Color.ORANGE, Color.PINK, Color.YELLOW }; float[] fractions = new float[colors.length]; for (int i = 0; i < colors.length; i++) {colors[i] = colorSpaces[rand.nextInt(colorSpaces.length)]; fractions[i] = rand.nextFloat(); }Arrays.sort(fractions); g2.setColor(Color.GRAY); // 设置边框色g2.fillRect(0, 0, w, h); Color c = getRandColor(200, 250); g2.setColor(c); // 设置背景色g2.fillRect(0, 2, w, h - 4); // 绘制干扰线Random random = new Random(); g2.setColor(getRandColor(160, 200)); // 设置线条的颜色for (int i = 0; i < 20; i++) {int x = random.nextInt(w - 1); int y = random.nextInt(h - 1); int xl = random.nextInt(6) + 1; int yl = random.nextInt(12) + 1; g2.drawLine(x, y, x + xl + 40, y + yl + 20); }// 添加噪点float yawpRate = 0.05f; // 噪声率int area = (int) (yawpRate * w * h); for (int i = 0; i < area; i++) {int x = random.nextInt(w); int y = random.nextInt(h); int rgb = getRandomIntColor(); image.setRGB(x, y, rgb); }shear(g2, w, h, c); // 使图片扭曲g2.setColor(getRandColor(100, 160)); int fontSize = h - 4; Font font = new Font("Algerian", Font.ITALIC, fontSize); g2.setFont(font); char[] chars = code.toCharArray(); for (int i = 0; i < verifySize; i++) {AffineTransform affine = new AffineTransform(); affine.setToRotation(Math.PI / 4 * rand.nextDouble() * (rand.nextBoolean() ? 1 : -1), (w / verifySize) * i + fontSize / 2, h / 2); g2.setTransform(affine); g2.drawChars(chars, i, 1, ((w - 10) / verifySize) * i + 5, h / 2 + fontSize / 2 - 10); }g2.dispose(); String result = null; ByteArrayOutputStream out = new ByteArrayOutputStream(); boolean flag = ImageIO.write(image, "GIF", out); byte[] b = out.toByteArray(); BASE64Encoder base64Encoder = new BASE64Encoder(); //result = base64Encoder.encode(b); result = Base64.encodeBase64String(b); return result; }private static Color getRandColor(int fc, int bc) {if (fc > 255)fc = 255; if (bc > 255)bc = 255; int r = fc + random.nextInt(bc - fc); int g = fc + random.nextInt(bc - fc); int b = fc + random.nextInt(bc - fc); return new Color(r, g, b); }private static int getRandomIntColor() {int[] rgb = getRandomRgb(); int color = 0; for (int c : rgb) {color = color << 8; color = color | c; }return color; }private static int[] getRandomRgb() {int[] rgb = new int[3]; for (int i = 0; i < 3; i++) {rgb[i] = random.nextInt(255); }return rgb; }private static void shear(Graphics g, int w1, int h1, Color color) {shearX(g, w1, h1, color); shearY(g, w1, h1, color); }private static void shearX(Graphics g, int w1, int h1, Color color) {int period = random.nextInt(2); boolean borderGap = true; int frames = 1; int phase = random.nextInt(2); for (int i = 0; i < h1; i++) {double d = (double) (period >> 1) * Math.sin((double) i / (double) period + (6.2831853071795862D * (double) phase) / (double) frames); g.copyArea(0, i, w1, 1, (int) d, 0); if (borderGap) {g.setColor(color); g.drawLine((int) d, i, 0, i); g.drawLine((int) d + w1, i, w1, i); }}}private static void shearY(Graphics g, int w1, int h1, Color color) {int period = random.nextInt(40) + 10; // 50; boolean borderGap = true; int frames = 20; int phase = 7; for (int i = 0; i < w1; i++) {double d = (double) (period >> 1) * Math.sin((double) i / (double) period + (6.2831853071795862D * (double) phase) / (double) frames); g.copyArea(i, 0, 1, h1, 0, (int) d); if (borderGap) {g.setColor(color); g.drawLine(i, (int) d, i, 0); g.drawLine(i, (int) d + h1, i, h1); }}}publicstatic void main(String arg[]){for (int i =0; i<2000; i++){String s = RandomGraphic.generateCode(); System.out.println(s); }}}

使用方法

String code = RandomGraphic.generateVerifyCode(4); String datahttps://www.it610.com/article/= ""; try {data = https://www.it610.com/article/RandomGraphic.outputImage(100,30,code); j.setAttributes(map); } catch (IOException e) {j.setSuccess(false); j.setMsg("获取验证码失败"); // TODO Auto-generated catch blocke.printStackTrace(); }

后端返回base64验证码,解析不出来注意下base64的验证码，有类似data:image/jpg; base64这种前缀，后面才是具体字符串，所以要么后端拼接上前缀，要么前端，才能解析出来。
以上为个人经验，希望能给大家一个参考，也希望大家多多支持脚本之家。