java实现后台返回base64图形编码

目录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

* @rethttp://urn

*/

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 stahttp://tic 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);

}

}

}

public static 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 data = "";

try {

data = 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 block

e.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。

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