Java实现验证码

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package com.wind.util;

import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.geom.AffineTransform;
import java.awt.geom.Line2D;
import java.awt.image.BufferedImage;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.Random;
import javax.imageio.ImageIO;
import javax.imageio.stream.ImageOutputStream;

/**
 *
 * @author zyong
 * 验证码
 */
public class CheckCode {

    /**
     * 创建一个随机数对象
     */
    Random random = new Random();
    /**
     * 生成的字符集
     */
    private final String character = "0ABC1DEF2GHI3JKL4MNO5PQR6ST7UV8WX9YZ";
    /**
     * 返回生成后的图片字符
     */
    private String checkCode;
    /**
     * 设置生成图片的宽度,默认为65
     */
    private int width = 65;
    /**
     * 设置生成图片的高度,默认为25
     */
    private int height = 25;
    /**
     * 设置图片的类型,默认为BufferedImage.TYPE_INT_RGB
     */
    private int imageType = BufferedImage.TYPE_INT_RGB;

    /**
     *
     * @return 生成图片后的字符
     */
    public String getCheckCode() {
        return checkCode;
    }

    /**
     * 
     * @return 图片的高度
     */
    public int getHeight() {
        return height;
    }

    /**
     *
     * @param height 图片的高度
     */
    public void setHeight(int height) {
        this.height = height;
    }

    /**
     *
     * @return 图片的宽度
     */
    public int getWidth() {
        return width;
    }

    /**
     *
     * @param width 图片的宽度
     */
    public void setWidth(int width) {
        this.width = width;
    }

    /**
     *
     * @return 图片类型
     */
    public int getImageType() {
        return imageType;
    }

    /**
     *
     * @param imageType 图片类型
     */
    public void setImageType(int imageType) {
        this.imageType = imageType;
    }

    /**
     *
     * @return 生成一张图片
     */
    public ByteArrayInputStream buildImage() {

        BufferedImage image = new BufferedImage(this.width, this.height, this.imageType);
        Graphics g = image.getGraphics();
        Graphics2D g2d = (Graphics2D) g;
        g.setColor(this.getColor(200, 250));
        g.fillRect(0, 0, this.width, this.height);
        g.setFont(new Font("Times New Roman", Font.BOLD, 17));
        g.setColor(this.getColor(180, 200));
        /*
         *绘制100条干扰线
         */
        for (int i = 0; i < 100; i++) {
            int x1 = random.nextInt(this.width);
            int y1 = random.nextInt(this.height);
            int x2 = random.nextInt(this.width - 3);
            int y2 = random.nextInt(this.height - 3);
            BasicStroke bs = new BasicStroke(2f, BasicStroke.CAP_BUTT, BasicStroke.JOIN_BEVEL);
            Line2D line = new Line2D.Double(x1, y1, x2, y2);
            g2d.setStroke(bs);
            g2d.draw(line);
            g.setColor(getColor(180, 222));
        }
        StringBuffer codeStr = new StringBuffer();
        for (int i = 0; i < 4; i++) {
            char c = character.charAt(random.nextInt(36));
            codeStr.append(c);
            Color color = new Color(20 + random.nextInt(110), 20 + random.nextInt(110), 20 + random.nextInt(110));
            g.setColor(color);
            /*随机文字,旋转文字到指定角度*/
            AffineTransform trans = new AffineTransform();
            trans.rotate(random.nextInt(10) * i + 3, 5);
            float scaleSize = random.nextFloat() + 0.5f;
            if (scaleSize < 0.8 || scaleSize > 1.1f) {
                scaleSize = 1f;
            }
            trans.scale(scaleSize, scaleSize);
            g2d.setTransform(trans);
            g.drawString(String.valueOf(c), 15 * i + 6, 9);
        }
        this.checkCode = codeStr.toString();
        g.dispose();
        ByteArrayInputStream inputStream = null;
        ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
        try {
            ImageOutputStream imgOutput = ImageIO.createImageOutputStream(outputStream);
            ImageIO.write(image, "JPEG", imgOutput);
            imgOutput.close();
            inputStream = new ByteArrayInputStream(outputStream.toByteArray());
            outputStream.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return inputStream;

    }

    /**
     * 利用随机数，随机生成一个Color颜色的对象
     * @param fc
     * @param bc
     * @return 颜色对象
     */
    private Color getColor(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);
    }
}