java 验证码生成源码

import java.awt.Color;
import java.awt.Font;
import java.io.IOException;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.List;
 
import javax.imageio.ImageIO;
import javax.servlet.Servlet;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
 
import org.apache.commons.lang.math.RandomUtils;
 
import nl.captcha.Captcha;
import nl.captcha.Captcha.Builder;
import nl.captcha.gimpy.BlockGimpyRenderer;
import nl.captcha.text.producer.ChineseTextProducer;
import nl.captcha.text.producer.DefaultTextProducer;
import nl.captcha.text.renderer.DefaultWordRenderer;
import nl.captcha.text.renderer.WordRenderer;
 
 
 
public class CaptchaServlet extends HttpServlet implements Servlet {
    private static final long serialVersionUID = 1L;
    private static final String PARAM_HEIGHT = "height"; // 高度 默认为50
 
    private static final String PARAM_WIDTH = "width";// 宽度 默认为200
 
    private static final String PAEAM_NOISE = "noise";// 干扰线条 默认是没有干扰线条
 
    private static final String PAEAM_TEXT = "text";// 文本
 
    protected int _width = 150;
    protected int _height = 40;
    protected boolean _noise = false;
    protected String _text = "number:1,word:1,number:1,number:1,word:1";
 
    /**
     * 初始化过滤器.将配置文件的参数文件赋值
     * 
     * @throws ServletException
     */
    @Override
    public void init() throws ServletException {
        if (getInitParameter(PARAM_HEIGHT) != null) {
            _height = Integer.valueOf(getInitParameter(PARAM_HEIGHT));
        }
 
        if (getInitParameter(PARAM_WIDTH) != null) {
            _width = Integer.valueOf(getInitParameter(PARAM_WIDTH));
        }
 
        if (getInitParameter(PAEAM_NOISE) != null) {
            _noise = Boolean.valueOf(getInitParameter(PAEAM_NOISE));
        }
 
        if (getInitParameter(PAEAM_NOISE) != null) {
            _text = String.valueOf(getInitParameter(PAEAM_TEXT));
        }
    }
 
    /**
     * 因为获取图片只会有get方法
     */
    @Override
    public void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
 
        Builder builder = new Captcha.Builder(_width, _height);
        // 增加边框
        // builder.addBorder();
        // 是否增加干扰线条
        if (_noise == true) {
            builder.addNoise();
        }
        // ----------------自定义字体大小-----------
        // 自定义设置字体颜色和大小 最简单的效果 多种字体随机显示
        List fontList = new ArrayList();
        fontList.add(new Font("微软 雅黑", Font.LAYOUT_NO_START_CONTEXT, 30));// 可以设置斜体之类的
        DefaultWordRenderer dwr = new DefaultWordRenderer(getRandomColor(), fontList);
        // 加入多种颜色后会随机显示 字体空心
 
        WordRenderer wr = dwr;
        // 增加文本，默认为5个随机字符.
        if (_text == null) {
            builder.addText();
        } else {
            String[] ts = _text.split(",");
            for (int i = 0; i