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java後端生成驗證碼

package com.facebac.yun.web.servlet;
import java.util.Random;

import javax.imageio.ImageIO;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import java.awt.image.BufferedImage;
import java.io.IOException;
import java.awt.Graphics;
import java.awt.Font;
import java.awt.Color;

/**
 * 驗證碼生成器類,可生成數字、大寫、小寫字母及三者混合型別的驗證碼。 支援自定義驗證碼字元數量; 支援自定義驗證碼圖片的大小; 支援自定義需排除的特殊字元;
 * 支援自定義干擾線的數量; 支援自定義驗證碼圖文顏色
 */
@WebServlet("/code.jpg")
public class ValidateCode {

	/**
	 * 驗證碼型別為僅數字 0~9
	 */
	public static final int TYPE_NUM_ONLY = 0;

	/**
	 * 驗證碼型別為僅字母,即大寫、小寫字母混合
	 */
	public static final int TYPE_LETTER_ONLY = 1;

	/**
	 * 驗證碼型別為數字、大寫字母、小寫字母混合
	 */
	public static final int TYPE_ALL_MIXED = 2;

	/**
	 * 驗證碼型別為數字、大寫字母混合
	 */
	public static final int TYPE_NUM_UPPER = 3;

	/**
	 * 驗證碼型別為數字、小寫字母混合
	 */
	public static final int TYPE_NUM_LOWER = 4;

	/**
	 * 驗證碼型別為僅大寫字母
	 */
	public static final int TYPE_UPPER_ONLY = 5;

	/**
	 * 驗證碼型別為僅小寫字母
	 */
	public static final int TYPE_LOWER_ONLY = 6;

	private ValidateCode() {

	}

	/**
	 * 生成驗證碼字串
	 * 
	 * @param type
	 *            驗證碼型別,參見本類的靜態屬性
	 * @param length
	 *            驗證碼長度,大於0的整數
	 * @param exChars
	 *            需排除的特殊字元(僅對數字、字母混合型驗證碼有效,無需排除則為null)
	 * @return 驗證碼字串
	 */
	public static String generateTextCode(int type, int length, String exChars) {

		if (length <= 0)
			return "";

		StringBuffer code = new StringBuffer();
		int i = 0;
		Random r = new Random();

		switch (type) {

		// 僅數字
		case TYPE_NUM_ONLY:
			while (i < length) {
				int t = r.nextInt(10);
				if (exChars == null || exChars.indexOf(t + "") < 0) {// 排除特殊字元
					code.append(t);
					i++;
				}
			}
			break;

		// 僅字母(即大寫字母、小寫字母混合)
		case TYPE_LETTER_ONLY:
			while (i < length) {
				int t = r.nextInt(123);
				if ((t >= 97 || (t >= 65 && t <= 90)) && (exChars == null || exChars.indexOf((char) t) < 0)) {
					code.append((char) t);
					i++;
				}
			}
			break;

		// 數字、大寫字母、小寫字母混合
		case TYPE_ALL_MIXED:
			while (i < length) {
				int t = r.nextInt(123);
				if ((t >= 97 || (t >= 65 && t <= 90) || (t >= 48 && t <= 57))
						&& (exChars == null || exChars.indexOf((char) t) < 0)) {
					code.append((char) t);
					i++;
				}
			}
			break;

		// 數字、大寫字母混合
		case TYPE_NUM_UPPER:
			while (i < length) {
				int t = r.nextInt(91);
				if ((t >= 65 || (t >= 48 && t <= 57)) && (exChars == null || exChars.indexOf((char) t) < 0)) {
					code.append((char) t);
					i++;
				}
			}
			break;

		// 數字、小寫字母混合
		case TYPE_NUM_LOWER:
			while (i < length) {
				int t = r.nextInt(123);
				if ((t >= 97 || (t >= 48 && t <= 57)) && (exChars == null || exChars.indexOf((char) t) < 0)) {
					code.append((char) t);
					i++;
				}
			}
			break;

		// 僅大寫字母
		case TYPE_UPPER_ONLY:
			while (i < length) {
				int t = r.nextInt(91);
				if ((t >= 65) && (exChars == null || exChars.indexOf((char) t) < 0)) {
					code.append((char) t);
					i++;
				}
			}
			break;

		// 僅小寫字母
		case TYPE_LOWER_ONLY:
			while (i < length) {
				int t = r.nextInt(123);
				if ((t >= 97) && (exChars == null || exChars.indexOf((char) t) < 0)) {
					code.append((char) t);
					i++;
				}
			}
			break;

		}

		return code.toString();
	}

	/**
	 * 已有驗證碼,生成驗證碼圖片
	 * 
	 * @param textCode
	 *            文字驗證碼
	 * @param width
	 *            圖片寬度
	 * @param height
	 *            圖片高度
	 * @param interLine
	 *            圖片中干擾線的條數
	 * @param randomLocation
	 *            每個字元的高低位置是否隨機
	 * @param backColor
	 *            圖片顏色,若為null,則採用隨機顏色
	 * @param foreColor
	 *            字型顏色,若為null,則採用隨機顏色
	 * @param lineColor
	 *            干擾線顏色,若為null,則採用隨機顏色
	 * @return 圖片快取物件
	 */
	public static BufferedImage generateImageCode(String textCode, int width, int height, int interLine,
			boolean randomLocation, Color backColor, Color foreColor, Color lineColor) {

		BufferedImage bim = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
		Graphics g = bim.getGraphics();

		// 畫背景圖
		g.setColor(backColor == null ? getRandomColor() : backColor);
		g.fillRect(0, 0, width, height);

		// 畫干擾線
		Random r = new Random();
		if (interLine > 0) {

			int x = 0, y = 0, x1 = width, y1 = 0;
			for (int i = 0; i < interLine; i++) {
				g.setColor(lineColor == null ? getRandomColor() : lineColor);
				y = r.nextInt(height);
				y1 = r.nextInt(height);

				g.drawLine(x, y, x1, y1);
			}
		}

		// 寫驗證碼

		// g.setColor(getRandomColor());
		// g.setColor(isSimpleColor?Color.BLACK:Color.WHITE);

		// 字型大小為圖片高度的80%
		int fsize = (int) (height * 0.8);
		int fx = height - fsize;
		int fy = fsize;

		g.setFont(new Font("Default", Font.PLAIN, fsize));

		// 寫驗證碼字元
		for (int i = 0; i < textCode.length(); i++) {
			fy = randomLocation ? (int) ((Math.random() * 0.3 + 0.6) * height) : fy;// 每個字元高低是否隨機
			g.setColor(foreColor == null ? getRandomColor() : foreColor);
			g.drawString(textCode.charAt(i) + "", fx, fy);
			fx += fsize * 0.9;
		}

		g.dispose();

		return bim;
	}

	/**
	 * 生成圖片驗證碼
	 * 
	 * @param type
	 *            驗證碼型別,參見本類的靜態屬性
	 * @param length
	 *            驗證碼字元長度,大於0的整數
	 * @param exChars
	 *            需排除的特殊字元
	 * @param width
	 *            圖片寬度
	 * @param height
	 *            圖片高度
	 * @param interLine
	 *            圖片中干擾線的條數
	 * @param randomLocation
	 *            每個字元的高低位置是否隨機
	 * @param backColor
	 *            圖片顏色,若為null,則採用隨機顏色
	 * @param foreColor
	 *            字型顏色,若為null,則採用隨機顏色
	 * @param lineColor
	 *            干擾線顏色,若為null,則採用隨機顏色
	 * @return 圖片快取物件
	 */
	public static BufferedImage generateImageCode(int type, int length, String exChars, int width, int height,
			int interLine, boolean randomLocation, Color backColor, Color foreColor, Color lineColor) {

		String textCode = generateTextCode(type, length, exChars);
		BufferedImage bim = generateImageCode(textCode, width, height, interLine, randomLocation, backColor, foreColor,
				lineColor);

		return bim;
	}

	/**
	 * 產生隨機顏色
	 * 
	 * @return
	 */
	private static Color getRandomColor() {
		Random r = new Random();
		Color c = new Color(r.nextInt(255), r.nextInt(255), r.nextInt(255));
		return c;
	}

	 public  void validateCode(HttpServletRequest request, HttpServletResponse response) throws IOException {
		 	System.setProperty("java.awt.headless","true");
	        response.setHeader("Cache-Control", "no-cache");
	        String verifyCode = ValidateCode.generateTextCode(ValidateCode.TYPE_NUM_LOWER, 4, null);
	        request.getSession().setAttribute("validateCode", verifyCode);
	        response.setContentType("image/jpeg");
	        BufferedImage bim = ValidateCode.generateImageCode(verifyCode, 90, 30, 5, true, Color.WHITE, Color.BLUE, null);
	        ImageIO.write(bim, "JPEG", response.getOutputStream());
	    }
}

controller

public void validateCodeVue(HttpServletRequest request, HttpServletResponse response,
                                 String code_key) throws IOException {
        response.setHeader("Cache-Control", "no-cache");

        System.setProperty("java.awt.headless", "true");
        String verifyCode = ValidateCode.generateTextCode(ValidateCode.TYPE_NUM_LOWER, 4, null);
        //request.getSession().setAttribute("validateCode", verifyCode);
        LogUtils.info("獲取圖片驗證碼************code=" + verifyCode);
        String key = redisDBService.GET(code_key);
        if (key != null) {
            redisDBService.DEL(code_key);
        }
        redisDBService.SET(code_key, verifyCode, 60 * 5);

        response.setContentType("image/jpeg");
        BufferedImage bim = ValidateCode.generateImageCode(verifyCode, 90, 30, 5, true, Color.WHITE, Color.BLUE, null);
        // 刪除以前的
        request.getSession().removeAttribute("verifyCode");
        request.getSession().setAttribute("verifyCode", verifyCode.toLowerCase());
        ImageIO.write(bim, "JPG", response.getOutputStream());


    }