第一种方式
代码语言：javascript
复制@WebServlet("/BufferImage")
public class BufferImage extends HttpServlet {
public static final int WIDTH = 120;//生成图片的宽度
public static final int HEIGHT = 30;//生成图片的高度
public static final int WORDS_NUMBER = 4;//验证码中字符的个数
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
// TODO Auto-generated method stub
this.doPost(req, resp);
}
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
req.setCharacterEncoding("utf-8");
resp.setContentType("text/html;charset=utf-8");
// TODO Auto-generated method stub
String createTypeFlag = req.getParameter("createTypeFlag");//接收客户端传递的createTypeFlag标识
//在内存中创建一张图片
BufferedImage bi = new BufferedImage(WIDTH,HEIGHT,BufferedImage.TYPE_3BYTE_BGR);
//得到图片
Graphics g = bi.getGraphics();
//设置图片的背景色
setBackGround(g);
//设置图片的边框
setBorder(g);
//在图片上画干扰线
drawRandomLine(g);
//在图片上放上随机字符
String randomString = this.drawRandomNum((Graphics2D)g, createTypeFlag);
System.out.println(randomString);
//将随机数存在session中
req.getSession().setAttribute("checkcode", randomString);
//设置响应头通知浏览器以图片的形式打开
resp.setContentType("image/jpeg");
//设置响应头控制浏览器不要缓存
resp.setDateHeader("expries", -1);
resp.setHeader("Cache-Control", "no-cache");
resp.setHeader("Pragma", "no-cache");
//将图片传给浏览器
ImageIO.write(bi, "jpg", resp.getOutputStream());
}
//设置图片背景色
//@param g
private void setBackGround(Graphics g) {
//设置颜色
g.setColor(Color.WHITE);
//填充区域
g.fillRect(0, 0, WIDTH, HEIGHT);
}
/*
* 设置图片的边框
* @param g
* */
private void setBorder(Graphics g) {
//设置边框颜色
g.setColor(Color.BLUE);
//边框区域
g.drawRect(1, 1, WIDTH - 2, HEIGHT -2);
}
/*
* 在图片上画随机线条
* @param g
* */
private void drawRandomLine(Graphics g) {
//设置颜色
g.setColor(Color.GREEN);
//设置线条个数并画线
for ( int i = 0 ; i < 7 ; i ) {
int x1 = new Random().nextInt(WIDTH);
int y1 = new Random().nextInt(HEIGHT);
int x2 = new Random().nextInt(WIDTH);
int y2 = new Random().nextInt(HEIGHT);
g.drawLine(x1, y1, x2, y2);
}
}
/*
* 在图片上画随机字符
* @param g
* @param createTypeFlag
* @return String
* */
private String drawRandomNum(Graphics g,String createTypeFlag) {
//设置颜色
g.setColor(Color.BLUE);
g.setFont(new Font("宋体",Font.BOLD,20));
//数字字母的组合
String baseNumLetter = "0123456789ABCDEFGHJKLMNOPQRSTUVWXYZ";
String baseNum = "0123456789";
String baseLetter = "ABCDEFGHJKLMNOPQRSTUVWXYZ";
if ( createTypeFlag != null && createTypeFlag.length() > 0 ) {
if( createTypeFlag.equals("nl") ) {
//截取数字和字母的组合
return createRandomChar((Graphics2D) g,baseNumLetter);
} else if ( createTypeFlag.equals("n") ) {
//截取数字的组合
return createRandomChar((Graphics2D) g,baseNum);
} else if ( createTypeFlag.equals("l") ) {
//截取字母的组合
return createRandomChar((Graphics2D) g,baseLetter);
}
} else {
//截取数字和字母的组合
return createRandomChar((Graphics2D) g,baseNumLetter);
}
return "";
}
/*
* 创建随机字符
* @param g
* @param baseChar
* @return String
* */
private String createRandomChar(Graphics2D g , String baseChar) {
StringBuffer b = new StringBuffer();
int x = 5;
String ch = "";
for ( int i = 0 ; i < WORDS_NUMBER ; i ) {
//设置字体的旋转角度
int degree = new Random().nextInt() % 30;
ch = baseChar.charAt(new Random().nextInt(baseChar.length())) "";
b.append(ch);
//正向角度
g.rotate(degree * Math.PI / 180 , x,20);
g.drawString(ch, x, 20);
//反向角度
g.rotate(-degree * Math.PI / 180 , x,20);
x =30;
}
return b.toString();
}
}
后端
代码语言：javascript
复制 @RequestMapping(value="/userLogin.do")
public void userLogin(String code,HttpSession session){
String cht=(String)session.getAttribute("checkcode");
if(code.equalsIgnoreCase(cht)){
System.out.println("验证码正确");
}
}
前端
代码语言：javascript
复制<form>
<img src="BufferImage" οnclick="this.src='BufferImage?' new Date().getTime()">看不清换一张<br><br>
验证码： <input type="text" id="verify" class="input-medium" placeholder="验证码">
<input type="submit" value="提交">
</form>
第二种方式（Spring Boot框架使用）
代码语言：javascript
复制package com.zhiyou.util;
import javax.imageio.ImageIO;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.util.Random;
public final class BufferImage {
// 验证码字符集
private static final char[] chars = {
'0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N',
'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z'};
// 字符数量
private static final int SIZE = 4;
// 干扰线数量
private static final int LINES = 8;
// 宽度
private static final int WIDTH = 100;
// 高度
private static final int HEIGHT = 32;
// 字体大小
private static final int FONT_SIZE = 25;
/**
* 生成随机验证码及图片
* 数组中[验证码，图片]
*/
public static Object[] createImage() {
StringBuffer sb = new StringBuffer();
// 1.创建空白图片
BufferedImage image = new BufferedImage(
WIDTH, HEIGHT, BufferedImage.TYPE_INT_RGB);
// 2.获取图片画笔
Graphics graphic = image.getGraphics();
// 3.设置画笔颜色
graphic.setColor(new Color(216, 172, 203, 241));
// 4.绘制矩形背景
graphic.fillRect(0, 0, WIDTH, HEIGHT);
// 5.画随机字符
Random ran = new Random();
for (int i = 0; i <SIZE; i ) {
// 取随机字符索引
int n = ran.nextInt(chars.length);
// 设置随机颜色
graphic.setColor(getRandomColor());
// 设置字体大小
graphic.setFont(new Font(
null, Font.BOLD Font.ITALIC, FONT_SIZE));
// 画字符
graphic.drawString(
chars[n] "", i * WIDTH / SIZE, HEIGHT/2 HEIGHT/8);
// 记录字符
sb.append(chars[n]);
}
// 6.画干扰线
for (int i = 0; i < LINES; i ) {
graphic.setColor(getRandomColor());
// 随机画线
graphic.drawLine(ran.nextInt(WIDTH), ran.nextInt(HEIGHT),
ran.nextInt(WIDTH), ran.nextInt(HEIGHT));
}
// 7.返回验证码和图片
return new Object[]{sb.toString(), image};
}
/**
* 随机取色
*/
public static Color getRandomColor() {
Random ran = new Random();
Color color = new Color(ran.nextInt(256),
ran.nextInt(256), ran.nextInt(256));
return color;
}
public static void main(String[] args) throws IOException {
Object[] objs = createImage();
BufferedImage image = (BufferedImage) objs[1];
OutputStream os = new FileOutputStream("src/main/resources/static/picture/eb1ccd3d99794795bc99553b0b762e73.gif");
ImageIO.write(image, "png", os);
os.close();
}
}
后台controller
代码语言：javascript
复制/* **********************************图片验证码************************************* */
@RequestMapping(value = "/BufferImage")
protected void createImg(HttpServletRequest req, HttpServletResponse res) throws ServletException, IOException {
//1.生成随机的验证码及图片
Object[] objs = BufferImage.createImage();
//2.将验证码存入session
String imgcode = (String) objs[0];
HttpSession session = req.getSession();
session.setAttribute("checkcode", imgcode);
//3.将图片输出给浏览器
BufferedImage img = (BufferedImage) objs[1];
res.setContentType("image/png");
//服务器自动创建输出流，目标指向浏览器
OutputStream os = res.getOutputStream();
ImageIO.write(img, "png", os);
os.close();
}
