/**
 * 获取验证码
 * @param model
 * @param request
 * @param response
 * @param session
 */
@ResponseBody
@RequestMapping(value = "/getCaptcha")
public void verificationCode(Map<String, Object> model,
					HttpServletRequest request, HttpServletResponse response,HttpSession session) {
		StringBuffer randBuffer = new StringBuffer();
		for (Integer i = 1; i <= 4; i++) {
			randBuffer.append(new Random().nextInt(10));
		}
		String rand = randBuffer.toString();
		response.setHeader("Cache-Control", "no-cache");
		response.setHeader("Cache-Control", "no-store");
		response.setDateHeader("Expires", 0L); //设置验证码保存的时间
		response.setHeader("Pragma", "no-cache");
		session.setAttribute("vcode", rand); //记住验证码
		try {
			createCodeUtil vcodeService = new createCodeUtil();
			ImageIO.write((RenderedImage) vcodeService.drawRandNumber(rand),
							"JPEG", response.getOutputStream());
		} catch (IOException e) {
			e.printStackTrace();
		}
}

 工具类

package com.test.util;

import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.Serializable;
import java.util.Random;

public class createCodeUtil implements Serializable{

	private int width = 40;
	private int height = 20;
	private String fontName = "Times New Roman";
	private int fontSize = 14;
	private static BufferedImage image = new BufferedImage(40, 20, 1);

	/* (non-Javadoc)
	 * @see com.baoz.zhouzhou.service.impl.IVcodeService#drawRandNumber(java.lang.String)
	 */
	public synchronized Image drawRandNumber(String rand) {
		Graphics g = image.getGraphics();
		refreshBgColor(g);
		g.setFont(new Font(fontName, 0, fontSize));
		g.setColor(getRandColor(0, 120));
		g.drawString(rand, 6, 16);
		g.dispose();
		return image;
	}

	private static Random RANDOM = new Random();

	private void refreshBgColor(Graphics g) {
		g.fillRect(0, 0, width, height);
		g.setColor(getRandColor(160, 200));
		for (int i = 0; i < 100; i++) {
			int x = RANDOM.nextInt(width);
			int y = RANDOM.nextInt(height);
			int xl = RANDOM.nextInt(12);
			int yl = RANDOM.nextInt(12);
//			g.drawLine(x, y, x + xl, y + yl);
		}

	}

	private 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);
	}

	public void setFontName(String fontName) {
		this.fontName = fontName;
	}

	public void setFontSize(int fontSize) {
		this.fontSize = fontSize;
	}

	public void setHeight(int height) {
		this.height = height;
		image = new BufferedImage(width, height, 1);
	}

	public void setWidth(int width) {
		this.width = width;
		image = new BufferedImage(width, height, 1);
	}

	public static void main(String[] args) {
	}
}

最终效果

前言

利用java语言基础语句生成所需要的验证码

一、Random随机生成数方法生成验证码

1.代码+详细注释：

package String类常用API;

import java.util.ArrayList;
import java.util.Random;

public class 验证码的几种生成方法 {
    public static void main(String[] args) {
        //1，用随机生成数方法，生成验证码
        Random yzm = new Random();                          //定义一个随机生成数技术，用来生成随机数

        String yzm2 = "";                                   //定义一个空的Atring变量用来接收生成的验证码

        for (int i = 0; i < 5; i++) {                       //循环5次每次生成一位，5位验证码

        int a = yzm.nextInt(3);                             //验证码包括数字、大小写字母组成
        switch(a){                                          //a:    0       1       2
            case 0:                                         //      数字   小写字母   大写字母
                char s=(char)(yzm.nextInt(26)+65);
                yzm2 = yzm2 + s;
                break;
            case 1:
                char s1=(char)(yzm.nextInt(26)+97);
                yzm2 = yzm2 + s1;
                break;
            case 2:
                int s2=yzm.nextInt(10);
                yzm2 = yzm2 + s2;
                break;
        }
        }
        System.out.println("用随机生成数方法，生成的验证码:"+yzm2);
}
}

2 、运行结果：

​

二、用String常用API-charAit生成验证码

1.代码+详细注释：

package String类常用API;

import java.util.ArrayList;
import java.util.Random;

public class 验证码的几种生成方法 {
    public static void main(String[] args) {
        Random yzm = new Random();                          //定义一个随机生成数技术，用来生成随机数
//2，用String常用API-charAit生成验证码
        String yzm1 = "1234567890abcdefghijklmnopqrstuvwxwzABCDEFGHIJKLMNOPQRSTUVWXYZ";//定义一个String变量存放需要的数据，一共58位
        String yzm3 = "";//定义一个空的Atring变量用来接收生成的验证码
        for (int i = 0; i < 5; i++) {
            int a = yzm.nextInt(58);//随机生成0-57之间的数，提供索引位置
            yzm3+=yzm1.charAt(a);//用get 和提供的索引找到相应位置的数据给变量
        }
        System.out.println("用String常用API-charAit生成的验证码为:"+yzm3);


    }
}

2.运行结果

                ​

总结

以上就是今天要讲的内容，本文仅仅简单介绍了用java语言生成验证码的两种方法，String-charAit方法较为易懂，利用索引获取该位置字符接到空字符串完成验证码的生成，Random随机生成数方法生成验证码则是利用switch语句完成验证码生成。

在看崔老师的javaweb视频，第十二节课，看了源代码，自己动手写了写，有些地方和老师给的源码不同，比如获取字体那块，老师返回的是Color类型(直接设置了font,style,size)，我返回的是字体名字(String)

附上自己写的源代码

VerifyCode.java

package cn.edou.image;

import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.Random;

import javax.imageio.ImageIO;

public class VerifyCode {
	//定义一些变量
	private int x = 200;
	private int y = 80;
	private int fontSize = 70;
	private StringBuilder sb = new StringBuilder();
	private Random random = new Random();
	private Color bgColor = new Color(255,255,255);
	private String[] fontsName = {"宋体", "华文楷体", "黑体", "华文新魏", "华文隶书", "微软雅黑", "楷体_GB2312"};
	private String codes = "23456789abcdefghjklmnopqrstuvwxyzABCDEFGHJKLMNOPQRSTUVWXYZ";
	//获取随机的字体
	private String getFont(){
		int index = random.nextInt(fontsName.length);
		String fontName = fontsName[index];
		return fontName;
	}
	//获取字母
	private String getChar(){
		int index = random.nextInt(codes.length());
		String ch = codes.charAt(index)+"";
		return ch;
	}
	//获取颜色
	private Color getColor(){
		int red = random.nextInt(150);
		int green = random.nextInt(150);
		int blue = random.nextInt(150);
		return new Color(red,green,blue);
	}
	//设置缓冲区
	private BufferedImage getBufferedImage(){
		BufferedImage bi = new BufferedImage(x,y,BufferedImage.TYPE_INT_RGB);
		Graphics2D pen = (Graphics2D)bi.getGraphics();
		pen.setColor(this.bgColor);
		pen.fillRect(0,0,x,y);
		return bi;
	}
	//给缓冲区添加字符串,添加干扰线
	private BufferedImage addCharAndLine(){
		BufferedImage bi = getBufferedImage();
		Graphics2D pen = (Graphics2D)bi.getGraphics();
		for(int i=0;i<4;i++){
		String font = getFont();
		int style = random.nextInt(4);
		pen.setColor(getColor());
		pen.setFont(new Font(font,style,fontSize));
	    String s = getChar();
	    sb.append(s);
		pen.drawString(s, 10+i*50, 65);
		}
		int lineNumber = 3;
		pen.setColor(Color.BLUE);
//		pen.setStroke(new BasicStroke(1.5F));
		pen.setStroke(new BasicStroke(1.5F,BasicStroke.CAP_ROUND,BasicStroke.JOIN_MITER));
		for(int i=0;i<lineNumber;i++){
			int x1 = random.nextInt(x);
			int y1 = random.nextInt(y);
			int x2 = random.nextInt(x);
			int y2 = random.nextInt(y);
			pen.drawLine(x1, y1, x2, y2);
		}
		return bi;
	}
	//获取验证码的值
	public String getText(){
		return sb.toString();
	}
	//获取一张验证码图片
	public BufferedImage getImage(){
		return addCharAndLine();
	}
	//输出图片
	public void outputImage(BufferedImage bi,String imageName){
		String path = "D:\\JavaWebExercise\\day12\\"+imageName+".jpg";
		try {
			ImageIO.write(bi, "JPEG", new FileOutputStream(path));
		} catch (FileNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}

}

附上老师的源码

package cn.itcast.image;

import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.OutputStream;
import java.util.Random;

import javax.imageio.ImageIO;

public class VerifyCode {
	private int w = 70;
	private int h = 35;
 	private Random r = new Random();
 	// {"宋体", "华文楷体", "黑体", "华文新魏", "华文隶书", "微软雅黑", "楷体_GB2312"}
	private String[] fontNames  = {"宋体", "华文楷体", "黑体", "微软雅黑", "楷体_GB2312"};
	// 可选字符
	private String codes  = "23456789abcdefghjkmnopqrstuvwxyzABCDEFGHJKMNPQRSTUVWXYZ";
	// 背景色
	private Color bgColor  = new Color(255, 255, 255);
	// 验证码上的文本
	private String text ;
	
	// 生成随机的颜色
	private Color randomColor () {
		int red = r.nextInt(150);
		int green = r.nextInt(150);
		int blue = r.nextInt(150);
		return new Color(red, green, blue);
	}
	
	// 生成随机的字体
	private Font randomFont () {
		int index = r.nextInt(fontNames.length);
		String fontName = fontNames[index];//生成随机的字体名称
		int style = r.nextInt(4);//生成随机的样式, 0(无样式), 1(粗体), 2(斜体), 3(粗体+斜体)
		int size = r.nextInt(5) + 24; //生成随机字号, 24 ~ 28
		return new Font(fontName, style, size);
	}
	
	// 画干扰线
	private void drawLine (BufferedImage image) {
		int num  = 3;//一共画3条
		Graphics2D g2 = (Graphics2D)image.getGraphics();
		for(int i = 0; i < num; i++) {//生成两个点的坐标，即4个值
			int x1 = r.nextInt(w);
			int y1 = r.nextInt(h);
			int x2 = r.nextInt(w);
			int y2 = r.nextInt(h); 
			g2.setStroke(new BasicStroke(1.5F)); 
			g2.setColor(Color.BLUE); //干扰线是蓝色
			g2.drawLine(x1, y1, x2, y2);//画线
		}
	}
	
	// 随机生成一个字符
	private char randomChar () {
		int index = r.nextInt(codes.length());
		return codes.charAt(index);
	}
	
	// 创建BufferedImage
	private BufferedImage createImage () {
		BufferedImage image = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB); 
		Graphics2D g2 = (Graphics2D)image.getGraphics(); 
		g2.setColor(this.bgColor);
		g2.fillRect(0, 0, w, h);
 		return image;
	}
	
	// 调用这个方法得到验证码
	public BufferedImage getImage () {
		BufferedImage image = createImage();//创建图片缓冲区 
		Graphics2D g2 = (Graphics2D)image.getGraphics();//得到绘制环境
		StringBuilder sb = new StringBuilder();//用来装载生成的验证码文本
		// 向图片中画4个字符
		for(int i = 0; i < 4; i++)  {//循环四次，每次生成一个字符
			String s = randomChar() + "";//随机生成一个字母 
			sb.append(s); //把字母添加到sb中
			float x = i * 1.0F * w / 4; //设置当前字符的x轴坐标
			g2.setFont(randomFont()); //设置随机字体
			g2.setColor(randomColor()); //设置随机颜色
			g2.drawString(s, x, h-5); //画图
		}
		this.text = sb.toString(); //把生成的字符串赋给了this.text
		drawLine(image); //添加干扰线
		return image;		
	}
	
	// 返回验证码图片上的文本
	public String getText () {
		return text;
	}
	
	// 保存图片到指定的输出流
	public static void output (BufferedImage image, OutputStream out) 
				throws IOException {
		ImageIO.write(image, "JPEG", out);
	}
}

想生成的话可以创建一个java文件来调用其中的方法，最后输出到指定的目录，在这里我指定的是D盘符，文件名自己给出，不用给后缀（第一个代码）

最后给出一个测试类，大家看看效果

@Test
	public void testVerifyCode(){
		VerifyCode vc = new VerifyCode();
		BufferedImage bi = vc.getImage();
		vc.outputImage(bi, "test2");
		System.out.println(vc.getText());
	}

最后一张图片是没有任何效果的，可以无视