java绘图相关类

验证码工具类

package dt2008.util;

import javax.imageio.ImageIO;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import java.awt.*;

import java.awt.image.BufferedImage;

import java.io.IOException;

import java.util.Random;

/**

* 验证码工具类

*/

public class RandomValidateCodeUtil {

//定义随机类

private Random random = new Random();

public void code(HttpServletRequest request, HttpServletResponse response){

//1.创建缓存图片类

//构造方法：new BufferedImage(int width,int height,int model)

BufferedImage image = new BufferedImage(150,50,BufferedImage.TYPE_INT_RGB);

//2.获取画笔

Graphics g = image.getGraphics();

//3.设置画笔颜色

g.setColor(Color.white);//白色

//4.填充矩形

//g.fillRect(x,y,width,height); x,y 起点的坐标，width矩形宽度，height矩形的高度

g.fillRect(0,0,150,50);

//5.画矩形边框

//设置画笔颜色(边框的颜色)

g.setColor(Color.blue);//蓝色

//画边框的语法：g.drawRect(x,y,width,height); x,y 起点的坐标，width边框宽度，height边框的高度

g.drawRect(1,1,147,47);

//6.画4条干扰线

//画直线语法：g.drawLine(x1,y1,x2,y2); x1,y1 线的起点坐标，x2,y2先的终点坐标

for (int i = 0; i < 4; i++) {

//设置画笔为随机颜色

g.setColor(getRandomColor());

//随机获取2个点

int x1 = random.nextInt(147)+1;

int y1 = random.nextInt(47)+1;

int x2 = random.nextInt(147)+1;

int y2 = random.nextInt(47)+1;

//画直线

g.drawLine(x1,y1,x2,y2);

}

//7.画验证码字符串

String checkCodeScope = "qwertyupasdfghjkzxcvbnm";

//定义接收拼接随机获取到的验证码字符变量

StringBuilder checkCodeBuilder = new StringBuilder();

//循环随机获取4个验证码字符

for (int i = 0; i < 4; i++) {

//获取随机位置

int index = random.nextInt(checkCodeScope.length());

//根据位置获取字符

char c = checkCodeScope.charAt(index);

//checkCodeBuilder拼接获取的随机字符

checkCodeBuilder.append(c);

//设置画笔的字体

//字符构造方法：new Font(字体，样式，大小)

g.setFont(new Font("微软雅黑",Font.BOLD,20));

//将每个字符画到图片上

//语法：g.drawString(字符串,x,y);

g.drawString(c+"",30+i*30,30);

}

request.getSession().setAttribute("SESSION_CHECKCODE", checkCodeBuilder.toString());

//8.将验证码图片输出给浏览器

//输出缓存图片的语法：ImageIO.write(缓存图片,图片的格式,输出给浏览器的字节流);

try {

ImageIO.write(image,"png",response.getOutputStream());

} catch (IOException e) {

e.printStackTrace();

}

}

//获取随机的颜色

private Color getRandomColor(){

int r = random.nextInt(256);

int g = random.nextInt(256);

int b = random.nextInt(256);

//构造方法语法：new Color(int r,int g,int b) //由红、绿、蓝组成， 每个颜色值范围0~255

return new Color(r,g,b);

}

}

Controller(生成验证码)

package yingshi.web;

import org.slf4j.Logger;

import org.slf4j.LoggerFactory;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.web.bind.annotation.RequestMapping;

import org.springframework.web.bind.annotation.RequestMethod;

import org.springframework.web.bind.annotation.RequestParam;

import org.springframework.web.bind.annotation.RestController;

import yingshi.util.RandomValidateCodeUtil;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import javax.servlet.http.HttpSession;

import java.io.IOException;

/**

* 登录以及验证码

*/

@RestController

@RequestMapping("login/admin")

public class LoginController {

/**

* 生成验证码

*/

@RequestMapping("getVerify")

public void getVerify(HttpServletRequest request, HttpServletResponse response) {

RandomValidateCodeUtil randomValidateCodeUtil = new RandomValidateCodeUtil();

randomValidateCodeUtil.code(request, response);

}

}

这时，可以访问验证码了，可以在前端那写个js点击切换验证码

接下来就是校验验证码(注意：是分大小写的)

package yingshi.web;

import org.slf4j.Logger;

import org.slf4j.LoggerFactory;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.web.bind.annotation.RequestMapping;

import org.springframework.web.bind.annotation.RequestMethod;

import org.springframework.web.bind.annotation.RequestParam;

import org.springframework.web.bind.annotation.RestController;

import yingshi.util.RandomValidateCodeUtil;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import javax.servlet.http.HttpSession;

import java.io.IOException;

/**

* 登录以及验证码

*/

@RestController

@RequestMapping("login/admin")

public class LoginController {

/**

* 校验后台登录

*/

@RequestMapping("checkVerify")

public String checkVerify(String username, String password, String verifyInput, HttpServletRequest request, HttpServletResponse response) {

//验证码校验

//获取session中的验证码

String sessionCheckCode = (String) request.getSession().getAttribute("SESSION_CHECKCODE");

//判断验证码是否正确

if(!verifyInput.equals(sessionCheckCode)){

return "错误";

}else{

return "正确";

}

}

}

希望这篇文章对您有帮助！