SSM带验证码登录

登陆的时候有的需要带验证码连同用户名密码一同发送到后台校验，用户名和密码的校验我这个demo里面就不处理了，为了突出验证码部分，所以直接看验证码的校验就可以,验证通过控制台打印“用户输入的验证码和图片生成的验证码相等，登陆成功”。

JSP页面代码

<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>














	

		

			
登录
		
		

			

				
				

					

					 
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Controller代码：注意的是，当访问登录界面的时候就会自动加载验证码图片，同时把验证码值存入session中，当我们处理登录逻辑的时候是通过前端输入的验证码值和从session中存储的图片中的验证码值来进行比较进行校验的。

package com.wonders.controller;

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.font.FontRenderContext;
import java.awt.geom.Rectangle2D;
import java.awt.image.BufferedImage;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.Random;

import javax.imageio.ImageIO;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.servlet.ModelAndView;

/**
 * 登录功能
 */
@Controller
@RequestMapping("/login")
public class LoginController {
	// http://localhost:8080/ssmmaven/login/showLoginView
	@RequestMapping("/showLoginView")
	public ModelAndView getIndex() {
		ModelAndView mv = new ModelAndView();
		mv.setViewName("login");
		return mv;
	}

	/**
	 * 获取验证码
	 * 
	 * @param response
	 * @param session
	 */
	@RequestMapping("/getVerifyCode")
	public void generate(HttpServletResponse response, HttpSession session) {
		ByteArrayOutputStream output = new ByteArrayOutputStream();
		String verifyCodeValue = drawImg(output);

		session.setAttribute("verifyCodeValue", verifyCodeValue);

		try {
			ServletOutputStream out = response.getOutputStream();
			output.writeTo(out);
		} catch (IOException e) {
			e.printStackTrace();
		}
	}

	/**
	 * 绘画验证码
	 * 
	 * @param output
	 * @return
	 */
	private String drawImg(ByteArrayOutputStream output) {
		String code = "";
		// 随机产生4个字符
		for (int i = 0; i < 4; i++) {
			code += randomChar();
		}
		int width = 70;
		int height = 25;
		BufferedImage bi = new BufferedImage(width, height,
				BufferedImage.TYPE_3BYTE_BGR);
		Font font = new Font("Times New Roman", Font.PLAIN, 20);
		// 调用Graphics2D绘画验证码
		Graphics2D g = bi.createGraphics();
		g.setFont(font);
		Color color = new Color(66, 2, 82);
		g.setColor(color);
		g.setBackground(new Color(226, 226, 240));
		g.clearRect(0, 0, width, height);
		FontRenderContext context = g.getFontRenderContext();
		Rectangle2D bounds = font.getStringBounds(code, context);
		double x = (width - bounds.getWidth()) / 2;
		double y = (height - bounds.getHeight()) / 2;
		double ascent = bounds.getY();
		double baseY = y - ascent;
		g.drawString(code, (int) x, (int) baseY);
		g.dispose();
		try {
			ImageIO.write(bi, "jpg", output);
		} catch (IOException e) {
			e.printStackTrace();
		}
		return code;
	}

	/**
	 * 随机参数一个字符
	 * 
	 * @return
	 */
	private char randomChar() {
		Random r = new Random();
		String s = "ABCDEFGHJKLMNPRSTUVWXYZ0123456789";
		return s.charAt(r.nextInt(s.length()));
	}

	/**
	 * 登录逻辑
	 */
	@RequestMapping("/login")
	public void login(HttpServletRequest request, HttpSession session) {
		String inputVerifyCode=request.getParameter("verifyCode");
		System.out.println("用户输入的验证码值------>"
				+ inputVerifyCode);
		String verifyCodeValue=(String) session.getAttribute("verifyCodeValue");
		System.out.println("Session中的验证码值------>"
				+ verifyCodeValue);
		if(verifyCodeValue.equals(inputVerifyCode.toUpperCase())){
			System.out.println("用户输入的验证码和图片生成的验证码相等，登陆成功");
		}
	}
}

效果如下：