如果想用框架来实现验证码,可以看我的另外一篇:
kaptcha 框架的使用很简单的。新手必备。
http://www.zzvips.com/article/171694.html
一、效果图
二、实现代码
第一步:先建一个 randomvalidatecode.java 作为工具类。把下面的代码直接复制粘贴即可。
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package com.utils;
import java.awt.color;
import java.awt.font;
import java.awt.graphics;
import java.awt.image.bufferedimage;
import java.util.random;
import javax.imageio.imageio;
import javax.servlet.http.httpservletrequest;
import javax.servlet.http.httpservletresponse;
import javax.servlet.http.httpsession;
public class randomvalidatecode {
public static final string randomcodekey = "randomcode_key" ; //放到session中的key
private random random = new random();
private string randstring = "0123456789abcdefghijklmnopqrstuvwxyz" ; //随机产生的字符串
private int width = 80 ; //图片宽
private int height = 26 ; //图片高
private int linesize = 40 ; //干扰线数量
private int stringnum = 4 ; //随机产生字符数量
/**
* 生成随机图片
*/
public void getrandcode(httpservletrequest request,
httpservletresponse response) {
httpsession session = request.getsession();
//bufferedimage类是具有缓冲区的image类,image类是用于描述图像信息的类
bufferedimage image = new bufferedimage(width,height,bufferedimage.type_int_bgr);
//产生image对象的graphics对象,改对象可以在图像上进行各种绘制操作
graphics g = image.getgraphics();
g.fillrect( 0 , 0 , width, height);
g.setfont( new font( "times new roman" ,font.roman_baseline, 18 ));
g.setcolor(getrandcolor( 160 , 200 ));
//绘制干扰线
for ( int i= 0 ;i<=linesize;i++){
drowline(g);
}
//绘制随机字符
string randomstring = "" ;
for ( int i= 1 ;i<=stringnum;i++){
randomstring=drowstring(g,randomstring,i);
}
session.removeattribute(randomcodekey);
session.setattribute(randomcodekey, randomstring);
g.dispose();
try {
//将内存中的图片通过流动形式输出到客户端
imageio.write(image, "jpeg" , response.getoutputstream());
} catch (exception e) {
e.printstacktrace();
}
}
/*
* 获得字体
*/
private font getfont(){
return new font("fixedsys",font.center_baseline,18);
}
/*
* 获得颜色
*/
private color getrandcolor(int fc,int bc){
if(fc > 255)
fc = 255;
if(bc > 255)
bc = 255;
int r = fc + random.nextint(bc-fc-16);
int g = fc + random.nextint(bc-fc-14);
int b = fc + random.nextint(bc-fc-18);
return new color(r,g,b);
}
/*
* 绘制字符串
*/
private string drowstring(graphics g,string randomstring,int i){
g.setfont(getfont());
g.setcolor(new color(random.nextint(101),random.nextint(111),random.nextint(121)));
string rand = string.valueof(getrandomstring(random.nextint(randstring.length())));
randomstring +=rand;
g.translate(random.nextint(3), random.nextint(3));
g.drawstring(rand, 13*i, 16);
return randomstring;
}
/*
* 绘制干扰线
*/
private void drowline(graphics g){
int x = random.nextint(width);
int y = random.nextint(height);
int xl = random.nextint(13);
int yl = random.nextint(15);
g.drawline(x, y, x+xl, y+yl);
}
/*
* 获取随机的字符
*/
public string getrandomstring( int num){
return string.valueof(randstring.charat(num));
}
}
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第二步:在 controller 类写前端 ui 的接口
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/**
* 获取生成验证码显示到 ui 界面
* @param request
* @param response
* @throws servletexception
* @throws ioexception
*/
@requestmapping (value= "/checkcode" )
public void checkcode(httpservletrequest request, httpservletresponse response)
throws servletexception, ioexception {
//设置相应类型,告诉浏览器输出的内容为图片
response.setcontenttype( "image/jpeg" );
//设置响应头信息,告诉浏览器不要缓存此内容
response.setheader( "pragma" , "no-cache" );
response.setheader( "cache-control" , "no-cache" );
response.setdateheader( "expire" , 0 );
randomvalidatecode randomvalidatecode = new randomvalidatecode();
try {
randomvalidatecode.getrandcode(request, response); //输出图片方法
} catch (exception e) {
e.printstacktrace();
}
}
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第三步:jsp 页面获取验证码
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<img src= "checkcode" alt= "" width= "100" height= "32" class = "passcode" style= "height:43px;cursor:pointer;" onclick= "this.src=this.src+'?'" >
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第四步:我的是在 ssm 环境下实现的,如果不是的话可以自己改写下。
总结
以上所述是小编给大家介绍的ssm 实现登录验证码功能,希望对大家有所帮助,如果大家有任何疑问请给我留言,小编会及时回复大家的。在此也非常感谢大家对服务器之家网站的支持!
原文链接:https://blog.csdn.net/weidong_y/article/details/80630383