Java implementation verification code specific code
- 2020-04-01 02:34:55
- OfStack
Here I used struts2 to simulate a login function to validate the Java implementation of the captcha function.
Java implementation of verification code steps:
1, create RandomImageGenerator. Java classes, the class implementation captcha images generated
2. Create a servlet class, randomimageservlet.java, output the generated verification code to the page
3. Create an Action class, LoginAction. Java, to control login
4. Configure struts.xml as a web.xml file
5. Write pages
The concrete implementation is expressed in code
1, create RandomImageGenerator. Java classes
package com.tenghu.code;
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.io.OutputStream;
import java.util.Random;
import javax.imageio.ImageIO;
public class RandomImageGenerator {
//Create a Random object
static Random random=new Random();
//Randomly generated containing captcha strings
public static String random(int num){
//Seed initialization
String[] str={"0","1","2","3","4","5","6","7","8","9",
"a","b","c","d","e","f","g","h","i","j",
"k","l","m","n","p","q","r","s","t"};
int number=str.length;
//Receive random character
String text = "";
//Randomly produces a four-character string
for(int i=0;i<num;i++){
text+=str[random.nextInt(number)];
}
return text;
}
private static Color getRandColor() {
Random random = new Random();
Color color[] = new Color[10];
color[0] = new Color(32, 158, 25);
color[1] = new Color(218, 42, 19);
color[2] = new Color(31, 75, 208);
color[3] = new Color(0, 102, 182);
color[4] = new Color(171, 0, 85);
return color[random.nextInt(5)];
}
private static Font getFont() {
Random random = new Random();
Font font[] = new Font[5];
font[0] = new Font("Ravie", Font.BOLD, 30);
font[1] = new Font("Antique Olive Compact", Font.BOLD, 30);
font[2] = new Font("Forte", Font.BOLD, 30);
font[3] = new Font("Wide Latin", Font.BOLD, 30);
font[4] = new Font("Gill Sans Ultra Bold", Font.BOLD, 30);
return font[random.nextInt(5)];
}
public static void render(String randomStr,OutputStream out,int width,int height) throws IOException{
//Create an image in memory
BufferedImage bi=new BufferedImage(width, height, BufferedImage.TYPE_BYTE_INDEXED);
//Getting the graphics context
Graphics2D g=(Graphics2D) bi.getGraphics();
//Words border
g.setColor(Color.white);
g.fillRect(0, 0, width, height);
g.setFont(getFont());
g.setColor(Color.BLACK);
//Draw authentication codes, each at a different level
String str1[]=new String[randomStr.length()];
for(int i=0;i<str1.length;i++){
str1[i]=randomStr.substring(i,i+1);
int w=0;
int x=(i+1)%3;
//Generate a verification code character horizontal offset randomly
if(x==random.nextInt(7)){
w=30-random.nextInt(7);
}else{
w=30+random.nextInt(7);
}
//Randomly generated color
g.setColor(getRandColor());
g.drawString(str1[i], 20*i+10, w);
}
//Random interference points are generated and represented by different colors. The authentication code of the image is not easy to be detected by other programs
for(int i=0;i<100;i++){
int x=random.nextInt(width);
int y=random.nextInt(height);
Color color=new Color(random.nextInt(255), random.nextInt(255), random.nextInt(255));
//I'm going to draw random lines in different colors
g.setColor(color);
g.drawOval(x, y, 0, 0);
}
//Drew interference
for(int i=0;i<15;i++){
int x=random.nextInt(width);
int y=random.nextInt(height);
int x1=random.nextInt(width);
int y1=random.nextInt(height);
Color color=new Color(random.nextInt(255), random.nextInt(255), random.nextInt(255));
//Let me draw a bunch of random colors
g.setColor(color);
g.drawLine(x, y, x1, y1);
}
//The image effect
g.dispose();
//The output page
ImageIO.write(bi, "jpg", out);
}
public static void main(String[] args) throws FileNotFoundException, IOException {
//Get a random string
String randomStr=random(5);
System.out.println(randomStr);
//Generate images
render(randomStr, new FileOutputStream("D:\test.jpg"),130,40);
}
}
2. Create randomimageservlet.java
package com.tenghu.code.servlet;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import com.tenghu.code.RandomImageGenerator;
public class RandomImageServlet extends HttpServlet {
//Image width
int width=0;
//Picture height
int height=0;
//Number of random characters in the picture
int randomStrNum=0;
public void destroy() {
}
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doPost(request, response);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
request.setCharacterEncoding("UTF-8");
//Gets the HttpSession object
HttpSession session=request.getSession();
//Get a random string
String randomStr=RandomImageGenerator.random(randomStrNum);
if(null!=session){
//Set the parameters
session.setAttribute("randomStr", randomStr);
//Set the response type, the output picture client does not cache
response.setDateHeader("Expires", 1L);
response.setHeader("Cache-Control", "no-cache, no-store, max-age=0");
response.addHeader("Pragma", "no-cache");
response.setContentType("image/jpeg");
//Output to page
RandomImageGenerator.render(randomStr, response.getOutputStream(), width, height);
}
}
public void init() throws ServletException {
//To obtain the width
width=Integer.parseInt(this.getInitParameter("width"));
//To obtain high
height=Integer.parseInt(this.getInitParameter("height"));
//Get the number
randomStrNum=Integer.parseInt(this.getInitParameter("num"));
}
}
3. Create the LoginAction. Java class
package com.tenghu.code.action;
import java.io.ByteArrayInputStream;
import java.io.InputStream;
import com.opensymphony.xwork2.ActionContext;
import com.opensymphony.xwork2.ActionSupport;
public class LoginAction extends ActionSupport{
//The user name
private String userName;
//password
private String password;
//Verification code
private String code;
private InputStream inputStream;
public InputStream getResult(){
return inputStream;
}
//successful
public String success() throws Exception{
return SUCCESS;
}
//Test the login
public String testLogin() throws Exception{
// Get the picture Verification code
String randomStr=(String) ActionContext.getContext().getSession().get("randomStr");
if(code.trim().equalsIgnoreCase(randomStr)){
if("admin".equals(userName.trim())&&"admin".equals(password.trim())){
//successful
inputStream=new ByteArrayInputStream("1".getBytes("UTF-8"));
}else{
//The user name or password error
inputStream=new ByteArrayInputStream("2".getBytes("UTF-8"));
}
}else{
//Verification code error
inputStream=new ByteArrayInputStream("0".getBytes("UTF-8"));
}
return "result";
}
public String getUserName() {
return userName;
}
public void setUserName(String userName) {
this.userName = userName;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
public String getCode() {
return code;
}
public void setCode(String code) {
this.code = code;
}
}
4. Configure struts.xml and web.xml files
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE struts PUBLIC
"-//Apache Software Foundation//DTD Struts Configuration 2.3//EN"
"http://struts.apache.org/dtds/struts-2.3.dtd">
<struts>
<package name="installs" extends="struts-default">
<action name="login" class="com.tenghu.code.action.LoginAction">
<!-- Login to success.jsp page -->
<result name="success">success.jsp</result>
<!-- Login validation returns the data -->
<result name="result" type="stream">
<param name="contentType">text/html</param>
<param name="inputName">result</param>
</result>
</action>
</package>
</struts>
<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5"
xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
<servlet>
<description>This is the description of my J2EE component</description>
<display-name>This is the display name of my J2EE component</display-name>
<servlet-name>RandomImageServlet</servlet-name>
<servlet-class>com.tenghu.code.servlet.RandomImageServlet</servlet-class>
<!-- Initializes the image width -->
<init-param>
<param-name>width</param-name>
<param-value>130</param-value>
</init-param>
<!-- Initializes the image height -->
<init-param>
<param-name>height</param-name>
<param-value>40</param-value>
</init-param>
<!-- Initializes the number of random images -->
<init-param>
<param-name>num</param-name>
<param-value>4</param-value>
</init-param>
</servlet>
<servlet-mapping>
<servlet-name>RandomImageServlet</servlet-name>
<url-pattern>/verification.do</url-pattern>
</servlet-mapping>
<!-- configuration struts Core filter -->
<filter>
<filter-name>struts2</filter-name>
<filter-class>org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>struts2</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
</web-app>
5. Write the test page
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>My JSP 'index.jsp' starting page</title>
<script type="text/javascript" src="js/jquery-1.10.2.min.js"></script>
<script type="text/javascript" src="js/jquery.form.js"></script>
<script type="text/javascript">
$(document).ready(function(){
CODE.initCode();
//Validate the input
function checkInput(){
if($('#userName').val()==''){
alert(' Username cannot be empty! ');
return false;
}
if($('#password').val()==''){
alert(' Password cannot be empty! ');
return false;
}
if($('#code').val()==''){
alert(' Verification code cannot be empty! ');
return false;
}
return true;
}
//Click on the button
$('#btn').click(function(){
if(checkInput()==true){
$('#login_request').ajaxSubmit({
url:'login!testLogin',
cache:false,
type:'POST',
success:function(data){
if(data==0){
alert(' Verification code error! ');
//Change the verification code
CODE.initCode();
}else if(data==1){
alert(' Login successful! ');
//Submit to the login success page
$('#login_request')[0].submit();
}else if(data==2){
alert(' Wrong username or password! ');
//Change the verification code
CODE.initCode();
}
},
error:function(e){
alert(' Make a mistake! ');
}
});
}
});
});
var CODE={
//Initialize the captcha
initCode:function(){
$("#code_img").attr("src","verification.do?rmd="+new Date().getTime())//If you need to click on the picture to change the content of the picture, you must add the time rub
.click(function(){
$(this).attr("src","verification.do?rmd="+new Date().getTime());
});
}};
</script>
</head>
<body>
<form action="login!success" id="login_request" method="post">
UserName:<input type="text" id="userName" name="userName"/><br/>
Password:<input type="password" id="password" name="password"/><br>
Verification_Code:<input type="text" id="code" name="code"/><img id="code_img" style="position:relative;top:8px;height:25px"><br>
<input type="button" id="btn" value=" The login "/>
</form>
</body>
</html>
The success page is partially posted, just a paragraph of text
Display results:
< img border = 0 SRC = "/ / files.jb51.net/file_images/article/201312/20131212163007968.jpg" >