小菜鸟写的，如有错误敬请指正。
先通过Maven构建系统配置好web服务，这边简单过一下
输入项目的名字与地址
这边GroupId的格式要是唯一的所以一般为域名的形式列例如：cn.edu.mju.project
选择Mavens中settings.xml的路径与库的路径，这边按自己电脑的安装情况而定
将pom.xml文件中信息更改如下：
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache/POM/4.0.0" xmlns:xsi="http://www.w3/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache/POM/4.0.0 http://maven.apache/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>cn.edu.mju</groupId>
<artifactId>Project2</artifactId>
<version>1.0-SNAPSHOT</version>
<packaging>war</packaging>
<name>Project2 Maven Webapp</name>
<!-- FIXME change it to the project's website -->
<url>http://www.example.com</url>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<maven.compiler.source>1.7</maven.compiler.source>
<maven.compiler.target>1.7</maven.compiler.target>
</properties>
<dependencies>
<!-- https://mvnrepository.com/artifact/javax.servlet/javax.servlet-api -->
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>javax.servlet-api</artifactId>
<version>3.1.0</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.11</version>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<finalName>Project2</finalName>
<pluginManagement><!-- lock down plugins versions to avoid using Maven defaults (may be moved to parent pom) -->
<plugins>
<plugin>
<groupId>org.mortbay.jetty</groupId>
<artifactId>jetty-maven-plugin</artifactId>
<configuration>
<webApp>
<contextPath>/test50</contextPath>
</webApp>
<connectors>
<connector implementation="org.eclipse.jetty.server.nio.SelectChannelConnector">
<port>8081</port>
<maxIdleTime>6000</maxIdleTime>
</connector>
</connectors>
</configuration>
</plugin>
<plugin>
<artifactId>maven-clean-plugin</artifactId>
<version>3.1.0</version>
</plugin>
<!-- see http://maven.apache.org/ref/current/maven-core/default-bindings.html#Plugin_bindings_for_war_packaging -->
<plugin>
<artifactId>maven-resources-plugin</artifactId>
<version>3.0.2</version>
</plugin>
<plugin>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.8.0</version>
</plugin>
<plugin>
<artifactId>maven-surefire-plugin</artifactId>
<version>2.22.1</version>
</plugin>
<plugin>
<artifactId>maven-war-plugin</artifactId>
<version>3.2.2</version>
</plugin>
<plugin>
<artifactId>maven-install-plugin</artifactId>
<version>2.5.2</version>
</plugin>
<plugin>
<artifactId>maven-deploy-plugin</artifactId>
<version>2.8.2</version>
</plugin>
</plugins>
</pluginManagement>
</build>
</project>
设置端口号8081，与空闲时间，例如：
则地址为：localhost:8081/test50/
代码文件
配置完web服务后，在main文件夹下创建java文件夹并右键Mark Directory as标记为Sources Root用来放置我们的代码文件，如下：
然后在java文件夹下新建一个cn.edu.mju.project2troller包，并创建一个LoginController类与CaptcheController类用来放置所需的代码文件
CaptcheController类代码如下👇
package cn.edu.mju.project2.comtroller;
import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.Random;
/**
* @Author xqs
* @Date 2020/4/7 20:26
* @Description 简单验证码的实现
*/
@WebServlet("/captcha")
public class CaptcheController extends HttpServlet {
private final int WIDTH = 130 ;
private final int HEIGHT = 60;
@Override
protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//禁止缓存，防止验证码过期
resp.setHeader("pragma", "no-cache");
resp.setHeader("cache-control", "no-cache");
resp.setHeader("Expires", "0");//过期时间设置为0，就是立马过期的意思
//申请内存空间
BufferedImage img = new BufferedImage(WIDTH, HEIGHT, BufferedImage.TYPE_INT_RGB);
//画笔
Graphics gg = img.getGraphics();
Graphics2D g = (Graphics2D) gg;//为了旋转功能
//设置背景颜色
g.setColor(Color.white);
//g.fillRect(0,0,100,60);
//设置背景大小
g.fillRect(0, 0, WIDTH, HEIGHT);
//设置干扰线
randomLine(80, g);
//设置干扰点
randomDrop(100, g);
//设置验证码
Random rd = new Random();
StringBuilder b = new StringBuilder();
//循环四次，四位
for (int i = 0; i < 4; i++) {
//字体固定，大小随机
g.setFont(new Font("name", Font.BOLD, rd.nextInt(20) + 25));
//设置验证码颜色，稍微深一点
g.setColor(getColor(50));
//调用randomString方法设置验证码个数
String code = randomString(1);
//设置每个验证码的坐标
int x = 30 * i;
int y = rd.nextInt(10) + 35;
//设置随机旋转角度
int revolve = rd.nextInt(10);
//设置随机顺时针或逆时针旋转
if (rd.nextBoolean()) revolve = -revolve;
//旋转,Math.toRadians角度转弧度
g.rotate(Math.toRadians(revolve), 5 + x, HEIGHT / 3);
//g.rotate(Math.toRadians(-revolve),65 , 30);
//设置验证码位置，x大往右，y大往下
g.drawString(code, 5 + x, y);
b.append(code);
}
//创建session对象，将验证码code 保存在session中
HttpSession session = req.getSession();
session.setAttribute("code", b.toString());
// 释放资源
g.dispose();
// 图片输出 ImageIO
ServletOutputStream out = resp.getOutputStream();
ImageIO.write(img, "JPEG", out);
try {
out.flush();
} catch (Exception ex) {
} finally {
out.close();
}
}
/**
* @Description 生成随机干扰
* @Param [count, g]
* @Return void
*/
//随机干扰点
public void randomDrop(int count, Graphics2D g) {
for (int i = 0; i < count; i++) {
Random rd = new Random();
int x = rd.nextInt(WIDTH);//产生小于WIDTH的随机整数
int y = rd.nextInt(HEIGHT);//产生小于HEIGHT的随机整数
g.setColor(getColor(0));//随机颜色
g.drawLine(x, y, x, y + 2);//绘制超短的线，看着是个点
}
}
//随机干扰线
public void randomLine(int count, Graphics2D g) {
for (int i = 0; i < count; i++) {
Random rd = new Random();
int xBegin = rd.nextInt(WIDTH);//产生小于WIDTH的随机整数，起始位置
int yBegin = rd.nextInt(HEIGHT);//产生小于HEIGHT的随机整数
int xEnd = rd.nextInt(xBegin + 50);//终点
int yEnd = rd.nextInt(yBegin + 30);
g.setColor(getColor(0));//随机颜色
g.drawLine(xBegin, yBegin, xEnd, yEnd);//绘制线条
}
}
/**
* @Description 生成随机验证码
* @Param 需要几位验证码
* @Return 随机生成的验证码
*/
//随机验证码
public String randomString(int count) {
StringBuilder builder = new StringBuilder();
String source = "ABCDEFGHJKLMNPQRSTUVWXYZ0123456789";
Random rnd = new Random();
for (int i = 0; i < count; i++) {
int pos = rnd.nextInt(source.length());
String s = source.substring(pos, pos + 1);
builder.append(s);//每位验证码之间加个空格
}
return builder.toString();
}
/**
* @Description 生成随机颜色值
* @Param a越大颜色越深
* @Return 随机的RGB颜色
*/
public Color getColor(int a) {
Random rd = new Random(); //Math.random()为生成0-1随机数
int r = rd.nextInt(256 - a);//rd.nextInt(256)为随机生成0-255随机数
int g = rd.nextInt(256 - a);
int b = rd.nextInt(256 - a);
return new Color(r, g, b);
}
}
LoginController类代码如下👇
package cn.edu.mju.project2.comtroller;
import cn.edu.mju.project2.utils.StrUtil;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;
//@Servlet("/login")
@WebServlet("/login")
public class LoginController extends HttpServlet {
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
String info = "Hello ";
StringBuilder stringBuilder = new StringBuilder();
stringBuilder.append("<font size = '20'>欢迎登陆</font>");
stringBuilder.append("<form action='' method = 'post'>");
stringBuilder.append("登陆名称：<input type='test' name='loginName' valus='' ><br>");
stringBuilder.append("登陆密码：<input type='password' name='loginPwd' valus='' ><br>");
stringBuilder.append("验 证 码 ：<input type='test' name='validCode' valus='' ><img src='./captcha' width ='100' height='60'><br>");
stringBuilder.append("<input type='submit' value='提交'>");
stringBuilder.append("</form>");
showMsg(resp, stringBuilder.toString());
}
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
String loginName = req.getParameter("loginName");
String loginPwd = req.getParameter("loginPwd");
String validCode = req.getParameter("validCode");
String saveCode = (String) req.getSession().getAttribute("code");//用强转不用tostring，否则会空指针异常
String msg = null;
if (StrUtil.isBank(loginName) && StrUtil.isBank(loginPwd)) {
msg = "<font size = '20'>请输入账号密码！</font>";
} else {
if (StrUtil.isBank(validCode)) {
msg = "<font size = '20'>请输入验证码！</font>";
} else {
if (validCode.equalsIgnoreCase(saveCode)) {//比较验证码，不区分大小写
//登陆名称是你的学号，密码是1234，那么显示下面的内容，否则，显示用户账户或密码错误
if ("5197101250".equals(loginName) && "1234".equals(loginPwd)) {
msg = "<font size = '20'>欢迎" + loginName + "登陆</font>";
} else {
msg = "<font size = '20'>账号或密码错误！</font>";
}
} else {
msg = "<font size = '20'>验证码错误！</font>";
}
}
}
showMsg(resp, msg);
}
private void showMsg(HttpServletResponse resp,String msg){
resp.setCharacterEncoding("utf-8");
try{
PrintWriter out = resp.getWriter();
out.println("<html>");
out.println("<meta charset=\"utf-8\">");
out.println("<header>");
out.println("<title>test</title>");
out.println("</header>");
out.println("<body>");
out.println(msg);
out.println("</body>");
out.println("</html>");
out.close();
}catch (Exception ex){
System.out.println(ex.getMessage());
}
}
}
strUtil类代码如下👇
这边创建一个utlis包放经常用到的功能类
package cn.edu.mju.project2.utils;
/**
* @Author xqs
* @Date 2020/4/7 16:33
* @Description 功能类
*/
public class StrUtil {
/**
* @Description 判断输入字符串是否为空
* @Param 要判断是否为空的字符串
* @Return boolean
*/
public static boolean isBank(String str) {
if (str == null || str.equals("")) {
return true;
} else {
return false;
}
}
}
最后运行效果如下👇
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