项目需求：
1. 访问带有验证码的登录页面login.jsp
2. 用户输入用户名，密码以及验证码。
* 如果用户名和密码输入有误，跳转登录页面，提示:用户名或密码错误
* 如果验证码输入有误，跳转登录页面，提示：验证码错误
* 如果全部输入正确，则跳转到主页success.jsp，显示：用户名,欢迎您
准备工作：
1，数据库：
数据库最好不要用关键字哟！
create table `users` ( //创建表
`id` int (11),
`name` varchar (60),
`psw` varchar (60)
);
//添加数据
insert into `users` (`id`, `name`, `psw`) values('1','曹操','123456');
insert into `users` (`id`, `name`, `psw`) values('2','貂蝉','123456');
insert into `users` (`id`, `name`, `psw`) values('3','西施','123456');
insert into `users` (`id`, `name`, `psw`) values('4','王昭君','root');
如果感觉麻烦，也可以用图形化界面创建哟！
2，需要导入的包有：
（注意包的结构哟，必须是在WEB-INF包下的lib文件夹下，自己要创建lib文件夹哟）
这里注意一下，我的项目结构有点乱，红框框中的是这个项目的结构，你们做的时候，要注意一下路径哟：
代码展示：
login.jsp中代码：
<body>
<h3><%=
request.getAttribute("msg")==null?"":request.getAttribute("msg")
%></h3>
<form action="/wang/login01" method="post">
姓名: <input type="text" name="name"> <br>
密码: <input type="password" name="psw"> <br>
验证码： <input type="text" name="code"> <img src="/wang/login01" alt=""> <br>
<input type="checkbox" name="remember" value="yes">7天免登录 <br>
<input type="submit" value="登录">
</form>
</body>
success.jsp页面中代码：
<body>
<%
Object user = session.getAttribute("user");
if (user==null){
//如果没有登陆，还访问当前页面，重定向去登陆页面
response.sendRedirect("/wang/users/login.jsp");
}
%>
<h2>
<%=session.getAttribute("name")%>,欢迎您！
</h2>
</body>
druid.properties中的代码：
driverClassName=com.mysql.cj.jdbc.Driver
url=jdbc:mysql://localhost:3306/long?useSSL=false&serverTimezone=UTC
username=root
password=123456
util工具类：
public class JdbcUtil {
public static DataSource getDataSource(){
Properties prop = new Properties();
DataSource ds=null;
try {
prop.load(new FileInputStream("D:\\IDEA_HOME_SERVLET\\day18-cookie\\src\\druid.properties"));
//注意这里的路径，可以用相对路径，但是我感觉比较麻烦，就用的绝对路径
ds = DruidDataSourceFactory.createDataSource(prop);
} catch (Exception e) {
e.printStackTrace();
}
return ds;
}
}
GenerateCode工具类：
用来生成验证码图片的，可以不用打，直接复制这个类到工具包下
public class GenerateCode {
//使用到Algerian字体，系统里没有的话需要安装字体，字体只显示大写，去掉了1,0,i,o几个容易混淆的字符
public static final String VERIFY_CODES = "23456789ABCDEFGHJKLMNPQRSTUVWXYZ";
private static Random random = new Random();
/**
* 使用系统默认字符源生成验证码
*
* @param verifySize 验证码长度
* @return
*/
public static String generateVerifyCode(int verifySize) {
return generateVerifyCode(verifySize, VERIFY_CODES);
}
/**
* 使用指定源生成验证码
*
* @param verifySize 验证码长度
* @param sources 验证码字符源
* @return
*/
public static String generateVerifyCode(int verifySize, String sources) {
if (sources == null || sources.length() == 0) {
sources = VERIFY_CODES;
}
int codesLen = sources.length();
Random rand = new Random(System.currentTimeMillis());
StringBuilder verifyCode = new StringBuilder(verifySize);
for (int i = 0; i < verifySize; i++) {
verifyCode.append(sources.charAt(rand.nextInt(codesLen - 1)));
}
return verifyCode.toString();
}
/**
* 生成随机验证码文件,并返回验证码值
*
* @param w
* @param h
* @param outputFile
* @param verifySize
* @return
* @throws IOException
*/
public static String outputVerifyImage(int w, int h, File outputFile, int verifySize) throws IOException {
String verifyCode = generateVerifyCode(verifySize);
outputImage(w, h, outputFile, verifyCode);
return verifyCode;
}
/**
* 输出随机验证码图片流,并返回验证码值
*
* @param w
* @param h
* @param os
* @param verifySize
* @return
* @throws IOException
*/
public static String outputVerifyImage(int w, int h, OutputStream os, int verifySize) throws IOException {
String verifyCode = generateVerifyCode(verifySize);
outputImage(w, h, os, verifyCode);
return verifyCode;
}
/**
* 生成指定验证码图像文件
*
* @param w
* @param h
* @param outputFile
* @param code
* @throws IOException
*/
public static void outputImage(int w, int h, File outputFile, String code) throws IOException {
if (outputFile == null) {
return;
}
File dir = outputFile.getParentFile();
if (!dir.exists()) {
dir.mkdirs();
}
try {
outputFile.createNewFile();
FileOutputStream fos = new FileOutputStream(outputFile);
outputImage(w, h, fos, code);
fos.close();
} catch (IOException e) {
throw e;
}
}
/**
* 输出指定验证码图片流
*
* @param w
* @param h
* @param os
* @param code
* @throws IOException
*/
public static void outputImage(int w, int h, OutputStream os, String code) throws IOException {
int verifySize = code.length();
BufferedImage image = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
Random rand = new Random();
Graphics2D g2 = image.createGraphics();
g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
Color[] colors = new Color[5];
Color[] colorSpaces = new Color[]{
Color.WHITE, Color.CYAN,
Color.GRAY, Color.LIGHT_GRAY, Color.MAGENTA, Color.ORANGE,
Color.PINK, Color.YELLOW};
float[] fractions = new float[colors.length];
for (int i = 0; i < colors.length; i++) {
colors[i] = colorSpaces[rand.nextInt(colorSpaces.length)];
fractions[i] = rand.nextFloat();
}
Arrays.sort(fractions);
g2.setColor(Color.GRAY);// 设置边框色
g2.fillRect(0, 0, w, h);
Color c = getRandColor(200, 250);
g2.setColor(c);// 设置背景色
g2.fillRect(0, 2, w, h - 4);
//绘制干扰线
Random random = new Random();
g2.setColor(getRandColor(160, 200));// 设置线条的颜色
for (int i = 0; i < 20; i++) {
int x = random.nextInt(w - 1);
int y = random.nextInt(h - 1);
int xl = random.nextInt(6) + 1;
int yl = random.nextInt(12) + 1;
g2.drawLine(x, y, x + xl + 40, y + yl + 20);
}
// 添加噪点
float yawpRate = 0.05f;// 噪声率
int area = (int) (yawpRate * w * h);
for (int i = 0; i < area; i++) {
int x = random.nextInt(w);
int y = random.nextInt(h);
int rgb = getRandomIntColor();
image.setRGB(x, y, rgb);
}
shear(g2, w, h, c);// 使图片扭曲
g2.setColor(getRandColor(100, 160));
int fontSize = h - 4;
Font font = new Font("Algerian", Font.ITALIC, fontSize);
g2.setFont(font);
char[] chars = code.toCharArray();
for (int i = 0; i < verifySize; i++) {
AffineTransform affine = new AffineTransform();
affine.setToRotation(Math.PI / 4 * rand.nextDouble() * (rand.nextBoolean() ? 1 : -1), (w / verifySize) * i + fontSize / 2, h / 2);
g2.setTransform(affine);
g2.drawChars(chars, i, 1, ((w - 10) / verifySize) * i + 5, h / 2 + fontSize / 2 - 10);
}
g2.dispose();
ImageIO.write(image, "png", os);
}
private static Color getRandColor(int fc, int bc) {
if (fc > 255) {
fc = 255;
}
if (bc > 255) {
bc = 255;
}
int r = fc + random.nextInt(bc - fc);
int g = fc + random.nextInt(bc - fc);
int b = fc + random.nextInt(bc - fc);
return new Color(r, g, b);
}
private static int getRandomIntColor() {
int[] rgb = getRandomRgb();
int color = 0;
for (int c : rgb) {
color = color << 8;
color = color | c;
}
return color;
}
private static int[] getRandomRgb() {
int[] rgb = new int[3];
for (int i = 0; i < 3; i++) {
rgb[i] = random.nextInt(255);
}
return rgb;
}
private static void shear(Graphics g, int w1, int h1, Color color) {
shearX(g, w1, h1, color);
shearY(g, w1, h1, color);
}
private static void shearX(Graphics g, int w1, int h1, Color color) {
int period = random.nextInt(2);
boolean borderGap = true;
int frames = 1;
int phase = random.nextInt(2);
for (int i = 0; i < h1; i++) {
double d = (double) (period >> 1)
* Math.sin((double) i / (double) period
+ (6.2831853071795862D * (double) phase)
/ (double) frames);
g.copyArea(0, i, w1, 1, (int) d, 0);
if (borderGap) {
g.setColor(color);
g.drawLine((int) d, i, 0, i);
g.drawLine((int) d + w1, i, w1, i);
}
}
}
private static void shearY(Graphics g, int w1, int h1, Color color) {
int period = random.nextInt(40) + 10; // 50;
boolean borderGap = true;
int frames = 20;
int phase = 7;
for (int i = 0; i < w1; i++) {
double d = (double) (period >> 1)
* Math.sin((double) i / (double) period
+ (6.2831853071795862D * (double) phase)
/ (double) frames);
g.copyArea(i, 0, 1, h1, 0, (int) d);
if (borderGap) {
g.setColor(color);
g.drawLine(i, (int) d, i, 0);
g.drawLine(i, (int) d + h1, i, h1);
}
}
}
public static void main(String[] args) throws IOException {
String s = GenerateCode.outputVerifyImage(400, 200, new FileOutputStream("d:/a.jpg"), 4);
// String s = GenerateCode.generateVerifyCode(5);
System.out.println(s);
}
}
实体类：
Users类：
public class Users {
private String id;
private String name;
private String psw;
public Users(String id, String name, String psw) {
this.id = id;
this.name = name;
this.psw = psw;
}
public Users(String name, String psw) {
this.name = name;
this.psw = psw;
}
@Override
public String toString() {
return "Users{" +
"id='" + id + '\'' +
", name='" + name + '\'' +
", psw='" + psw + '\'' +
'}';
}
public Users() {
}
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getPsw() {
return psw;
}
public void setPsw(String psw) {
this.psw = psw;
}
}
然后就是三层架构：
dao层：
UserDao接口：
public interface UsersDao {
List<Users> findUsers(Users users);
}
UserDaoImpl实现类：
public class UserDaoImpl implements UsersDao {
@Override
public List<Users> findUsers(Users users) {
DataSource ds = JdbcUtil.getDataSource();
JdbcTemplate template = new JdbcTemplate(ds);
List<Users> usersList = template.query("select * from users where name=? and psw=?", new BeanPropertyRowMapper<>(Users.class), users.getName(), users.getPsw());
return usersList;
}
}
service层：
UserService接口：
public interface UserService {
List<Users> findUsers(Users users);
}
UserServiceImpl实现类：
public class UserServiceImpl implements UserService {
@Override
public List<Users> findUsers(Users users) {
UserDaoImpl userDao = new UserDaoImpl();
return userDao.findUsers(users);
}
}
servlet层：
@WebServlet("/login01")
public class LoginServlet extends HttpServlet {
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
req.setCharacterEncoding("utf-8");
UserServiceImpl userService = new UserServiceImpl();
String name = req.getParameter("name");
String psw = req.getParameter("psw");
Users users1 = new Users(name, psw);
List<Users> users = userService.findUsers(users1);
String code = req.getParameter("code");
String remember = req.getParameter("remember");
//情况1：
if (users.size()==0){
req.setAttribute("msg","用户名或密码错误");
req.getRequestDispatcher("/users/login.jsp").forward(req,resp);
return;
}
//情况2：
if (!code.equalsIgnoreCase((String) req.getSession().getAttribute("code1"))){
req.setAttribute("msg","验证码错误");
req.getRequestDispatcher("/users/login.jsp").forward(req,resp);
return;
}
//特殊情况：勾选了7天免登陆
if (remember!=null&&remember.equals("yes")){
//1，覆盖了原来的cookie，生命时长为7天
Cookie c = new Cookie("JSESSIONID", req.getSession().getId());
c.setMaxAge(3600*24*7);
resp.addCookie(c);
//2，设置session的存活时间--session长时间不用，会被服务器自动回收
req.getSession().setMaxInactiveInterval(3600*24*7);
}else {
//取消7天免登陆--恢复默认
//1，覆盖原来的cookie,生命时长为默认
Cookie c = new Cookie("JSESSIONID", req.getSession().getId());
c.setMaxAge(-1); //设置为-1 表示cookie不会销毁
resp.addCookie(c);
//2，设置session的存活时间为30分钟
req.getSession().setMaxInactiveInterval(1800);
}
//情况3--登录成功
req.getSession().setAttribute("name",name);
//只有登录成功后，session中才有user--拦截依据
req.getSession().setAttribute("user",name);
req.getRequestDispatcher("/users/success.jsp").forward(req,resp);
}
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
String code = GenerateCode.outputVerifyImage(100, 40, resp.getOutputStream(), 4);
//get请求获取验证码和post请求提交表单，同属一次会话，共用同一个session对象
req.getSession().setAttribute("code1",code);
}
}
效果展示：
（注意这里的动态码是忽略大小写的，就是我们平常用的验证码）
其实这个项目并不难哟，可以尝试一下哟！