简单的登录页面：
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>login</title>
</head>
<body>
<!-- web3:项目名,在LoginServlet前必须加项目名，如果不加则默认视为工作空间地址 -->
<form action="/web3/LoginServlet" method="post">
username:<input type="text" name="username" />
password:<input type="password" name="password" />
<input type="submit" value="login">
</form>
</body>
</html>
登录成功页面：
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>login</title>
</head>
<body>
登录成功！！
</body>
</html>
登录失败页面：
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>login</title>
</head>
<body>
登录成功！！
</body>
</html>
Servlet处理代码：
public class LoginServlet extends HttpServlet {
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doPost(request, response);
}
// 使用doPost()可以隐藏向服务器发送请求的内容
@Override
protected void doPost(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
ServletContext application = getServletContext();
// 设置服务器返回页面的编码，如果不设置默认会使中文乱码
response.setContentType("text/html;Charset=utf-8");
// 获取<input type="?" name="username">中的username的值
String username = request.getParameter("username");
String password = request.getParameter("password");
// 如果请求中username为空，把username改为空字符串，避免指针为空的异常
if (username == null) {
username = "";
}
if (password == null) {
password = "";
}
PrintWriter out = response.getWriter();
out.println(username + ":" + password);
User user = new User(username, password);
// mvc结构
UserDao userDao = new UserDao();
// 判断是否有值返回
boolean b = userDao.getUserByNameAndPassword(user);
if (b) {
// 跳转到success.html页面
RequestDispatcher requestDispatcher = application
.getRequestDispatcher("/success.html");
requestDispatcher.forward(request, response);
} else {
RequestDispatcher requestDispatcher = application
.getRequestDispatcher("/fail.html");
//将fail.html包含在当前页面内部
requestDispatcher.include(request, response);
}
}
}
Servlet配置：
<!-- login -->
<servlet>
<servlet-name>LoginServlet</servlet-name>
<servlet-class>com.gem.servlet.LoginServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>LoginServlet</servlet-name>
<url-pattern>/LoginServlet</url-pattern>
</servlet-mapping>
连接数据库：
public class DBUtils {
public static Connection getConnection() {
try {
Class.forName("com.mysql.jdbc.Driver");
String url = "jdbc:mysql://localhost:3306/school";
String user = "root";
String password = "rootpassword";
return DriverManager.getConnection(url, user, password);
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return null;
}
}
建表语句：
CREATE TABLE user_test( id int PRIMARY KEY auto_increment, username VARCHAR(12) not null, userpassword VARCHAR(12) not null ) INSERT INTO user_test(username,userpassword) VALUES(‘tom‘,‘123456‘); SELECT username,userpassword from user_test WHERE username=‘tom‘ and userpassword=‘123456‘
UserDao与数据库交互：
public class UserDao {
public boolean getUserByNameAndPassword(User user) {
Connection connection = DBUtils.getConnection();
PreparedStatement preparedStatement=null;
ResultSet resultSet=null;
String sql = "SELECT * from user_test WHERE username=? and userpassword=?";
try {
preparedStatement = connection.prepareStatement(sql);
preparedStatement.setString(1, user.getName());
preparedStatement.setString(2, user.getPassword());
resultSet=preparedStatement.executeQuery();
if (resultSet.next()) {
return true;
}
} catch (SQLException e) {
e.printStackTrace();
}finally{
if (resultSet!=null) {
try {
resultSet.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
if (preparedStatement!=null) {
try {
preparedStatement.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
if (connection!=null) {
try {
connection.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
return false;
}
}
User实体类：
package com.gem.pojo;
public class User {
private String name;
private String password;
public User() {
}
public User(String name, String password) {
super();
this.name = name;
this.password = password;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
}
时间： 2024-08-08 22:10:13