十一、通过匹配数据库中存储的用户名、密码信息进行登录
1、通过前台对输入的用户名、密码、id进行与存储在数据库t_user表中的信息进行匹配，如果匹配则跳转到登录成功页面。不匹配则跳转到登录失败页面
LoginServlet
import java.io.IOException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import sun.awt.RepaintArea;
public class LoginServlet extends HttpServlet {
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
req.setCharacterEncoding("UTF-8");
String name = req.getParameter("name");
String password = req.getParameter("password");
String id=req.getParameter("id");
System.out.println(name);
System.out.println(password);
System.out.println(Integer.parseInt(id));
Connection conn = null;
PreparedStatement ps = null;
ResultSet rs = null;
boolean loginSuccess = false;
// 连接数据库验证用户名和密码
try {
// 1、注册驱动
Class.forName("oracle.jdbc.OracleDriver");
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
try {
// 2、获取连接
conn = DriverManager.getConnection(
"jdbc:oracle:thin:@10.125.4.55:1521:orcl", "zsgsdfgs",
"zds123");
conn.setAutoCommit(false);
String sqlString = "select * from t_user where username=? and password=? and id=?";
ps=conn.prepareStatement(sqlString);
System.out.println(ps);
ps.setString(1, name);
ps.setString(2, password);
ps.setInt(3, Integer.parseInt(id));
rs = ps.executeQuery();
if (rs.next()) {
loginSuccess = true;
}
conn.commit();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} finally {
if (rs != null) {
try {
rs.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
if (conn != null) {
try {
conn.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
if (ps != null) {
try {
ps.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
if (loginSuccess) {
resp.sendRedirect(req.getContextPath() + "/welcome.html");
} else {
resp.sendRedirect(req.getContextPath() + "/login_error.html");
}
}
}
web.xml
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0">
<display-name>prj-servlet12</display-name>
<welcome-file-list>
<welcome-file>index.html</welcome-file>
<welcome-file>index.htm</welcome-file>
<welcome-file>index.jsp</welcome-file>
<welcome-file>default.html</welcome-file>
<welcome-file>default.htm</welcome-file>
<welcome-file>default.jsp</welcome-file>
<welcome-file>Login.html</welcome-file>
</welcome-file-list>
<servlet>
<servlet-name>login</servlet-name>
<servlet-class>LoginServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>login</servlet-name>
<url-pattern>/login</url-pattern>
</servlet-mapping>
</web-app>
login.html
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>登录页面</title>
</head>
<body>
<form action="/prj-servlet12/login" method="post">
username<input type="text" name="name">
password<input type="text" name="password">
id<input type="text" name="id">
<input type="submit" value="login">
</form>
</body>
</html>
welcome.html
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>welcome page</title>
</head>
<body>
login success,welcome!
</body>
</html>
login_error.html
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
登录失败，用户名不存在，或者密码错误，请重新<a href="/prj-servlet19/login.html">登录</a>
</body>
</html>
