利用Servlet中的Request和Response實現網頁登入效果
準備步驟
需要運行在Tomcat服務器當中
一些需要的jar包
還有個Druid.properties配置文件
Druid.properties配置文件
driverClassName=com.mysql.jdbc.Driver
url=jdbc:mysql://127.0.0.1:3306/day14
username=root
password=root前端代碼
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>登錄</title>
</head>
<body>
<form action="/demo" method="post">
用戶名:<input type="text" name="username"><br>
密碼:<input type="text" name="password"><br>
<input type="submit" value="確定">
</form>
</body>
</html>一個存儲用戶的User類
package cn.itcast.damain;
public class User {
private int id;
private String username;
private String password;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
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;
}
@Override
public String toString() {
return "User{" +
"id=" + id +
", username='" + username + '\'' +
", password='" + password + '\'' +
'}';
}
}
一個實現判斷登入的類
package cn.itcast.dao;
import cn.itcast.damain.User;
import cn.itcast.util.JDBCUtil;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.JdbcTemplate;
/**
* 操作數據庫的user表類
*/
public class UserDao {
private JdbcTemplate template = new JdbcTemplate(JDBCUtil.getDataSource());
/**
* 登入方法
* @param loginUser 傳遞一個封裝的User對象
* @return User對象
*/
public User login(User loginUser){
try {
//定義sql
String sql = "select * from user where username = ? and password = ?";
//將查詢出來的數據封裝成User對象
User user = template.queryForObject(sql,new BeanPropertyRowMapper<User>(User.class),loginUser.getUsername(),loginUser.getPassword());
return user;
}catch (Exception e){
e.printStackTrace();
//出現異常就返回null
return null;
}
}
}
jdbc工具類
package cn.itcast.util;
import com.alibaba.druid.pool.DruidDataSourceFactory;
import javax.sql.DataSource;
import java.sql.Connection;
import java.util.Properties;
public class JDBCUtil {
private static DataSource ds;
static {
try {
Properties pro = new Properties();
pro.load(JDBCUtil.class.getClassLoader().getResourceAsStream("druid.properties"));
ds = DruidDataSourceFactory.createDataSource(pro);
} catch (Exception e) {
e.printStackTrace();
}
}
/**
* 獲取連接數據庫對象
*/
public static Connection getConnection() throws Exception {
return ds.getConnection();
}
/**
* 獲取連接池對象
*/
public static DataSource getDataSource(){
return ds;
}
}
Servlet中的代碼 第一個
package cn.itcast.web.Servlet;
import cn.itcast.damain.User;
import cn.itcast.dao.UserDao;
import org.apache.commons.beanutils.BeanUtils;
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.util.Map;
//Servlet訪問路徑
@WebServlet("/demo")
public class ServletDemo extends HttpServlet {
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//設置編碼格式
req.setCharacterEncoding("utf-8");
Map<String, String[]> map = req.getParameterMap();
User loginuser = new User();
try {
//這個是javaBean的方法要導入相關的jar
/*
作用將map集合中的數據拿出來封裝成User對象
*/
BeanUtils.populate(loginuser,map);
} catch (Exception e) {
e.printStackTrace();
}
//判斷登入類
UserDao dao = new UserDao();
//判斷登入方法
User user = dao.login(loginuser);
if (user != null){
//登入成功
//共享數據中的存儲數據
req.setAttribute("user",user);
//請求轉發可以理解爲跳轉
req.getRequestDispatcher("/successServlet").forward(req,resp);
}else{
//登入失敗
//請求轉發可以理解爲跳轉
req.getRequestDispatcher("/failServlet").forward(req,resp);
}
}
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
this.doPost(req,resp);
}
}
Servlet中的代碼 第二個 登入成功代碼
package cn.itcast.web.Servlet;
import cn.itcast.damain.User;
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;
//Servlet訪問路徑
@WebServlet("/successServlet")
public class SuccessServlet extends HttpServlet {
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//設置解析格式
response.setContentType("text/html;charset=utf-8");
//這個是共享數據中的一個方法 通過鍵獲取值 返回User對象
User user = (User) request.getAttribute("user");
//這個是user.getUsername() 獲取登入成功後的用戶名將他顯示在網頁中
response.getWriter().write("歡迎"+user.getUsername()+"登入成功");
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doPost(request,response);
}
}
Servlet中的代碼 第二個 登入失敗代碼
package cn.itcast.web.Servlet;
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;
//Servlet訪問路徑
@WebServlet("/failServlet")
public class FailServlet extends HttpServlet {
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//設置解析格式
response.setContentType("text/html;charset=utf-8");
//顯示在網頁中登入失敗，用戶或密碼錯誤
response.getWriter().write("登入失敗，用戶或密碼錯誤");
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doPost(request,response);
}
}