用户登录案例

用户登录案例

需求：

1.编写login.html登录页面

username && oassword两个输入框

2.使用Druid数据库连接数据池技术 操作mysql videopractice数据库中user表

3.使用JdbcTemplate技术封装JDBC

4.登录成功跳转到SuccessServlet展示：登录成功 用户名,欢迎您

5.登录失败跳转到FailServlet展示：登录失败 用户名或密码错误

开发步骤:

1.创建项目 导入html页面 配置文件 依赖

html页面.

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<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>登录页面</title>
</head>
<body>
<form action="/loginServlet" method="post">
    用户名:<input type="text" name="username"><br>
    密码:<input type="text" name="password"><br>
    <input type="submit" value="登录">
</form>
</body>
</html>
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login.html中from表单的action路径的写法

  • 虚拟目录+Servlet的资源路径 

配置文件

driverClassName=com.mysql.cj.jdbc.Driver
url=jdbc:mysql:///videopractice
username=root
password=root
initialSize=5
maxActive=10
maxWait=3000

依赖

 

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<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>org.example</groupId>
    <artifactId>day_05</artifactId>
    <version>1.0-SNAPSHOT</version>
    <dependencies>
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.1.10</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-jdbc</artifactId>
            <version>5.3.18</version>
        </dependency>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.28</version>
        </dependency>

        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.5.9</version>
        </dependency>

        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.13.2</version>
            <scope>test</scope>
        </dependency>

        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>servlet-api</artifactId>
            <version>2.5</version>
        </dependency>

        <dependency>
            <groupId>commons-beanutils</groupId>
            <artifactId>commons-beanutils</artifactId>
            <version>1.7.0 </version>
        </dependency>
    </dependencies>


</project>
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2.创建数据库环境

 3.创建包com.bai.domain,创建user类

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public class User {
    private int id;
    private String username;
    private int 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 int getPassword() {
        return password;
    }

    public void setPassword(int password) {
        this.password = password;
    }

    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", username='" + username + '\'' +
                ", password=" + password +
                '}';
    }

}
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4.创建包com.bai.dao,创建类UserDao,提供login方法

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public class UserDao {
    //声明JDBCTemplate对象共用
    private JdbcTemplate template=new JdbcTemplate(JDBCUtils.getDataSource());


    /**
     * 登录方法
     * @param loginUser 只有用户名和密码
     * @return user包含用户全部数据 没有查询到 返回null
     */
    public User login(User loginUser){
        try {
            //1.编写sql
            String sql="select * from user where username= ?and password= ?";
            //2.调用query方法

            User user = template.queryForObject(sql,
                    new BeanPropertyRowMapper<User>(User.class),
                    loginUser.getUsername(), loginUser.getPassword());
            return user;
        } catch (DataAccessException e) {
            e.printStackTrace(); //打印出错信息
            return null;
        }
    }

}
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工具类

复制代码
package com.bai.util;

import com.alibaba.druid.pool.DruidDataSourceFactory;

import javax.sql.DataSource;
import java.io.IOException;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.SQLException;
import java.util.Properties;

//JDBC工具类 使用Durid连接池
public class JDBCUtils {
    private static DataSource ds;

    static {

        try {
            //1.加载配置文件
            Properties pro = new Properties();
            //使用ClassLoader加载配置文件 获取字节输入流
            InputStream is  = JDBCUtils.class.getClassLoader().getResourceAsStream("druid.properties");
            pro.load(is);

            //2.初始化连接池对象
            ds=DruidDataSourceFactory.createDataSource(pro);
        } catch (IOException e) {
            e.printStackTrace();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    /**
     * 获取连接池对象
     */
    public static DataSource getDataSource(){
        return ds;
    }
    /**
     * 获取连接Connection对象
     */
    public static Connection getConnection() throws SQLException {
        return ds.getConnection();
    }

}
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5.编写com.bai.web.Servlet.LoginServlet类

复制代码
package com.bai.web.Servlet;

import com.bai.dao.UserDao;
import com.bai.domain.User;
import com.sun.net.httpserver.HttpServer;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

public class LoginServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
       this.doPost(req,resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //1.设置编码
        req.setCharacterEncoding("utf-8");
        //2.获取请求参数
        String username = req.getParameter("username");
        String password = req.getParameter("password");
        //3.封装user对象
        User loginUser = new User();
        loginUser.setUsername(username);
        loginUser.setPassword(password);
        //4.调用UserDao的login方法
        UserDao dao = new UserDao();
        User user = dao.login(loginUser);
        //5.判断user
        if (user==null){
            //登录失败
            req.getRequestDispatcher("/failServlet").forward(req,resp);
        }else{
            //登录成功
            //转发数据
            req.setAttribute("user",user);
            //转发
            req.getRequestDispatcher("/successServlet").forward(req,resp);
        }
    }
}
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6.编写com.bai.web.Servlet.FailServlet类

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package com.bai.web.Servlet;

import javax.jws.WebService;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
public class FailServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //给页面写的一句话
        //设置编码
        resp.setContentType("text/html;charset=utf-8");
        //输出
        resp.getWriter().write("登录失败 用户名或密码错误");
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doGet(req, resp);
    }
}
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7.编写com.bai.web.Servlet.SuccessServlet类

复制代码
package com.bai.web.Servlet;

import com.bai.domain.User;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

public class SuccessServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
         //获取request域中共享的user对象
        User user = (User) req.getAttribute("user");

        if (user !=null) {
            resp.setContentType("text/html;charset=utf-8");
            //输出
            resp.getWriter().write("登录成功！"+user.getUsername()+"欢迎你");
        }
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doGet(req, resp);
    }
}
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8.BeanUtils工具类 简化数据封装

  • 用于封装JavaBean的
    • javaBean：标准的java类
      • 要求
        • 类必须被public修饰
        • 必须提供空参的构造器
        • 成员变量必须使用Private修饰
        • 提供公共setter和getter方法
      • 功能：封装数据
    • 概念：
      • 成员变量：
      • 属性：setter和getter方法后截取后的产物
        • 例如：getUsername()-->Username-->username
    • 方法
      • setProperty()
      • getProperty()
      • populate:

依赖

  <dependency>
            <groupId>commons-beanutils</groupId>
            <artifactId>commons-beanutils</artifactId>
            <version>1.7.0 </version>
        </dependency>

java代码

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package com.bai.web.Servlet;

import com.bai.dao.UserDao;
import com.bai.domain.User;
import com.sun.net.httpserver.HttpServer;
import org.apache.commons.beanutils.BeanUtils;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import java.util.Map;

public class LoginServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
       this.doPost(req,resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //1.设置编码
        req.setCharacterEncoding("utf-8");
    /*    //2.获取请求参数
        String username = req.getParameter("username");
        String password = req.getParameter("password");
        //3.封装user对象
        User loginUser = new User();
        loginUser.setUsername(username);
        loginUser.setPassword(password);*/

        //2.获取所有请求参数
        Map<String,String> map = req.getParameterMap();
        //3.创建User对象
        User loginUser = new User();
        //使用BeanUtils封装
        try {
            BeanUtils.populate(loginUser,map);
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        } catch (InvocationTargetException e) {
            e.printStackTrace();
        }

        //4.调用UserDao的login方法
        UserDao dao = new UserDao();
        User user = dao.login(loginUser);
        //5.判断user
        if (user==null){
            //登录失败
            req.getRequestDispatcher("/failServlet").forward(req,resp);
        }else{
            //登录成功
            //转发数据
            req.setAttribute("user",user);
            //转发
            req.getRequestDispatcher("/successServlet").forward(req,resp);
        }
    }
}
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运行结果

 

 

posted @   baimingze  阅读(73)  评论(0)  编辑  收藏  举报
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