我的学习阶段是跟着CZBK黑马的双源课程，学习目标以及博客是为了审查自己的学习情况，毕竟看一遍，敲一遍，和自己归纳总结一遍有着很大的区别，在此期间我会参杂Java疯狂讲义（第四版）里面的内容。

前言：此随笔主要是Java基础中的基础，相信大家对这方面肯定有着自己的理解和认识，具体详解可以参照万能的baidu，有的我就一笔带过，希望在我的学习之路上能够有大牛进行指导，也有更多的小伙伴共勉。

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用户登录案例要求:

1.编写login.html页面有username和password两个输入框

2.使用Druid数据库连接池技术操作mysql数据库中的user表

3.使用JDBCTemplate技术封装JDBC

4.登陆成功有成功提示,登录失败有失败提示.

开发步骤:

1.创建项目导入html文件配置文件,jar包

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<form action="" method="post">
    用户名:<input type="text" name="username"> <br>
    密码:<input type="password" name="password"><br>

    <input type="submit" value="登录">

</form>
</body>
</html>

 

2.创建数据库表

CREATE DATABASE day01;
USE day01;
CREATE TABLE USER(
    id INT PRIMARY KEY AUTO_INCREMENT NOT NULL,
    username VARCHAR(32) UNIQUE NOT NULL,
    PASSWORD VARCHAR(32) NOT NULL

);

 

3.创建用户类User

package cn.zxp.domain;

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 + '\'' +
                '}';
    }
}

 

4.创建包编写工具类JDBCUtils

package cn.zxp.util;

import com.alibaba.druid.pool.DruidDataSourceFactory;

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

public class JDBCUtils {
    private static DataSource ds;

    static {
        try {
            Properties pro = new Properties();
            InputStream is = JDBCUtils.class.getClassLoader().getResourceAsStream("druid.properties");
            pro.load(is);
            ds = DruidDataSourceFactory.createDataSource(pro);
        } catch (IOException e) {
            e.printStackTrace();
        } catch (Exception e) {
            e.printStackTrace();
        }

    }
　　public static DataSource getDataSorce(){
   　　 return ds;
　　}
}

 

5.创建UserDao提供Login方法

package cn.zxp.dao;

import cn.zxp.domain.User;
import cn.zxp.util.JDBCUtils;
import org.springframework.dao.DataAccessException;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.JdbcTemplate;

public class UserDao {
    public User login(User loginUser) {
        try {
            String sql = "select * from user where username = '?' and password = '?'";
            User user = template.queryForObject(sql,
                    new BeanPropertyRowMapper<User>(User.class),
                    loginUser.getUsername(), loginUser.getPassword());

            return user;

        } catch (DataAccessException e) {
            e.printStackTrace();
            return null;
        }
    }

    private JdbcTemplate template = new JdbcTemplate(JDBCUtils.getDataSorce());
}

 

6.编写LoginServlet类

package cn.zxp.web;

import cn.zxp.dao.UserDao;
import cn.zxp.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 loginServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        req.setCharacterEncoding("utf-8");
        String username = req.getParameter("username");
        String password = req.getParameter("password");
        User loginUser = new User();
        loginUser.setUsername(username);
        loginUser.setPassword(password);

        UserDao dao = new UserDao();
        User user = dao.login(loginUser);

        if (username == null) {
            req.getRequestDispatcher("failServlet").forward(req, resp);
        } else {
            req.setAttribute("user", user);
            req.getRequestDispatcher("successServlet").forward(req, resp);
        }
    }

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

 

7.编写failServlet和successServlet

package cn.zxp.web;

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;
@WebServlet("/failServlet" )
public class failServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

        resp.setContentType("text/html;charset=utf-8");
        resp.getWriter().write("登陆错误,用户名或密码错误");
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

        this.doGet(req, resp);
    }
}
package cn.zxp.web;

import cn.zxp.domain.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;

@WebServlet("/successServlet" )
public class successServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

        User user = (User) req.getAttribute("user");
        if (user != null) {
            resp.setContentType("text/html;charset=utf-8");
            resp.setContentType("登陆成功"+user+"欢迎您");
        }
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

        this.doGet(req, resp);
    }
}

 

8.login.html中form表单的action路径写法

虚拟目录+Servlet的资源路径

9.BeanUtils工具类,简化数据封装

用来封装JavaBean的标准Javalei

 

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