javax.servlet
            javax.servlet-api
            3.1.0
            provided
        
        
        
        
            com.fasterxml.jackson.core
            jackson-databind
            2.12.6.1
        
        
        
        
            mysql
            mysql-connector-java
            5.1.47
        
    

4）引入前端代码

将前端的代码复制到 webapp 目录下

2. 数据库设计 

2.1 表设计

需要设计两张表，文章表和用户表

文章表用来存储博客文，用户表用于存储登录用户

--创建库
create database if not exists blog_web;

use blog_web;

drop table if exists blog;
--建博客表
create table blog (
    blogId int primary key auto_increment,
    title varchar(1024),
    content mediumtext,--内容，存放大量数据
    userId int,
    postTime datetime --时间
);

--插入数据
insert into blog values(null, '博客一', '认真学 C', 1, now());
insert into blog values(null, '博客二', '认真学 GO', 1, now());

--用户表
drop table if exists user;
create table user (
    userId int primary key auto_increment,--自增主键
    username varchar(128) unique, --用户唯一
    password varchar(128)
);
--用户
insert into user values(null, 'FlyUpward', '');--密码自己设
insert into user values(null, 'Fly', '');--密码自己设

将表复制到 mysql 中进行建表

package model;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;

public class BlogDao {
    //1.插入博客
    public void insert(Blog blog) {
        Connection connection = null;
        PreparedStatement statement = null;

        try {
            //1)和数据库建立连接
            connection = DBUtil.getConnection();
            //2)构造sql语句
            String sql = "insert into blog values(null,?,?,?,now())";
            statement = connection.prepareStatement(sql);
            statement.setString(1,blog.getTitle());
            statement.setString(2,blog.getContent());
            statement.setInt(3,blog.getUserId());
            //30执行SQL
            statement.executeUpdate();
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            DBUtil.close(connection,statement,null);
        }
    }

    // 2. 能够获取到博客表中的所有博客的信息 (用于在博客列表页, 此处每篇博客不一定会获取到完整的正文)
    public List selectAll() {
        List blogs = new ArrayList<>();
        Connection connection = null;
        PreparedStatement statement = null;
        ResultSet resultSet = null;
        try {
            connection = DBUtil. getConnection();
            String sql = "select * from blog order by postTime desc";
            statement = connection.prepareStatement(sql);
            resultSet = statement.executeQuery();//查询
            while (resultSet.next()) {
                Blog blog = new Blog();
                blog.setBlogId(resultSet.getInt("blogId"));
                blog.setTitle(resultSet.getString("title"));
                // 这里需要针对内容进行截断(太长了, 就去掉后面)
                String content = resultSet.getString("content");
                // 这个数字具体写多少, 都可以灵活应对!!
                if (content.length() > 10) {
                    content = content.substring(0,10) + "......";
                }
                blog.setContent(content);
                blog.setUserId(resultSet.getShort("userId"));
                blog.setPostTime(resultSet.getTimestamp("postTime"));
                blogs.add(blog);
            }
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            DBUtil.close(connection, statement, resultSet);
        }
        return blogs;
    }

    // 3. 能够根据博客 id 获取到指定的博客内容 (用于在博客详情页)
    public Blog selectOne(int blogId) {
        Connection connection = null;
        PreparedStatement statement = null;
        ResultSet resultSet = null;
        try {
            connection = DBUtil.getConnection();
            String sql = "select * from blog where blogId = ?";
            statement = connection.prepareStatement(sql);
            statement.setInt(1,blogId);
            resultSet = statement.executeQuery();
            // 此处我们是使用 主键 来作为查询条件的. 查询结果, 要么是 1 , 要么是 0.
            if (resultSet.next()) {
                Blog blog = new Blog();
                blog.setBlogId(resultSet.getInt("blogId"));
                blog.setTitle(resultSet.getString("title"));
                blog.setContent(resultSet.getString("content"));
                blog.setUserId(resultSet.getShort("userId"));
                blog.setPostTime(resultSet.getTimestamp("postTime"));
                return blog;
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }finally {
            DBUtil.close(connection, statement, resultSet);
        }
        return null;
    }


    // 4. 从博客表中, 根据博客 id 删除博客.
    public void delete(int blogId) {
        Connection connection = null;
        PreparedStatement statement = null;
        try {
            connection = DBUtil.getConnection();
            String sql = "delete from blog where blogId = ?";
            statement = connection.prepareStatement(sql);
            statement.setInt(1,blogId);
            statement.executeUpdate();
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            DBUtil.close(connection, statement, null);
        }
    }
}

2）创建 UserDao 类

package model;


import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

//提供了针对用户表的基本操作
public class UserDao {

    public void insert(User user){
        Connection connection = null;
        PreparedStatement statement = null;
        try {
            connection = DBUtil.getConnection();
            String sql = "insert into user values(null,?,?)";
            statement = connection.prepareStatement(sql);
            statement.setString(1, user.getUsername());
            statement.setString(2, user.getPassword());
            statement.executeUpdate();
        } catch (SQLException throwables) {
            throwables.printStackTrace();
        }finally {
            DBUtil.close(connection,statement,null);
        }
    }

    //主要实现
    // 1. 根据用户名来查找用户信息
    //这个会在登录逻辑中使用
    public User selectByName(String username) {
        Connection connection = null;
        PreparedStatement statement = null;
        ResultSet resultSet = null;
        try {
            connection = DBUtil.getConnection();
            String sql = "select * from user where username = ?";
            statement = connection.prepareStatement(sql);
            statement.setString(1, username);
            resultSet = statement.executeQuery();
            // 此处 username 使用 unique 约束, 要么能查到一个, 要么一个都查不到.
            if (resultSet.next()) {
                User user = new User();
                user.setUserId(resultSet.getInt("userId"));
                user.setUsername(resultSet.getString("username"));
                user.setPassword(resultSet.getString("password"));
                return user;
            }
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            DBUtil.close(connection, statement, resultSet);
        }
        return null;
    }

    // 2. 根据用户 id 来找用户信息.
    //    博客详情页, 就可以根据用户 id 来查询作者的名字, 把作者名字显示出来.
    public User selectById(int userId) {
        Connection connection = null;
        PreparedStatement statement = null;
        ResultSet resultSet = null;
        try {
            connection = DBUtil.getConnection();
            String sql = "select * from user where userId = ?";
            statement = connection.prepareStatement(sql);
            statement.setInt(1, userId);
            resultSet = statement.executeQuery();
            // 此处 username 使用 unique 约束, 要么能查到一个, 要么一个都查不到.
            if (resultSet.next()) {
                User user = new User();
                user.setUserId(resultSet.getInt("userId"));
                user.setUsername(resultSet.getString("username"));
                user.setPassword(resultSet.getString("password"));
                return user;
            }
        } catch (SQLException throwables) {
            throwables.printStackTrace();
        } finally {
            DBUtil.close(connection, statement, resultSet);
        }
        return null;
    }
}