JavaWeb 项目 --- 博客系统

转x33g5p2x  于2022-05-16 转载在 Java  
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1. 创建 maven 项目

创建必要的目录.引入需要的依赖

2. 设计数据库

本系统要存入博客文章的信息,
创建博客表.博客的id,博客的标题,博客的内容,博客的日期,博文的博主id
也要存入用户的信息,
创建用户表,用户id,用户名,用户密码

create database if not exists MyBlogSystem;

use MyBlogSystem;

drop table if exists blog;

-- 创建一个博客表
create table blog (
    blogId int primary key auto_increment,
    title varchar(1024),
    content mediumtext,
    postTime datetime,
    userId int
);

drop table if exists user;

-- 创建一个用户信息表
create table user (
    userId int primary key auto_increment,
    username varchar(128) unique,
    password varchar(128)
);

3. 封装数据库的操作代码

创建包Dao用来放数据库的代码.

3.1 创建 DBUtil 类

用来连接数据库

package Dao;

import com.mysql.jdbc.jdbc2.optional.MysqlDataSource;

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

public class DBUtil {
    private static final String URL = "jdbc:mysql://127.0.0.1:3306/MyBlogSystem?characterEncoding=utf8&useSSL=true&serverTimezone=UTC";
    private static final String USERNAME = "root";
    private static final String PASSWORD = "0000";

    private static volatile DataSource dataSource = null;

    private static DataSource getDataSource() {
        if(dataSource == null){
            synchronized(DBUtil.class){
                if(dataSource == null){
                    dataSource = new MysqlDataSource();
                    ((MysqlDataSource) dataSource).setURL(URL);
                    ((MysqlDataSource) dataSource).setUser(USERNAME);
                    ((MysqlDataSource) dataSource).setPassword(PASSWORD);
                }
            }
        }
        return dataSource;
    }

    public static Connection getConnection() throws SQLException {
        return getDataSource().getConnection();
    }

    public static void close(Connection connection, PreparedStatement statement, ResultSet resultSet){
        if(resultSet != null){
            try {
                resultSet.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
        if(statement != null){
            try {
                statement.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
        if(connection != null){
            try {
                connection.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }
}

3.2 创建类 Blog (代表一篇博客)

Blog

package Dao;

import java.sql.Timestamp;

public class Blog {
    public int blogId;
    public String title;
    public String content;
    public Timestamp postTime;
    public int userId;

    public int getBlogId() {
        return blogId;
    }

    public void setBlogId(int blogId) {
        this.blogId = blogId;
    }

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    public String getContent() {
        return content;
    }

    public void setContent(String content) {
        this.content = content;
    }

    public Timestamp getPostTime() {
        return postTime;
    }

    public void setPostTime(Timestamp postTime) {
        this.postTime = postTime;
    }

    public int getUserId() {
        return userId;
    }

    public void setUserId(int userId) {
        this.userId = userId;
    }
}

3.3 创建类 User (代表一个用户)

package Dao;

public class User {
    public int userId;
    public String username;
    public String password;

    public int getUserId() {
        return userId;
    }

    public void setUserId(int userId) {
        this.userId = userId;
    }

    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;
    }
}

3.4 创建类 BlogDao (对博客表进行操作)

package Dao;

import java.sql.*;
import java.util.ArrayList;
import java.util.List;

public class BlogDao {
    // 1. 插入一篇博客
    public void insert(Blog blog) {
        Connection connection = null;
        PreparedStatement statement = null;
        try {
            // 1. 建立连接
            connection = DBUtil.getConnection();
            // 2. 拼装 SQL 语句
            String sql = "insert into blog values(null,?,?,?,?)";
            statement = connection.prepareStatement(sql);
            statement.setString(1,blog.getTitle());
            statement.setString(2,blog.getContent());
            statement.setTimestamp(3,blog.getPostTime());
            statement.setInt(4,blog.getUserId());
            // 3. 执行 SQL 语句
            int ret = statement.executeUpdate();
            if(ret == 1){
                System.out.println("插入成功");
            }else {
                System.out.println("插入失败");
            }
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            DBUtil.close(connection,statement,null);
        }
    }

    // 2. 获取全部博客
    public List<Blog> selectAll() {
        Connection connection = null;
        PreparedStatement statement = null;
        ResultSet resultSet = null;
        List<Blog> list = new ArrayList<>();
        try {
            // 1. 建立连接
            connection = DBUtil.getConnection();
            // 2. 拼装 SQL 语句
            // 这里加上order by postTime desc 就可以根据时间排序了.
            String sql = "select * from blog order by postTime desc ";
            statement = connection.prepareStatement(sql);
            // 3. 执行 SQL 语句
            resultSet = statement.executeQuery();
            // 4. 遍历结果集
            while (resultSet.next()){
                Blog blog = new Blog();
                blog.setBlogId(resultSet.getInt("blogId"));
                blog.setTitle(resultSet.getString("title"));
                blog.setContent(resultSet.getString("content"));
                blog.setPostTime(resultSet.getTimestamp("postTime"));
                blog.setUserId(resultSet.getInt("userId"));
                list.add(blog);
            }
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            DBUtil.close(connection,statement,resultSet);
        }
        return list;
    }

    // 3. 获取个人博客
    public List<Blog> selectAllPerson(int userId){
        Connection connection = null;
        PreparedStatement statement = null;
        ResultSet resultSet = null;
        List<Blog> list = new ArrayList<>();
        try {
            // 1. 建立连接
            connection = DBUtil.getConnection();
            // 2. 拼装 SQL 语句
            // 这里加上order by postTime desc 就可以根据时间排序了.
            String sql = "select * from blog where userId = ? order by postTime desc ";
            statement = connection.prepareStatement(sql);
            statement.setInt(1,userId);
            // 3. 执行 SQL 语句
            resultSet = statement.executeQuery();
            // 4. 遍历结果集
            while (resultSet.next()){
                Blog blog = new Blog();
                blog.setBlogId(resultSet.getInt("blogId"));
                blog.setTitle(resultSet.getString("title"));
                blog.setContent(resultSet.getString("content"));
                blog.setPostTime(resultSet.getTimestamp("postTime"));
                blog.setUserId(resultSet.getInt("userId"));
                list.add(blog);
            }
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            DBUtil.close(connection,statement,resultSet);
        }
        return list;
    }

    // 4. 根据文章id获取指定博客
    public Blog selectOne(int blogId) {
        Connection connection = null;
        PreparedStatement statement = null;
        ResultSet resultSet = null;
        try {
            // 1. 建立连接
            connection = DBUtil.getConnection();
            // 2. 拼装 SQL 语句
            // 这里加上order by postTime desc 就可以根据时间排序了.
            String sql = "select * from blog where blogId = ? ";
            statement = connection.prepareStatement(sql);
            statement.setInt(1,blogId);
            // 3. 执行 SQL 语句
            resultSet = statement.executeQuery();
            // 4. 遍历结果集
            if (resultSet.next()){
                Blog blog = new Blog();
                blog.setBlogId(resultSet.getInt("blogId"));
                blog.setTitle(resultSet.getString("title"));
                blog.setContent(resultSet.getString("content"));
                blog.setPostTime(resultSet.getTimestamp("postTime"));
                blog.setUserId(resultSet.getInt("userId"));
                return blog;
            }
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            DBUtil.close(connection,statement,resultSet);
        }
        return null;
    }

    // 5. 删除指定文章id的博客
    public void delete(int blogId) {
        Connection connection = null;
        PreparedStatement statement = null;
        try {
            // 1. 建立连接
            connection = DBUtil.getConnection();
            // 2. 拼装 SQL 语句
            String sql = "delete from blog where blogId = ?";
            statement = connection.prepareStatement(sql);
            statement.setInt(1,blogId);
            // 3. 执行 SQL 语句
            int ret = statement.executeUpdate();
            if(ret == 1){
                System.out.println("删除成功");
            }else{
                System.out.println("删除失败");
            }
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            DBUtil.close(connection,statement,null);
        }
    }
    // 6. 计算个人文章的总数
    public Integer selectTotal(int userId) {
        Connection connection = null;
        PreparedStatement statement = null;
        ResultSet resultSet = null;
        try {
            // 1. 建立连接
            connection = DBUtil.getConnection();
            // 2. 拼装 SQL 语句
            String sql = "select count(userId) from blog where userId = ?";
            statement = connection.prepareStatement(sql);
            statement.setInt(1,userId);
            // 3. 执行 SQL 语句
            resultSet = statement.executeQuery();
            // 4. 遍历结果集
            if (resultSet.next()){
                return resultSet.getInt("count(userId)");
            }
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            DBUtil.close(connection,statement,resultSet);
        }
        return null;
    }

    public static void main(String[] args) {
        BlogDao blogDao = new BlogDao();
        Blog blog = new Blog();
        blog.setContent("你好");
        blog.setTitle("你好");
        blog.setUserId(1);
        blog.setPostTime(new Timestamp(System.currentTimeMillis()));
        blogDao.insert(blog);

        System.out.println(blogDao.selectAll());
    }
}

3.5 创建类 UserDao (对用户表进行操作)

package Dao;

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

public class UserDao {
    // 注册账号
    public void insert(User user){
        Connection connection = null;
        PreparedStatement statement = null;
        try {
            // 1. 建立连接
            connection = DBUtil.getConnection();
            // 2. 拼装 SQL 语句
            String sql = "insert into user values (null,?,?)";
            statement = connection.prepareStatement(sql);
            statement.setString(1,user.getUserName());
            statement.setString(2, user.getPassWord());
            // 3. 执行 SQL 语句
            int ret = statement.executeUpdate();
            if(ret == 1){
                System.out.println("注册成功!");
            }else{
                System.out.println("注册失败!");
            }
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            DBUtil.close(connection,statement,null);
        }
    }
    // 通过用户名查找
    public User selectByName(String username){
        Connection connection = null;
        PreparedStatement statement = null;
        ResultSet resultSet = null;
        try {
            // 1. 建立连接
            connection = DBUtil.getConnection();
            // 2. 拼装 SQL 语句
            String sql = "select * from user where username = ?";
            statement = connection.prepareStatement(sql);
            statement.setString(1,username);
            // 3. 执行 SQL 语句
            resultSet = statement.executeQuery();
            // 4. 查找结果集
            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;
    }
    // 通过用户id查找
    public User selectById(int userId){
        Connection connection = null;
        PreparedStatement statement = null;
        ResultSet resultSet = null;
        try {
            // 1. 建立连接
            connection = DBUtil.getConnection();
            // 2. 拼装 SQL 语句
            String sql = "select * from user where userId = ?";
            statement = connection.prepareStatement(sql);
            statement.setInt(1,userId);
            // 3. 执行 SQL 语句
            resultSet = statement.executeQuery();
            // 4. 遍历结果集
            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;
    }
}

4. 初始化 TemplateEngine

package View;

import org.thymeleaf.TemplateEngine;
import org.thymeleaf.templateresolver.ServletContextTemplateResolver;

import javax.servlet.ServletContext;
import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
import javax.servlet.annotation.WebListener;

@WebListener
public class ThymeleafConfig implements ServletContextListener {
    @Override
    public void contextInitialized(ServletContextEvent servletContextEvent) {
        ServletContext context = servletContextEvent.getServletContext();
        // 1. 创建 engine 实例
        TemplateEngine engine = new TemplateEngine();
        // 2. 创建 resolve 对象
        ServletContextTemplateResolver resolver = new ServletContextTemplateResolver(context);
        resolver.setCharacterEncoding("utf-8");
        resolver.setPrefix("/WEB-INF/template/");
        resolver.setSuffix(".html");
        // 3. 把 resolve 对象和 engine 关联起来
        engine.setTemplateResolver(resolver);
        // 4. 把 engine 放到 ServletContext;
        context.setAttribute("engine",engine);
    }

    @Override
    public void contextDestroyed(ServletContextEvent servletContextEvent) {

    }
}

5. 实现主页界面

观看可以看出,内容的部分是动态的,其他都是静态的.(用户个人界面暂不管)

5.1 创建网页模板

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <link rel="stylesheet" href="css/list.css">
    <link rel="stylesheet" href="css/common.css">
</head>
<body>
<div class="nav">
    <img src="image/2.png" alt="头像">
    <span class="title">我的博客系统</span>
    <a href="home.html">主页</a>
    <a href="edit.html">创作</a>
    <a href="login.html">注销</a>
</div>

<div class="parent">
    <div class="left">
        <div class="card">
            <img src="image/头像.jpg">
            <span class="name">蜡笔小新</span>
            <a href="#">github 地址</a>
            <div class='one'>
                <span>文章</span>
                <span>分类</span>
            </div>
            <div class='one'>
                <span>2</span>
                <span>1</span>
            </div>
        </div>
    </div>
    <div class="right">
        <div class="article" th:each="blog : ${blogs}">
            <h2 class="title" th:text="${blog.title}">我的第一篇博客</h2>
            <span class="date" th:text="${blog.postTime}">2022-4-17</span>
            <div class="desc" th:text="${blog.content}">今天开始我要认真写博客</div>
            <a th:href="${'details.html?blogId=' + blog.blogId}" class="more" >查看全文&gt;&gt;</a>
        </div>
    </div>
</div>

</body>
</html>

5.2 创建 IndexServlet

package View;

import Dao.Blog;
import Dao.BlogDao;
import org.thymeleaf.TemplateEngine;
import org.thymeleaf.context.WebContext;

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.List;

@WebServlet("/index.html")
public class IndexServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        resp.setContentType("text/html;charset=utf-8");

        // 1.从数据库拿到所有的博客列表
        BlogDao blogDao = new BlogDao();
        List<Blog> blogs = blogDao.selectAll();
        // 2.通过模板引擎渲染页面
        TemplateEngine engine = (TemplateEngine) getServletContext().getAttribute("engine");
        WebContext webContext = new WebContext(req,resp,getServletContext());
        webContext.setVariable("blogs",blogs);
        engine.process("index",webContext, resp.getWriter());
    }
}

5.3 发现问题

插入太多会超出文章的页面

在之前css里面加上 overflow: auto 就有一个滚动条了

发现显示的内容每次显示的情况不一样

只需更改 SelectAll()中的代码.这里的80是随便设置的

6. 实现详情页界面

6.1 创建网页模板

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <link rel="stylesheet" href="css/moreList.css">
  <link rel="stylesheet" href="css/common.css">
</head>
<body>
<div class="nav">
  <img src="image/2.png" alt="头像">
  <span class="title">我的博客系统</span>
  <a href="home.html">主页</a>
  <a href="edit.html">创作</a>
  <a href="login.html">注销</a>
</div>
<div class="parent">
  <div class="left">
    <div class="card">
      <img src="image/头像.jpg">
      <span class="name">蜡笔小新</span>
      <a href="#">github 地址</a>
      <div class='one'>
        <span>文章</span>
        <span>分类</span>
      </div>
      <div class='one'>
        <span>2</span>
        <span>1</span>
      </div>
    </div>
  </div>
  <div class="right">
    <div class="article">
      <h2 class="title" th:text="${blog.title}">我的第一篇博客</h2>
      <span class="date" th:text="${blog.postTime}">2022-4-17</span>
      <div class="desc" th:text="${blog.content}">1</div>
    </div>
  </div>
</div>
</body>
</html>

6.2 创建 DetailsServlet

package View;

import Dao.Blog;
import Dao.BlogDao;
import com.sun.xml.internal.bind.v2.schemagen.xmlschema.List;
import org.thymeleaf.TemplateEngine;
import org.thymeleaf.context.WebContext;

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("/details.html")
public class DetailsServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        resp.setContentType("text/html;charset=utf-8");

        String str = req.getParameter("blogId");
        if(str == null || str.length() == 0){
            resp.getWriter().write("blogId缺失!");
            return;
        }
        int blogId = Integer.parseInt(str);
        BlogDao blogDao = new BlogDao();
        Blog blog = blogDao.selectOne(blogId);
        if(blog == null){
            resp.getWriter().write("当前博客不存在!");
            return;
        }

        TemplateEngine engine = (TemplateEngine) getServletContext().getAttribute("engine");
        WebContext webContext = new WebContext(req,resp,getServletContext());
        webContext.setVariable("blog",blog);

        engine.process("details",webContext,resp.getWriter());
    }
}

7. 实现博客登录界面

7.1 修改之前的前端代码

7.2 创建 LoginServlet

package View;

import Dao.User;
import Dao.UserDao;

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 javax.servlet.http.HttpSession;
import java.io.IOException;

@WebServlet("/login")
public class LoginServlet extends HttpServlet {
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        resp.setContentType("text/html;charset=utf-8");
        // 1. 获取用户名密码
        String username = req.getParameter("username");
        String password = req.getParameter("password");
        // 2. 判断用户名密码是否为空
        if(username == null || "".equals(username) || password == null || "".equals(password)){
            resp.getWriter().write("<h3>用户名或者密码为空,登录失败!</h3>");
            return;
        }
        // 3. 判断输入的用户名或者密码是否正确
        UserDao userDao = new UserDao();
        User user = userDao.selectByName(username);
        if(user == null){
            resp.getWriter().write("<h3>用户名或者密码错误,登录失败!</h3>");
            return;
        }

        if(!user.getPassWord().equals(password)){
            resp.getWriter().write("<h3>用户名或者密码错误,登录失败!</h3>");
            return;
        }
        // 4. 登陆成功,就把user存到HttpSession中
        HttpSession session = req.getSession(true);
        session.setAttribute("user",user);
        // 5. 重定向到主页
        resp.sendRedirect("index.html");
    }
}

8. 实现博客的注销功能

8.1 创建 LogoutServlet 类

package View;

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 javax.servlet.http.HttpSession;
import java.io.IOException;

@WebServlet("/logout")
public class LogoutServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        resp.setContentType("text/html;charset=utf-8");
        // 1. 检查当前的用户是否登录
        HttpSession session = req.getSession(false);
        if(session == null){
            resp.getWriter().write("<h3>当前未登录</h3>");
            return;
        }
        // 2. 删除user
        session.removeAttribute("user");
        // 3. 重定向到登录页面
        resp.sendRedirect("login.html");
    }
}

9. 实现博客的注册功能

9.1 创建前端页面

<!doctype html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport"
          content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <link rel="stylesheet" href="css/common.css">
    <link rel="stylesheet" href="css/login.css">
</head>
<body>
<div class="nav">
    <img src="image/logo.png" alt="头像">
    <span class="title">我的博客系统</span>
    <a href="index.html">主页</a>
    <a href="edit.html">创作</a>
    <a href="register.html">注册</a>
</div>
<div id="one">
    <div class="login">
        <form action="register" method="post">
            <div class="text">注册</div>
            <div class="one"><span class="name">用户名</span><input type="text" class="user" name="username"></div>
            <div class="one"><span class="name">密码</span><input type="password" class="password" name="password1"></div>
            <div class="one"><span class="name">确认密码</span><input type="password" class="password" name="password2"></div>
            <div class="submit"><input type="submit" value="注 册" ></div>
        </form>
    </div>
</div>
</body>
</html>

9.2 创建 RegisterServlet

package View;

import Dao.User;
import Dao.UserDao;

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("/register")
public class RegisterServlet extends HttpServlet {
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        resp.setContentType("text/html; charset=utf-8");

        // 1. 获取输入的用户名和密码
        String username = req.getParameter("username");
        String password1 = req.getParameter("password1");
        String password2 = req.getParameter("password2");
        // 2. 如果有一个为空就注册失败
        if (username == null || password1 == null || password2 == null || "".equals(username) || "".equals(password1) || "".equals(password2)) {
            resp.getWriter().write("<h3>输入有误!注册失败!</h3>");
            return;
        }
        UserDao userDao = new UserDao();
        User user = userDao.selectByName(username);
        // 如果user不为空.表示有人注册了
        if(user!=null){
            resp.getWriter().write("<h3>用户名已经被使用了</h3>");
            return;
        }
        // 如果两次密码不一致注册失败
        if(!password1.equals(password2)){
            resp.getWriter().write("<h3>两次输入的密码不一致,注册失败!");
            return;
        }
        // 这里就注册成功了
        User user1 = new User();
        user1.setUserName(username);
        user1.setPassWord(password1);
        userDao.insert(user1);

        resp.sendRedirect("login.html");
    }
}

10. 实现博客编辑界面

10.1 修改之前前端代码

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <link rel="stylesheet" href="css/common.css">
    <link rel="stylesheet" href="css/edit.css">
    <!-- 引入 editor.md 的依赖 -->
    <link rel="stylesheet" href="editor.md/css/editormd.min.css" />
    <script src="js/jquery.min.js"></script>
    <script src="editor.md/lib/marked.min.js"></script>
    <script src="editor.md/lib/prettify.min.js"></script>
    <script src="editor.md/editormd.js"></script>
</head>
<body>
<div class="nav">
    <img src="image/2.png" alt="头像">
    <span class="title">我的博客系统</span>
    <a href="index.html">主页</a>
    <a href="edit.html">创作</a>
    <a href="logout">注销</a>
</div>
<div class="leader">
    <form action="edit" method="post" style="height:100%">
        <div class="empOne">
            <input type="text" class="title" value="在这里写下文章标题" onblur="if(this.value == '')this.value='在这里写下文章标题';" onclick="if(this.value == '在这里写下文章标题')this.value='';" name="title">
            <input type="submit" value="发布文章" class="publish">
        </div>
        <div id="editor">
            <textarea name="content" style="display:none;"></textarea>
        </div>
    </form>
</div>

<script>
        // 初始化编辑器
        var editor = editormd("editor", {
            // 这里的尺寸必须在这里设置. 设置样式会被 editormd 自动覆盖掉.
            width: "100%",
            // 高度 100% 意思是和父元素一样高. 要在父元素的基础上去掉标题编辑区的高度
            height: "calc(100% - 75px)",
            // 编辑器中的初始内容
            markdown: "# 在这里写下一篇博客",
            // 指定 editor.md 依赖的插件路径
            path: "editor.md/lib/",
            saveHTMLToTextarea: true
        });
    </script>
</body>
</html>

10.2 实现 EditServlet

package View;

import Dao.Blog;
import Dao.BlogDao;

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.sql.Timestamp;

@WebServlet("/edit")
public class EditServlet extends HttpServlet {
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        resp.setContentType("text/html;charset=utf-8");

        // 1. 获取参数
        String title = req.getParameter("title");
        String content = req.getParameter("content");
        // 2. 判断是否存在
        if(title==null || "".equals(title) || content==null || "".equals(content)){
            resp.getWriter().write("<h3>文章标题或者内容不存在</h3>");
            return;
        }

        // 插入到数据库中
        Blog blog = new Blog();
        blog.setContent(content);
        blog.setTitle(title);
        blog.setPostTime(new Timestamp(System.currentTimeMillis()));
        BlogDao blogDao = new BlogDao();
        blogDao.insert(blog);
        // 重定向
        resp.sendRedirect("index.html");
    }
}

11. 实现博客的删除功能

11.1 查看博客详情页

根据这里的blogId查找当前的userId,如果登录的userId等于当前的userId 就有删除按钮

前端改进

添加样式

#deleteA {
    margin: 5px;
    display: block;
    text-align: center;
    color:black;
    text-decoration: none;
}

#deleteA:hover{
    background-color: rgba(206, 144, 64, 0.8);
}

修改 DetailsServlet

11.2 创建 DeleteServlet

package View;
import Dao.BlogDao;

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("/delete")
public class DeleteServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        resp.setContentType("text/html;charset=utf-8");
        String str = req.getParameter("blogId");
        int blogId = Integer.parseInt(str);
        BlogDao blogDao = new BlogDao();
        blogDao.delete(blogId);
        resp.sendRedirect("index.html");
    }
}

12. 改进

12.1 点击每个页面的时候,判断是否登录了

12.1.1 创建一个 Util类

package common;

import Dao.User;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;

public class Util {
    public static User checkLoginStatus (HttpServletRequest req){
        // 判断是否登录了. 如果能够拿到 Session, 并且拿到 Session 里的 user对象,就认为是登录状态
        HttpSession session = req.getSession(false);
        if(session == null){
            // 没有登录的情况
            return null;
        }
        User user = (User) session.getAttribute("user");

        return user;
    }

}

12.1.2 改进各个界面的代码

12.2 对个人资料的名字进行修改.

12.3 内容没有支持markdown语法

12.3.1 修改details.html的代码

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <link rel="stylesheet" href="css/moreList.css">
  <link rel="stylesheet" href="css/common.css">

  <!-- 引入 editor.md 的依赖 -->
  <link rel="stylesheet" href="editor.md/css/editormd.min.css" />
  <script src="js/jquery.min.js"></script>
  <script src="editor.md/lib/marked.min.js"></script>
  <script src="editor.md/lib/prettify.min.js"></script>
  <script src="editor.md/editormd.js"></script>
</head>
<body>
<div class="nav">
  <img src="image/2.png" alt="头像">
  <span class="title">我的博客系统</span>
  <a href="index.html">主页</a>
  <a href="personlist.html">我的</a>
  <a href="edit.html">创作</a>
  <a href="logout">注销</a>
</div>
<div class="parent">
  <div class="left">
    <div class="card">
      <img src="image/头像.jpg">
      <span class="name" th:text="${user.username}">蜡笔小新</span>
      <a href="#">github 地址</a>
      <div class='one'>
        <span>文章</span>
        <span>分类</span>
      </div>
      <div class='one'>
        <span>2</span>
        <span>1</span>
      </div>
    </div>
  </div>
  <div class="right">
    <div class="article">
      <h2 class="title" th:text="${blog.title}">我的第一篇博客</h2>
      <span class="date" th:text="${blog.postTime}">2022-4-17</span>
      <a th:href="${'delete?blogId=' + blog.blogId}" id="deleteA" th:if="${showDelete}">删除文章</a>
      <div class="desc" id="content" th:text="${blog.content}" style="background-color: transparent;"></div>
    </div>
  </div>
</div>

<script>
  function renderMD() {
      let contentDiv = document.querySelector('#content');
      let markdown = contentDiv.innerHTML;
      // 1把contentDiv清空
      contentDiv.innerHTML = '';
      editormd.markdownToHTML('content',{
          markdown: markdown
      });
  }
  renderMD();
</script>
</body>
</html>

12.4 在左侧动态的显示自己的文章总数

13. 添加个人主页功能

13.1 创建前端代码

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <link rel="stylesheet" href="css/list.css">
    <link rel="stylesheet" href="css/common.css">
</head>
<body>
    <div class="nav">
        <img src="image/2.png" alt="头像">
        <span class="title">我的博客系统</span>
        <a href="index.html">主页</a>
        <a href="personlist.html">个人主页</a>
        <a href="edit.html">创作</a>
        <a href="logout">注销</a>
    </div>
    <div class="parent">
        <div class="left">
            <div class="card">
                <img src="image/头像.jpg">
                <span class="name" th:text="${user.username}">蜡笔小新</span>
                <a href="#">github 地址</a>
                <div class='one'>
                  <span>文章</span>
                  <span>分类</span>
                </div>
                <div class='one'>
                  <span>2</span>
                  <span>1</span>
                </div>
              </div>
        </div>
        <div class="right">
            <div class="article" th:each="blog : ${blogs}">
                <h2 class="title" th:text="${blog.title}">我的第一篇博客</h2>
                <span class="date" th:text="${blog.postTime}">2022-4-17</span>
                <div class="desc" th:text="${blog.content}">.</div>
                <a th:href="${'details.html?blogId=' + blog.blogId}" class="more">查看全文&gt;&gt;</a>
            </div>
        </div>
    </div>
</body>
</html>

13.2 创建 PersonServlet

package View;

import Dao.Blog;
import Dao.BlogDao;
import Dao.User;
import Dao.UserDao;
import common.Util;
import org.thymeleaf.TemplateEngine;
import org.thymeleaf.context.WebContext;

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.List;

@WebServlet("/personlist.html")
public class PersonServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        resp.setContentType("text/html;charset=utf-8");
        User user = Util.checkLoginStatus(req);
        if(user == null){
            resp.sendRedirect("login.html");
            return;
        }

        BlogDao blogDao = new BlogDao();
        List<Blog> blogs = blogDao.selectAllPerson(user.getUserId());

        TemplateEngine engine = (TemplateEngine) getServletContext().getAttribute("engine");
        WebContext webContext = new WebContext(req,resp,getServletContext());
        webContext.setVariable("blogs",blogs);
        engine.process("personlist",webContext,resp.getWriter());
    }
}

14. 实现博客的编辑功能

14.1 修改博客详情页的前端代码

14.2 在数据中实现修改博客的操作

public void update(Blog blog){
        Connection connection = null;
        PreparedStatement statement = null;
        try {
            // 1. 建立连接
            connection = DBUtil.getConnection();
            // 2. 拼装 SQL 语句
            String sql = "update blog set content = ? ,title = ?,postTime = ? where blogId = ?";
            statement = connection.prepareStatement(sql);
            statement.setString(1,blog.getContent());
            statement.setString(2,blog.getTitle());
            statement.setTimestamp(3,blog.getPostTime());
            statement.setInt(4,blog.getBlogId());
            // 3. 执行 SQL 语句
            int ret = statement.executeUpdate();
            if(ret == 1){
                System.out.println("编辑成功");
            }else{
                System.out.println("编辑失败");
            }
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            DBUtil.close(connection,statement,null);
        }
    }

14.3 编写一个编辑的界面

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <link rel="stylesheet" href="css/common.css">
  <link rel="stylesheet" href="css/edit.css">
  <!-- 引入 editor.md 的依赖 -->
  <link rel="stylesheet" href="editor.md/css/editormd.min.css" />
  <script src="js/jquery.min.js"></script>
  <script src="editor.md/lib/marked.min.js"></script>
  <script src="editor.md/lib/prettify.min.js"></script>
  <script src="editor.md/editormd.js"></script>
</head>
<body>
<div class="nav">
  <img src="image/2.png" alt="头像">
  <span class="title">我的博客系统</span>
  <a href="index.html">主页</a>
  <a href="personlist.html">我的</a>
  <a href="edit.html">创作</a>
  <a href="logout">注销</a>
</div>
<div class="leader">
  <form th:action="${'update?blogId=' + blog.blogId}" method="post" style="height:100%">
    <div class="empOne">
      <input type="text" class="title" th:value="${blog.title}" name="title">
      <input type="submit" value="发布文章" class="publish">
    </div>
    <div id="editor">
      <textarea name="content" style="display:none;" th:text="${blog.content}"></textarea>
    </div>
  </form>
</div>

<script>
        // 初始化编辑器
        var editor = editormd("editor", {
            // 这里的尺寸必须在这里设置. 设置样式会被 editormd 自动覆盖掉.
            width: "100%",
            // 高度 100% 意思是和父元素一样高. 要在父元素的基础上去掉标题编辑区的高度
            height: "calc(100% - 75px)",
            // 指定 editor.md 依赖的插件路径
            path: "editor.md/lib/",
            saveHTMLToTextarea: true
        });
    </script>
</body>
</html>

14.4 实现 UpdateServlet

这里的 doget 请求是进入编辑页
dopost请求是提交编辑后的内容

package View;

import Dao.Blog;
import Dao.BlogDao;
import Dao.User;
import common.Util;
import org.thymeleaf.TemplateEngine;
import org.thymeleaf.context.WebContext;

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.sql.Timestamp;

@WebServlet("/update")
public class UpdateServlet extends HttpServlet{
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        resp.setContentType("text/html;charset=utf-8");
        String str = req.getParameter("blogId");
        if(str==null || "".equals(str)){
            resp.getWriter().write("<h3>博客Id不存在</h3>");
            return;
        }
        int blogId = Integer.parseInt(str);

        BlogDao blogDao = new BlogDao();
        Blog blog = blogDao.selectOne(blogId);
        if(blog == null){
            resp.getWriter().write("<h3>博文不存在</h3>");
            return;
        }
        TemplateEngine engine = (TemplateEngine) getServletContext().getAttribute("engine");
        WebContext webContext = new WebContext(req,resp,getServletContext());
        webContext.setVariable("blog",blog);

        engine.process("alter",webContext,resp.getWriter());
    }
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        resp.setContentType("text/html;charset=utf-8");
        req.setCharacterEncoding("utf-8");

        User user = Util.checkLoginStatus(req);
        if(user == null){
            resp.sendRedirect("login.html");
            return;
        }

        // 1. 获取参数
        String title = req.getParameter("title");
        String content = req.getParameter("content");
        String str = req.getParameter("blogId");
        if(str==null || "".equals(str)){
            System.out.println("blogId不存在");
            return;
        }
        int blogId = Integer.parseInt(str);
        // 2. 判断是否存在
        if(title==null || "".equals(title) || content==null || "".equals(content)){
            resp.getWriter().write("<h3>文章标题或者内容不存在</h3>");
            return;
        }

        // 插入到数据库中
        Blog blog = new Blog();
        blog.setContent(content);
        blog.setTitle(title);
        blog.setPostTime(new Timestamp(System.currentTimeMillis()));
        blog.setBlogId(blogId);
        BlogDao blogDao = new BlogDao();
        blogDao.update(blog);
        // 重定向
        resp.sendRedirect("personlist.html");
    }
}

版权说明 : 本文为转载文章, 版权归原作者所有 版权申明

原文链接 : https://wangzhi430.blog.csdn.net/article/details/124669731

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