• Java项目——博客系统（前后端交互）

    项目展示

    在这里插入图片描述
    在这里插入图片描述
    在这里插入图片描述
    在这里插入图片描述
    在这里插入图片描述

    项目说明

    使用servlet，实现前后端交互，通过jdbc和mysql数据库进行数据传输，使得可以将用户信息和博客列表存储在数据库中，实现真正的服务器，客户端，数据库三者的交互

    项目代码

    数据库

    在sql数据库中建立数据库，建立用户表和博客列表

    create database if not exists Lx_blog charset utf8mb4;
use Lx_blog;

drop table if exists blog;
create table blog (
    blogId int primary key auto_increment,
    title varchar(1024),
    content mediumtext,
    userId int,
    postTime datetime
);

insert into blog values(null,"这是第一篇博客", "从今天开始，我要一天写一篇博客",1,now());
insert into blog values(null,"这是第二篇博客", "从今天开始，我要一天写两篇博客",1,now());
insert into blog values(null,"这是第三篇博客", "从今天开始，我要一天写三篇博客",1,now());
insert into blog values(null,"这是第一篇博客", "从今天开始，我胡汉三要一天写一篇博客",2,now());
insert into blog values(null,"这是第一篇博客", "从昨天开始，我胡汉三要一天写两篇博客",2,now());
insert into blog values(null,"这是第三篇博客", "# 一级标题\n ### 三级标题\n > 引用内容",2,now());

drop table if exists user;
create table user (
    userId int primary key auto_increment,
    username varchar(128) unique,
    password varchar(128)
);

insert into user values(null, '123', 1234);
insert into user values(null, 'xiao', 8830);

    • 1
    • 2
    • 3
    • 4
    • 5
    • 6
    • 7
    • 8
    • 9
    • 10
    • 11
    • 12
    • 13
    • 14
    • 15
    • 16
    • 17
    • 18
    • 19
    • 20
    • 21
    • 22
    • 23
    • 24
    • 25
    • 26
    • 27
    • 28

    后端

    DBUtil

    实现jdbc的基础代码——获取DataSource的方法，获取connection的方法，close各种资源的方法

    package model;

import com.mysql.cj.jdbc.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/Lx_blog?characterEncoding=utf-8";
    private static final String USERNAME = "root";
	private static final String PASSWORD = "";

    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();
            }
        }
    }
}

    • 1
    • 2
    • 3
    • 4
    • 5
    • 6
    • 7
    • 8
    • 9
    • 10
    • 11
    • 12
    • 13
    • 14
    • 15
    • 16
    • 17
    • 18
    • 19
    • 20
    • 21
    • 22
    • 23
    • 24
    • 25
    • 26
    • 27
    • 28
    • 29
    • 30
    • 31
    • 32
    • 33
    • 34
    • 35
    • 36
    • 37
    • 38
    • 39
    • 40
    • 41
    • 42
    • 43
    • 44
    • 45
    • 46
    • 47
    • 48
    • 49
    • 50
    • 51
    • 52
    • 53
    • 54
    • 55
    • 56
    • 57
    • 58
    • 59

    Blog

    是博客列表中每一个博客对象，里面包含博客id，标题，内容，用户id，提交时间，及一系列get和set方法

    package model;

import java.sql.Timestamp;
import java.text.SimpleDateFormat;

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

    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 int getUserId() {
        return userId;
    }

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

//    public Timestamp getPostTime() {
//        return postTime;
//    }

    public String getPostTime(){
        SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        return simpleDateFormat.format(postTime);
    }

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

    • 1
    • 2
    • 3
    • 4
    • 5
    • 6
    • 7
    • 8
    • 9
    • 10
    • 11
    • 12
    • 13
    • 14
    • 15
    • 16
    • 17
    • 18
    • 19
    • 20
    • 21
    • 22
    • 23
    • 24
    • 25
    • 26
    • 27
    • 28
    • 29
    • 30
    • 31
    • 32
    • 33
    • 34
    • 35
    • 36
    • 37
    • 38
    • 39
    • 40
    • 41
    • 42
    • 43
    • 44
    • 45
    • 46
    • 47
    • 48
    • 49
    • 50
    • 51
    • 52
    • 53
    • 54
    • 55
    • 56
    • 57

    User

    用户对象，其包括用户id，用户名和密码，及一系列get和set方法

    package model;

public class User {
    private int userId = 0;
    private String username = "";
    private 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;
    }
}


    • 1
    • 2
    • 3
    • 4
    • 5
    • 6
    • 7
    • 8
    • 9
    • 10
    • 11
    • 12
    • 13
    • 14
    • 15
    • 16
    • 17
    • 18
    • 19
    • 20
    • 21
    • 22
    • 23
    • 24
    • 25
    • 26
    • 27
    • 28
    • 29
    • 30
    • 31
    • 32

    BlogDao

    通过调用jdbc中的一系列查询和插入方法，实现新增博客，获取所有博客，通过博客id获取单一博客的方法

    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 {
    public void insert(Blog blog){
        Connection connection = null;
        PreparedStatement statement = null;
        try {
            connection = DBUtil.getConnection();
            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());

            statement.executeUpdate();

        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            DBUtil.close(connection,statement,null);
        }
    }

    public List<Blog> selectAll(){
        List<Blog> 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();
            while(resultSet.next()){
                Blog blog = new Blog();
                blog.setBlogId(resultSet.getInt("blogId"));
                blog.setTitle(resultSet.getString("title"));
                String content = resultSet.getString("content");
                if(content.length() > 50){
                    content = content.substring(0, 50) + "...";
                }
                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;
    }

    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();
            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;
    }

    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);
        }
    }
}

    • 1
    • 2
    • 3
    • 4
    • 5
    • 6
    • 7
    • 8
    • 9
    • 10
    • 11
    • 12
    • 13
    • 14
    • 15
    • 16
    • 17
    • 18
    • 19
    • 20
    • 21
    • 22
    • 23
    • 24
    • 25
    • 26
    • 27
    • 28
    • 29
    • 30
    • 31
    • 32
    • 33
    • 34
    • 35
    • 36
    • 37
    • 38
    • 39
    • 40
    • 41
    • 42
    • 43
    • 44
    • 45
    • 46
    • 47
    • 48
    • 49
    • 50
    • 51
    • 52
    • 53
    • 54
    • 55
    • 56
    • 57
    • 58
    • 59
    • 60
    • 61
    • 62
    • 63
    • 64
    • 65
    • 66
    • 67
    • 68
    • 69
    • 70
    • 71
    • 72
    • 73
    • 74
    • 75
    • 76
    • 77
    • 78
    • 79
    • 80
    • 81
    • 82
    • 83
    • 84
    • 85
    • 86
    • 87
    • 88
    • 89
    • 90
    • 91
    • 92
    • 93
    • 94
    • 95
    • 96
    • 97
    • 98
    • 99
    • 100
    • 101
    • 102
    • 103
    • 104

    UserDao

    通过jdbc中的查询和增加方法，实现通过用户名查询用户和根据用户id查询用户

    package model;

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

public class UserDao {
    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();

            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;
    }

    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();

            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;
    }
}


    • 1
    • 2
    • 3
    • 4
    • 5
    • 6
    • 7
    • 8
    • 9
    • 10
    • 11
    • 12
    • 13
    • 14
    • 15
    • 16
    • 17
    • 18
    • 19
    • 20
    • 21
    • 22
    • 23
    • 24
    • 25
    • 26
    • 27
    • 28
    • 29
    • 30
    • 31
    • 32
    • 33
    • 34
    • 35
    • 36
    • 37
    • 38
    • 39
    • 40
    • 41
    • 42
    • 43
    • 44
    • 45
    • 46
    • 47
    • 48
    • 49
    • 50
    • 51
    • 52
    • 53
    • 54
    • 55
    • 56
    • 57
    • 58
    • 59
    • 60
    • 61

    BlogServlet

    实现get方法，以json的数据格式返回数据，如果参数中没有blogid，则返回所有博客的信息，如果有blogid则返回对应的一篇博客

    实现post方法，先通过session中数据判断是否登陆，若未登陆则强制要求登陆，再判断前端传输过来的的博客是否有题目和内容，若没有则返回，若符合规范，则调用BlogDao中的插入方法，将新的博客插入到数据库中

    package controller;

import com.fasterxml.jackson.databind.ObjectMapper;
import model.Blog;
import model.BlogDao;
import model.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 javax.servlet.http.HttpSession;
import java.io.IOException;
import java.util.List;

@WebServlet("/blog")
public class BlogServlet extends HttpServlet {
    private ObjectMapper objectMapper = new ObjectMapper();
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        resp.setContentType("application/json; charset=utf8");
        String param = req.getParameter("blogId");
        BlogDao blogDao = new BlogDao();
        if(param == null){
            //博客列表
            List<Blog> blogs = blogDao.selectAll();
            String respJson = objectMapper.writeValueAsString(blogs);
            resp.getWriter().write(respJson);
        } else {
            //博客详情
            int blogId = Integer.parseInt(param);
            Blog blog = blogDao.selectOne(blogId);
            String respJson = objectMapper.writeValueAsString(blog);
            resp.getWriter().write(respJson);
        }
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        HttpSession session = req.getSession(false);
        if(session == null){
            resp.setContentType("text/html;charset=utf8");
            resp.getWriter().write("当前用户未登陆，请登陆后提交博客");
            return;
        }

        User user = (User) session.getAttribute("user");
        if(user == null){
            resp.setContentType("text/html;charset=utf8");
            resp.getWriter().write("当前用户未登陆，请登陆后提交博客");
            return;
        }

        req.setCharacterEncoding("utf8");
        String title = req.getParameter("title");
        String content = req.getParameter("content");

        if(title == null || title.equals("") || content == null || content.equals("")){
            resp.setContentType("text/html;charset=utf8");
            resp.getWriter().write("提交博客失败，缺少参数");
            return;
        }

        Blog blog = new Blog();
        blog.setTitle(title);
        blog.setContent(content);
        blog.setUserId(user.getUserId());
        BlogDao blogDao = new BlogDao();
        blogDao.insert(blog);

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


    • 1
    • 2
    • 3
    • 4
    • 5
    • 6
    • 7
    • 8
    • 9
    • 10
    • 11
    • 12
    • 13
    • 14
    • 15
    • 16
    • 17
    • 18
    • 19
    • 20
    • 21
    • 22
    • 23
    • 24
    • 25
    • 26
    • 27
    • 28
    • 29
    • 30
    • 31
    • 32
    • 33
    • 34
    • 35
    • 36
    • 37
    • 38
    • 39
    • 40
    • 41
    • 42
    • 43
    • 44
    • 45
    • 46
    • 47
    • 48
    • 49
    • 50
    • 51
    • 52
    • 53
    • 54
    • 55
    • 56
    • 57
    • 58
    • 59
    • 60
    • 61
    • 62
    • 63
    • 64
    • 65
    • 66
    • 67
    • 68
    • 69
    • 70
    • 71
    • 72
    • 73
    • 74
    • 75

    BlogDeleteServlet

    实现get方法，先判定用户是否登陆，再判断博客中的参数是否存在，判断博客的用户id和用户的id是否一致（判断是否操作者为文章作者），全部确定为真时，调用BlogDao中的blogDelete方法，实现博客的删除功能

    package controller;

import model.Blog;
import model.BlogDao;
import model.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 javax.servlet.http.HttpSession;
import java.io.IOException;

@WebServlet("/blogDelete")
public class BlogDeleteServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        HttpSession session = req.getSession(false);
        if(session == null){
            resp.setContentType("text/html; charset=utf8");
            resp.getWriter().write("当前尚未登录，无法删除!!");
            return;
        }

        User user = (User) session.getAttribute("user");
        if(user == null){
            resp.setContentType("text/html; charset=utf8");
            resp.getWriter().write("当前尚未登录，无法删除!!");
            return;
        }

        String blogId = req.getParameter("blogId");
        if(blogId == null || blogId.equals("")){
            resp.setContentType("text/html; charset=utf8");
            resp.getWriter().write("当前blogId参数错误!!");
            return;
        }

        BlogDao blogDao = new BlogDao();
        Blog blog = blogDao.selectOne(Integer.parseInt(blogId));
        if(blog == null){
            resp.setContentType("text/html; charset=utf8");
            resp.getWriter().write("当前要删除的博客不存在!!");
            return;
        }

        if(user.getUserId() != blog.getUserId()){
            resp.setContentType("text/html; charset=utf8");
            resp.getWriter().write("当前登陆用户无访问权限!!");
            return;
        }

        blogDao.delete(Integer.parseInt(blogId));
        resp.sendRedirect("blogList.html");
    }
}


    • 1
    • 2
    • 3
    • 4
    • 5
    • 6
    • 7
    • 8
    • 9
    • 10
    • 11
    • 12
    • 13
    • 14
    • 15
    • 16
    • 17
    • 18
    • 19
    • 20
    • 21
    • 22
    • 23
    • 24
    • 25
    • 26
    • 27
    • 28
    • 29
    • 30
    • 31
    • 32
    • 33
    • 34
    • 35
    • 36
    • 37
    • 38
    • 39
    • 40
    • 41
    • 42
    • 43
    • 44
    • 45
    • 46
    • 47
    • 48
    • 49
    • 50
    • 51
    • 52
    • 53
    • 54
    • 55
    • 56
    • 57
    • 58

    AuthorServlet

    实现get方法，判断是否传输了blogid，判断blogid在数据库中是否存在，然后通过这个blogid，调用blogDao中的select方法，拿到blog对象，将密码设置为空（保护用户隐私），然后将用户信息以json格式传输给后端

    package controller;

import com.fasterxml.jackson.databind.ObjectMapper;
import model.Blog;
import model.BlogDao;
import model.User;
import model.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("/authorInfo")
public class AuthorServlet extends HttpServlet {
    private ObjectMapper objectMapper = new ObjectMapper();
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        resp.setContentType("application/json; charset=utf8");
        String param = req.getParameter("blogId");
        if(param == null || param.equals("")){
            resp.getWriter().write("{\"ok\": false, \"reason \": \"参数缺失！\"}");
            return;
        }

        BlogDao blogDao = new BlogDao();
        Blog blog = blogDao.selectOne(Integer.parseInt(param));
        if(blog == null){
            resp.getWriter().write("{\"ok\": false, \"reason \": \"查询的博客不存在！\"}");
            return;
        }

        UserDao userDao = new UserDao();
        User author = userDao.selectById(blog.getUserId());
        if(author == null){
            resp.getWriter().write("{\"ok\": false, \"reason \": \"查询的用户不存在！\"}");
            return;
        }

        author.setPassword("");
        resp.getWriter().write(objectMapper.writeValueAsString(author));
    }
}


    • 1
    • 2
    • 3
    • 4
    • 5
    • 6
    • 7
    • 8
    • 9
    • 10
    • 11
    • 12
    • 13
    • 14
    • 15
    • 16
    • 17
    • 18
    • 19
    • 20
    • 21
    • 22
    • 23
    • 24
    • 25
    • 26
    • 27
    • 28
    • 29
    • 30
    • 31
    • 32
    • 33
    • 34
    • 35
    • 36
    • 37
    • 38
    • 39
    • 40
    • 41
    • 42
    • 43
    • 44
    • 45
    • 46

    LoginServlet

    实现post方法，获取前端传输的用户名和密码，判断是否符合规范，用UserDao中的select方法查询用户是否存在，如果存在则用user对象构造session，最后重定向到blogList.html

    实现get方法，获取sessoin，将其转换为user对象，然后将其以json数据格式传输给前端

    package controller;

import com.fasterxml.jackson.databind.ObjectMapper;
import model.User;
import model.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 {
    private ObjectMapper objectMapper = new ObjectMapper();
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        req.setCharacterEncoding("utf8");
        resp.setCharacterEncoding("utf8");
        String username = req.getParameter("username");
        String password = req.getParameter("password");
        if(username == null || username.equals("") || password == null || password.equals("")) {
            resp.setContentType("text/html; charset=utf8");
            resp.getWriter().write("输入用户名/密码为空！！！");
            return;
        }
        UserDao userDao = new UserDao();
        User user = userDao.selectByName(username);
        if(user == null || !user.getPassword().equals(password)){
            resp.setContentType("text/html; charset=utf8");
            resp.getWriter().write("用户名不存在/密码错误！！！");
            return;
        }

        HttpSession session = req.getSession(true);
        session.setAttribute("user",user);

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

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        resp.setContentType("application/json;charset=utf8");
        HttpSession session = req.getSession(false);
        if(session == null){
            User user = new User();
            resp.getWriter().write(objectMapper.writeValueAsString(user));
            return;
        }
        User user = (User) session.getAttribute("user");
        if(user == null){
            user = new User();
            resp.getWriter().write(objectMapper.writeValueAsString(user));
            return;
        }
        user.setPassword("");
        resp.getWriter().write(objectMapper.writeValueAsString(user));
    }
}


    • 1
    • 2
    • 3
    • 4
    • 5
    • 6
    • 7
    • 8
    • 9
    • 10
    • 11
    • 12
    • 13
    • 14
    • 15
    • 16
    • 17
    • 18
    • 19
    • 20
    • 21
    • 22
    • 23
    • 24
    • 25
    • 26
    • 27
    • 28
    • 29
    • 30
    • 31
    • 32
    • 33
    • 34
    • 35
    • 36
    • 37
    • 38
    • 39
    • 40
    • 41
    • 42
    • 43
    • 44
    • 45
    • 46
    • 47
    • 48
    • 49
    • 50
    • 51
    • 52
    • 53
    • 54
    • 55
    • 56
    • 57
    • 58
    • 59
    • 60
    • 61
    • 62

    LogoutServlet

    实现get方法，拿到session，通过是否为空判断用户是否登陆，如果登陆了，则移除该session，然后重定向到login.html

    package controller;

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 {
        HttpSession session = req.getSession(false);
        if(session == null){
            resp.getWriter().write("当前用户尚未登录，无法注销！");
            return;
        }
        session.removeAttribute("user");
        resp.sendRedirect("login.html");
    }
}


    • 1
    • 2
    • 3
    • 4
    • 5
    • 6
    • 7
    • 8
    • 9
    • 10
    • 11
    • 12
    • 13
    • 14
    • 15
    • 16
    • 17
    • 18
    • 19
    • 20
    • 21
    • 22
    • 23
    • 24

    前端代码

    在之前的博客中有前端的代码，改动的地方如下

    common.js

    实现changeUserName的方法，获取页面左侧的用户名对应的h3标签，将其内容设置为当前登陆的用户的用户名

    实现getUserInfo方法，参数是页名，类型是get方法，url是login，对应LoginServlet中的get方法。其功能是判断用户是否曾路，如果登陆了，就调用changeUserName方法，传输用户的名字

    function getUserInfo(pageName){
    $.ajax({
        type: 'GET',
        url: 'login',
        success: function(body) {
            if(body.userId && body.userId > 0){
                console.log("登录成功！ 用户名：" + body.username);
                if(pageName == 'blogList.html'){
                    changeUserName(body.username);
                }
            } else {
                alert("当前未登陆！！！");
                location.assign('login.html');
            }
        },
        error: function(){
            alert("当前未登陆！！！");
            location.assign('login.html');
        }
    });
}

function changeUserName(username){
    let h3 = document.querySelector('.card>h3');
    h3.innerHTML = username;
}

    • 1
    • 2
    • 3
    • 4
    • 5
    • 6
    • 7
    • 8
    • 9
    • 10
    • 11
    • 12
    • 13
    • 14
    • 15
    • 16
    • 17
    • 18
    • 19
    • 20
    • 21
    • 22
    • 23
    • 24
    • 25
    • 26

    login.html

    用户名，密码，提交按钮用form表单包裹，action是login，对应LoginServlet，method则是post方法，将用户名，密码增加id属性，并且将提交改成submit

    <form action="login" method="POST">
    <div class="row">
        <span>用户名span>
        <input type="text" id = 'username' name = 'username'>
    div>
    <div class="row">
        <span>密码span>
        <input type="password" id = 'password' name = 'password'>
    div>
    <div class="row submitRow">
        
        <input type="submit" id = "submit" value = "提交">
    div>
form>

    • 1
    • 2
    • 3
    • 4
    • 5
    • 6
    • 7
    • 8
    • 9
    • 10
    • 11
    • 12
    • 13
    • 14

    blogList.html

    <script>
        function getBlogList(){
            $.ajax({
                type: 'get',
                url: 'blog',
                success: function(body) {
                    let rightDiv = document.querySelector('.right');
                    rightDiv.innerHTML = "";
                    for(let blog of body){
                        //blog
                        let blogDiv = document.createElement('div');
                        blogDiv.className = 'blog';
                        //标题
                        let titleDiv = document.createElement('div');
                        titleDiv.className = 'title';
                        titleDiv.innerHTML =blog.title;
                        blogDiv.appendChild(titleDiv);
                        //发布时间
                        let dateDiv = document.createElement('div');
                        dateDiv.className = 'date';
                        dateDiv.innerHTML =blog.postTime;
                        blogDiv.appendChild(dateDiv);
                        //摘要
                        let descDiv = document.createElement('div');
                        descDiv.className = 'summary';
                        descDiv.innerHTML =blog.content;
                        blogDiv.appendChild(descDiv);
                        //查看全文
                        let a = document.createElement('a');
                        a.className = 'detail'
                        a.innerHTML = '查看全文 >>';
                        a.href = 'blogDetail.html?blogId=' + blog.blogId;
                        blogDiv.appendChild(a);

                        rightDiv.appendChild(blogDiv);
                    }
                },
                error: function(){
                    alert("获取博客失败!!!");
                }
            });
        }

        getBlogList();
    script>
    <script src="js/common.js">script>

    <script>
        getUserInfo('blogList.html');
    script>

    • 1
    • 2
    • 3
    • 4
    • 5
    • 6
    • 7
    • 8
    • 9
    • 10
    • 11
    • 12
    • 13
    • 14
    • 15
    • 16
    • 17
    • 18
    • 19
    • 20
    • 21
    • 22
    • 23
    • 24
    • 25
    • 26
    • 27
    • 28
    • 29
    • 30
    • 31
    • 32
    • 33
    • 34
    • 35
    • 36
    • 37
    • 38
    • 39
    • 40
    • 41
    • 42
    • 43
    • 44
    • 45
    • 46
    • 47
    • 48
    • 49
    • 50

    blogEdit.html

    将script中加入saveHTMLToTextarea: true的属性，将html中的标题，发布按钮和内容改成下面对应的格式，外面使用form表单包裹，action是blog，方法是post，对应BlogServlet中的post方法，实现博客编辑后提交给服务器，服务器传输给数据库的功能

    <form action="blog" method="POST" style="height:100%">
    <div class="title">
        <input type="text" placeholder = "在此输入标题" id = 'title' name = "title">
        <input type="submit" value="发布文章" id="submit">
    div>

    <div id="editor">
        <textarea name="content" style="display:none;">textarea>
    div>
form>

    • 1
    • 2
    • 3
    • 4
    • 5
    • 6
    • 7
    • 8
    • 9
    • 10
    <script>
    var editor = editormd("editor", {
        width:"100%",
        height:"calc(100% - 80px)",
        markdown:"# 在这里写下一篇博客",
        path:"editor.md/lib/",
        saveHTMLToTextarea: true
    });
script>

    • 1
    • 2
    • 3
    • 4
    • 5
    • 6
    • 7
    • 8
    • 9

    blogDetail.html

    用ajax实现getBlogDetail方法，类型为get，url为blog+location.search，对应后端的BlogServlet中的get方法，实现通过blogid获取blog对象功能，成功时将后端传输过来的blog对象中的题目，时间，内容等添加到dom树上

    用ajax实现getAuthorInfo的方法，类型为get，url为authorInfo+location.search，对应AuthorServlet中的get方法，从前端获得登陆的用户信息，如果登陆的用户和文章的用户名相同，代表这个人可以删除自己的文章，在dom树上加删除的a标签，a标签中是blogDelete + location.search，对应后端的BlogDeleteServlet，实现将文章id传输给后端，后端让数据库删除该文章的操作

    用ajax实现getUserInfo功能，大体功能和common.js中的getUserInfo功能大体相同，只是在其中调用getAuthorInfo方法

    <script>
        function getBlogDetail(){
            $.ajax({
                type: 'get',
                url: 'blog' + location.search,
                success: function(body){
                    let h3 = document.querySelector(".blogContainer>h3");
                    h3.innerHTML = body.title;
                    let dateDiv = document.querySelector('.date');
                    dateDiv.innerHTML = body.postTime;
                    editormd.markdownToHTML('content', {
                        markdown: body.content
                    });
                }
            });
        }
        getBlogDetail();

        function getUserInfo(pageName){
            $.ajax({
                type: 'GET',
                url: 'login',
                success: function(body) {
                    if(body.userId && body.userId > 0){
                        console.log("登录成功！ 用户名：" + body.username);
                        getAuthorInfo(body);
                    } else {
                        alert("当前未登陆！！！");
                        location.assign('login.html');
                    }
                },
                error: function(){
                    alert("当前未登陆！！！");
                    location.assign('login.html');
                }
            });
        }

        getUserInfo('blogDetail.html');

        function getAuthorInfo(user){
            $.ajax({
                type: 'GET',
                url: 'authorInfo' + location.search,
                success: function(body){
                    if(body.username){
                        changeUserName(body.username);

                        if(body.username == user.username){
                            let navDiv = document.querySelector('.nav');
                            let a = document.createElement('a');
                            a.innerHTML = '删除';
                            a.href = 'blogDelete' + location.search;
                            navDiv.appendChild(a);
                        }
                    } else {
                        console.log("获取作者信息失败!!!" + body.reason);
                    }
                }
            });
        }

        function changeUserName(username){
            let h3 = document.querySelector('.card>h3');
            h3.innerHTML = username;
        }
    script>

    • 1
    • 2
    • 3
    • 4
    • 5
    • 6
    • 7
    • 8
    • 9
    • 10
    • 11
    • 12
    • 13
    • 14
    • 15
    • 16
    • 17
    • 18
    • 19
    • 20
    • 21
    • 22
    • 23
    • 24
    • 25
    • 26
    • 27
    • 28
    • 29
    • 30
    • 31
    • 32
    • 33
    • 34
    • 35
    • 36
    • 37
    • 38
    • 39
    • 40
    • 41
    • 42
    • 43
    • 44
    • 45
    • 46
    • 47
    • 48
    • 49
    • 50
    • 51
    • 52
    • 53
    • 54
    • 55
    • 56
    • 57
    • 58
    • 59
    • 60
    • 61
    • 62
    • 63
    • 64
    • 65
    • 66
    • 67
  • 相关阅读:
    Java中对索引的知识总结
    计算机缺失pasmutility.dll怎么办，三步解决pasmutility.dll缺失
    RabbitMQ3.13.x之十二_WindowsServer服务器安装RabbitMQ后无法连接问题及处理方法
    B. Moderate Modular Mode(nmodx=ymodn )
    jwt 保证前端刷新不掉线
    注释Java
    Kali中安装和使用docker的学习笔记
    java毕业设计LIS检验系统2021mybatis+源码+调试部署+系统+数据库+lw
    设计模式与应用：迭代器模式
    使用腾讯云 Cloud studio 实现调度百度AI实现文字识别
  • 原文地址：https://blog.csdn.net/m0_60867520/article/details/128065580