博客管理系统--项目说明

• 项目体验地址（账号：123，密码：123）http://120.53.20.213:8080/blog_system/login.html

• 项目码云Gitee地址：https://gitee.com/GoodManSS/project/tree/master/blog_system

（一）准备工作

因为是一个简单的博客系统，所以软件开发的基本流程这里我们就简要一些，主要分为 需求分析，数据库设计

1. 需求分析

① 实现博客列表的展示功能

② 实现博客详情的展示功能

③ 登录功能

• login登录页面

• 注册页面

④ 限制用户权限（强制要求用户登录）

⑤ 显示用户的信息

• 文章详情页显示信息

• 用户能够修改个人资料，如头像，昵称，Gitee地址

⑥ 实现注销（退出账号功能）

⑦ 发布博客

⑧ 删除博客

2.数据库设计

① 博客表blog

• blogId（Id）自增主键

• title（文章标题）

• content(文章内容） 类型：text 最大64k

• postTime（发布时间）

• userId（文章所属用户）

② 用户表user

• useId（ID/账号）

• passWord（登录密码）

• userName（昵称)

• head（头像） 这里采用保存头像路径的方式

• Gitee地址

③ 代码

// 1.创建一个库
create database if not exists blog_system;
use blog_system;
// 2.创建blog表
drop table if exists blog;
create table blog(blogId int primary key auto_increment,title varchar(256),content text,postTime datetime,userId varchar(50)
);
// 3.创建user表
drop table if exists user;
create table user(userId varchar(50) primary key,userName varchar(50),passWord varchar(50),gitDress varchar(50),head varchar(100)
);

3.引入依赖

博客管理系统，必不可获取的有Servlet，mysql，Jackson，还有编辑页要使用到Markdown语法

<dependencies><!-- mysql的依赖 --><dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId><version>5.1.47</version></dependency><!-- servlet的依赖 --><dependency><groupId>javax.servlet</groupId><artifactId>javax.servlet-api</artifactId><version>3.1.0</version><scope>provided</scope></dependency><!-- Jackson的依赖 --><dependency><groupId>com.fasterxml.jackson.core</groupId><artifactId>jackson-databind</artifactId><version>2.13.1</version></dependency>
</dependencies>

4.引入前端代码

① 在main目录下新建一个webapp文件夹。

② 把前段的代码复制粘贴到这个目录

③ 加入WEB-INF\web.xml文件内容

④ 最终目录截图

（二）写后端代码

1. 连接数据库DBUtil

连接数据库 使用单例模式的 懒汉模式实现

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 volatile DataSource dataSource = null;public static DataSource getDataSource() {if (dataSource == null) {synchronized (DBUtil.class) {if (dataSource == null) {dataSource = new MysqlDataSource();((MysqlDataSource) dataSource).setURL("jdbc:mysql://127.0.0.1:3306/blog_system?characterEncoding=utf8&useSSL=false");((MysqlDataSource) dataSource).setUser("root");((MysqlDataSource) dataSource).setPassword("SHANhaonan521");}}}return dataSource;}//与数据库进行连接public static Connection getConnection() throws SQLException {return getDataSource().getConnection();}//关闭连接public static void close(Connection connection, PreparedStatement preparedStatement, ResultSet resultSet) {if (resultSet != null) {try {resultSet.close();} catch (SQLException e) {throw new RuntimeException(e);}}if (preparedStatement != null) {try {preparedStatement.close();} catch (SQLException e) {throw new RuntimeException(e);}}if (connection != null) {try {connection.close();} catch (SQLException e) {throw new RuntimeException(e);}}}}

2.Blog和User类

两个类对应数据库的两个表

① Blog类

不仅要有get set方法，还要有一个compareTo，用来对文章进行排序（按照发布时间）

import java.sql.Timestamp;
import java.text.SimpleDateFormat;public class Blog implements Comparable<Blog> {private int blogId;private String title;private String content;private Timestamp postTime;private String 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 String getPostTime() {SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy年MM月dd日 hh:mm");return simpleDateFormat.format(postTime);}public void setPostTime(Timestamp postTime) {this.postTime = postTime;}public String getUserId() {return userId;}public void setUserId(String userId) {this.userId = userId;}//这是一个排序方法@Overridepublic int compareTo(Blog o) {return this.getPostTime().compareTo(o.getPostTime());}
}

② User类

public class User {private String userId;private String userName;private String passWord;private String gitDress;private String head;public String getUserId() {return userId;}public void setUserId(String 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;}public String getHead() {return head;}public void setHead(String head) {this.head = head;}public String getGitDress() {return gitDress;}public void setGitDress(String gitDress) {this.gitDress = gitDress;}
}

③ BlogAndUserVO

在博客详情页，不仅要显示博客的相关信息，还要有一些作者的信息，加入一个VO类来实现这一功能

public class BlogAndUserVO {private int blogId;private String title;private String content;private String postTime;private String userId;private String userName;private String head;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 String getPostTime() {return postTime;}public void setPostTime(String postTime) {this.postTime = postTime;}public String getUserId() {return userId;}public void setUserId(String userId) {this.userId = userId;}public String getUserName() {return userName;}public void setUserName(String userName) {this.userName = userName;}public String getHead() {return head;}public void setHead(String head) {this.head = head;}
}

3.BlogDao和UserDao

BlogDao 和 UserDao主要功能就是和数据库建立连接，实现对数据库的增删查改。

① BLogDao

实现了增加博客，删除博客，查找博客，查找所有博客四个方法

    import java.sql.*;import java.text.SimpleDateFormat;import java.util.ArrayList;import java.util.Comparator;import java.util.List;public class BlogDao {// 1.增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.setString(3, blog.getUserId());int n = statement.executeUpdate();SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy年MM月dd日 hh:mm");if (n == 1) {System.out.println(simpleDateFormat.format(System.currentTimeMillis()));System.out.println("新增博客成功  title:"+blog.getTitle());} else {System.out.println(simpleDateFormat.format(System.currentTimeMillis()));System.out.println("新增博客失败");}} catch (SQLException e) {e.printStackTrace();} finally {DBUtil.close(connection, statement, null);}}// 2.删---通过主键blogId删除public void deleteOneByBlogId(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);int n = statement.executeUpdate();SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy年MM月dd日 hh:mm");System.out.println(simpleDateFormat.format(System.currentTimeMillis()));if (n == 1) {System.out.println("删除博客成功  blogId:"+blogId);} else {System.out.println("删除博客失败");}} catch (SQLException e) {e.printStackTrace();} finally {DBUtil.close(connection, statement, null);}}// 3.查--通过BlogId查询博客public Blog selectOneByBlogId(int blogId) {Blog blog = new Blog();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.setBlogId(resultSet.getInt("blogId"));blog.setTitle(resultSet.getString("title"));blog.setContent(resultSet.getString("content"));blog.setPostTime(Timestamp.valueOf(resultSet.getString("postTime")));blog.setUserId(resultSet.getString("userId"));}} catch (SQLException e) {e.printStackTrace();} finally {DBUtil.close(connection, statement, resultSet);}return blog;}//3. 查找所有的博客--排序好的主要是为了显示主页面public List<Blog> selectAllBlog() {Connection connection = null;PreparedStatement statement = null;ResultSet resultSet = null;List<Blog> list = new ArrayList<>();try {connection = DBUtil.getConnection();String sql = "select * from blog";statement = connection.prepareStatement(sql);resultSet = statement.executeQuery();while (resultSet.next()) {Blog blog = new Blog();blog.setBlogId(resultSet.getInt("blogId"));blog.setTitle(resultSet.getString("title"));blog.setContent(resultSet.getString("content"));blog.setPostTime(Timestamp.valueOf(resultSet.getString("postTime")));blog.setUserId(resultSet.getString("userId"));list.add(blog);}//进行时间排序list.sort(new Comparator<Blog>() {@Overridepublic int compare(Blog o1, Blog o2) {return o1.getPostTime().compareTo(o2.getPostTime());}});} catch (SQLException e) {e.printStackTrace();} finally {DBUtil.close(connection, statement, resultSet);}return list;}}

② UserDao

四个方法，分别是增删查改

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.text.SimpleDateFormat;public class UserDao {// 1.增public void insert(User user) {Connection connection = null;PreparedStatement statement = null;try {connection = DBUtil.getConnection();String sql = "insert into user values(?,?,?,?,?)";statement = connection.prepareStatement(sql);statement.setString(1, user.getUserId());statement.setString(2, user.getUserName());statement.setString(3, user.getPassWord());statement.setString(4, user.getHead());statement.setString(5, user.getGitDress());int n = statement.executeUpdate();if (n == 1) {System.out.println("新增数据成功！");} else {System.out.println("新增失败！");}} catch (SQLException e) {e.printStackTrace();} finally {DBUtil.close(connection, statement, null);}}// 2.删public void deleteOne(User user) {Connection connection = null;PreparedStatement statement = null;try {connection = DBUtil.getConnection();String sql = "delete from user where userId = ?";statement = connection.prepareStatement(sql);statement.setString(1, user.getUserId());int n = statement.executeUpdate();SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy年MM月dd日 hh:mm");System.out.println(simpleDateFormat.format(System.currentTimeMillis()));if (n == 1) {System.out.println("注销成功  user:" + user.getUserName());} else {System.out.println("注销失败");}} catch (SQLException e) {throw new RuntimeException(e);} finally {DBUtil.close(connection, statement, null);}}// 3.查--根据UserIdpublic User selectOneByUserId(String userId) {Connection connection = null;PreparedStatement statement = null;ResultSet resultSet = null;User user = null;try {connection = DBUtil.getConnection();String sql = "select * from user where userId = ?";statement = connection.prepareStatement(sql);statement.setString(1, userId);resultSet = statement.executeQuery();user = new User();if (resultSet.next()) {user.setUserId(resultSet.getString("userId"));user.setUserName(resultSet.getString("userName"));user.setPassWord(resultSet.getString("passWord"));user.setHead(resultSet.getString("header"));user.setGitDress(resultSet.getString("gitee"));}} catch (SQLException e) {e.printStackTrace();} finally {DBUtil.close(connection, statement, resultSet);}return user;}// 4.改--个人资料修改public void update(User user) {Connection connection = null;PreparedStatement statement = null;try {connection = DBUtil.getConnection();String sql = "update user set gitee=?,userName=? where userId=?";statement = connection.prepareStatement(sql);statement.setString(1, user.getGitDress());statement.setString(2, user.getUserName());statement.setString(3, user.getUserId());int n = statement.executeUpdate();if (n == 1) {System.out.println("update 成功");} else {System.out.println("update 失败");}} catch (SQLException e) {e.printStackTrace();} finally {DBUtil.close(connection, statement, null);}}
}

2. Servlet类

Servlet类主要就是通过@WebServlet注解来实现前后端信息的交互，前端发送请求后，都端实现对数据库的增删查改功能

① "blog"显示/增加博客

doGet：get实现两个功能，当传入blogId的时候显示博客详情页，当没有的时候显示博客列表页。
doPost：增加一个新博客

import com.fasterxml.jackson.databind.ObjectMapper;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 ServletBlog extends HttpServlet {@Overrideprotected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {resp.setContentType("application/json;charset=utf8");String blogId = req.getParameter("blogId");BlogDao blogDao = new BlogDao();UserDao userDao = new UserDao();ObjectMapper objectMapper = new ObjectMapper();if (blogId == null) {//返回博客列表List<Blog> list = blogDao.selectAllBlog();for (Blog blog : list) {if (blog.getContent().length() > 100) {blog.setContent(blog.getContent().substring(0, 145));}}resp.getWriter().write(objectMapper.writeValueAsString(list));} else {//返回博客详情  使用VO类//1.把 blog的内容加入到这个类中Blog blog = blogDao.selectOneByBlogId(Integer.parseInt(blogId));BlogAndUserVO blogAndUserVO = new BlogAndUserVO();blogAndUserVO.setBlogId(blog.getBlogId());blogAndUserVO.setPostTime(blog.getPostTime());blogAndUserVO.setTitle(blog.getTitle());blogAndUserVO.setContent(blog.getContent());//把user的内容加入到这个类User user = userDao.selectOneByUserId(blog.getUserId());blogAndUserVO.setUserName(user.getUserName());blogAndUserVO.setUserId(user.getUserId());blogAndUserVO.setHead(user.getHead());//返回VO类resp.getWriter().write(objectMapper.writeValueAsString(blogAndUserVO));}}@Overrideprotected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {req.setCharacterEncoding("utf8");resp.setContentType("text/html;charset=utf8");// 1.要先检查一下用户的登录状态HttpSession session = req.getSession();if (session == null) {resp.setStatus(403);resp.getWriter().write("当前未登录");return;}User user = (User) session.getAttribute("user");if (user == null) {resp.setStatus(403);resp.getWriter().write("当前未登录");return;}// 2.获取请求的参数String title = req.getParameter("title");String content = req.getParameter("content");// 3.构造一个blog对象Blog blog = new Blog();blog.setTitle(title);blog.setContent(content);blog.setUserId(user.getUserId());// 4.插入到数据库BlogDao blogDao = new BlogDao();blogDao.insert(blog);// 5.构造重定向  返回到这个博客的详情页resp.sendRedirect("blog_list.html");}
}

② "blogDelete'删除博客

只有一个doGet方法，实现了博客的删除。没有登录或者不是自己的博客的时候是无法删除的。

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("/blog_delete")
public class ServletBlogDelete extends HttpServlet {@Overrideprotected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {// 1. 先判定用户的登陆状态HttpSession session = req.getSession(false);if (session == null) {resp.setStatus(403);resp.setContentType("text/html; charset=utf8");resp.getWriter().write("您当前未登录, 不能删除!");return;}User user = (User) session.getAttribute("user");if (user == null) {resp.setStatus(403);resp.setContentType("text/html; charset=utf8");resp.getWriter().write("您当前未登录, 不能删除!");return;}// 2. 获取到 blogIdString blogId = req.getParameter("blogId");if (blogId == null) {// 这个 blogId 参数不存在, 无法删除resp.setStatus(404);resp.setContentType("text/html; charset=utf8");resp.getWriter().write("您当前删除的 blogId 有误");return;}// 3. 查询出这个 blogId 对应的 Blog 对象BlogDao blogDao = new BlogDao();Blog blog = blogDao.selectOneByBlogId(Integer.parseInt(blogId));if (blog == null) {// 这个 blogId 参数不存在, 无法删除resp.setStatus(404);resp.setContentType("text/html; charset=utf8");resp.getWriter().write("您当前删除的 博客 不存在! blogId=" + blogId);return;}// 4. 判定登陆用户是否就是文章作者if (!blog.getUserId().equals(user.getUserId())) {// blog.getUserId() 文章的作者// user.getUserId() 从 session 里拿的登陆的用户是谁.// 不一样, 说明在删别人的文章.// 直接返回 403System.out.println(user.getUserId());resp.setStatus(403);resp.setContentType("text/html; charset=utf8");resp.getWriter().write("当前您不能删除别人的博客!");return;}// 5. 真正执行删除操作.blogDao.deleteOneByBlogId(Integer.parseInt(blogId));// 6. 返回 302 重定向resp.sendRedirect("blog_list.html");}
}

③ "login"登录状态/注册

doGet：主要是获取登录状态，对应前端getLoginStatus方法
doPost：对应前端login页面，实现用户登录逻辑

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.awt.dnd.MouseDragGestureRecognizer;
import java.io.IOException;@WebServlet("/login")
public class ServletLogin extends HttpServlet {@Overrideprotected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {// 1. 从请求中获取到用户名和密码req.setCharacterEncoding("utf-8");String userId = req.getParameter("userid");String passWord = req.getParameter("password");if (userId == null || userId.equals("") || passWord == null || passWord.equals("")) {// 用户名密码为空. 直接返回登陆失败resp.setContentType("text/html; charset=utf8");resp.getWriter().write("用户名或密码为空! 登陆失败!");return;}// 2. 查询数据库, 验证用户名密码是否正确UserDao userDao = new UserDao();User user = userDao.selectOneByUserId(userId);if (user == null || !user.getPassWord().equals(passWord)) {// 用户名不存在, 或者密码不相同, 返回登陆失败resp.setContentType("text/html; charset=utf8");resp.getWriter().write("用户名或密码错误! 登陆失败!");return;}// 3. 如果正确, 创建一个会话对象HttpSession session = req.getSession(true);// 在会话中保存一下 user, 以备后面使用. 后续访问其他页面, 就可以直接通过会话拿到当前是哪个用户在访问了.session.setAttribute("user", user);// 4. 构造 302 响应报文resp.sendRedirect("blog_list.html");}@Overrideprotected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {// 使用这个方法来针对当前登陆状态进行判定// 1. 获取一下当前的会话.HttpSession session = req.getSession(false);if (session == null) {// 没有会话, 当前是未登录状态resp.setStatus(403);return;}// 这里的 user 对象是否存在, 还是要判定的.// 是否会出现, session 存在, user 不存在的情况呢? 是的!!// 当下没有这个情况, 后面写到 "退出登陆" (注销), 就会涉及到这个情况User user = (User) session.getAttribute("user");if (user == null) {// 虽然有会话, 但是里面没有 user 对象, 也认为是未登录状态resp.setStatus(403);return;}// 2. 返回 200 这样的响应即可//    不写这个代码也行. 默认状态码就是 200resp.setStatus(200);}
}

④ "logout"注销退出账号

doGet：实现了用户登录注销功能，主要就是删除浏览器的session，然后返回登录页面

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 ServletLogout extends HttpServlet {@Overrideprotected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {HttpSession session = req.getSession(false);if (session == null) {resp.setStatus(403);return;}// 直接把 session 中之前的 user 对象给删掉即可!!session.removeAttribute("user");// 不要忘记重定向到登陆页面!resp.sendRedirect("login.html");}
}

⑤ "userInfo"获取登录信息

doGet：在博客列表页 和 博客详情页，的左侧会有用户信息的展示，而获取用户信息就是通过get方法请求"userInfo"来实现的

import com.fasterxml.jackson.databind.ObjectMapper;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("/userInfo")
public class ServletUserInfo extends HttpServlet {private ObjectMapper objectMapper = new ObjectMapper();@Overrideprotected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {// 获取用户信息String blogId = req.getParameter("blogId");if (blogId == null) {// 列表页, 获取当前登陆用户的信息// 直接从 session 中获取即可~~getUserInfoFromSession(req, resp);} else {// 详情页, 获取文章作者的信息// 查询数据库getUserInfoFromDB(req, resp, Integer.parseInt(blogId));}}private void getUserInfoFromDB(HttpServletRequest req, HttpServletResponse resp, int blogId) throws IOException {// 1. 先根据 blogId 查询 Blog 对象, 获取到 userId (作者是谁)BlogDao blogDao = new BlogDao();Blog blog = blogDao.selectOneByBlogId(blogId);if (blog == null) {// 如果参数传来的这个 blogId 是随便瞎写的. 数据库里没有.resp.setStatus(404);resp.setContentType("text/html;charset=utf8");resp.getWriter().write("blogId 不存在");return;}// 2. 根据 userId 查询对应的 User 对象即可UserDao userDao = new UserDao();User user = userDao.selectOneByUserId(blog.getUserId());if (user == null) {resp.setStatus(404);resp.setContentType("text/html;charset=utf8");resp.getWriter().write("blogId 不存在");return;}// 3. 把 user 对象返回给浏览器了user.setPassWord("");resp.setContentType("application/json;charset=utf8");resp.getWriter().write(objectMapper.writeValueAsString(user));}private void getUserInfoFromSession(HttpServletRequest req, HttpServletResponse resp) throws IOException {HttpSession session = req.getSession(false);if (session == null) {resp.setStatus(403);resp.setContentType("text/html;charset=utf8");resp.getWriter().write("当前未登录");return;}User user = (User) session.getAttribute("user");if (user == null) {resp.setStatus(403);resp.setContentType("text/html;charset=utf8");resp.getWriter().write("当前未登录");return;}// user 获取到了, 把 user 中的 password 给干掉, 然后返回.user.setPassWord("");resp.setContentType("application/json; charset=utf8");resp.getWriter().write(objectMapper.writeValueAsString(user));}
}

⑥ "userRegister"注册

实现用户的注册功能,通过接受发来的信息，然后再修改数据库内容即可

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;@WebServlet("/register")
public class ServletUserRegister extends HttpServlet {@Overrideprotected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {req.setCharacterEncoding("utf8");resp.setContentType("text/html;charset=utf8");// 1.获取请求的参数String userId = req.getParameter("username");String passWord = req.getParameter("password");String userName = req.getParameter("name");// 3.构造一个User对象User user = new User();user.setUserId(userId);user.setUserName(userName);user.setPassWord(passWord);// 4.插入到数据库UserDao userDao = new UserDao();userDao.insert(user);// 5.构造重定向  返回到这个博客的详情页resp.sendRedirect("login.html");}
}

⑦ "userUpdate"头像更新

实现了用户头像的上传和数据库内容更新

import javax.servlet.ServletException;
import javax.servlet.annotation.MultipartConfig;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.*;
import java.io.File;
import java.io.IOException;
@MultipartConfig
@WebServlet("/userUpdate")
public class ServletUserUpdate extends HttpServlet {@Overrideprotected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {req.setCharacterEncoding("utf8");resp.setContentType("text/html;charset=utf8");// 1.上传文件Part part = req.getPart("file");//获取HTTP头信息headerInfo=（form-data; name="file" filename="文件名"）String headerInfo = part.getHeader("content-disposition");//从HTTP头信息中获取文件名fileName=（文件名）String fileName = headerInfo.substring(headerInfo.lastIndexOf("=") + 2, headerInfo.length() - 1);//获得存储上传文件的文件夹路径String fileSavingFolder = this.getServletContext().getRealPath("/head");//获得存储上传文件的完整路径（文件夹路径+文件名）//文件夹位置固定，文件夹采用与上传文件的原始名字相同String fileSavingPath = fileSavingFolder + File.separator + fileName;//如果存储上传文件的文件夹不存在，则创建文件夹File f = new File(fileSavingFolder + File.separator);if(!f.exists()){f.mkdirs();}//将上传的文件内容写入服务器文件中part.write(fileSavingPath);//2.修改用户信息HttpSession session = req.getSession(false);if (session == null) {// 没有会话, 当前是未登录状态System.out.println("session为空");resp.setStatus(403);return;}User user = (User) session.getAttribute("user");user.setHead("./head/"+fileName);//3.修改数据库内容UserDao userDao = new UserDao();userDao.update(user);//4.完成后，重定位到博客列表页resp.sendRedirect("blog_list.html");System.out.println("上传文件成功");}
}

（三）其他

文件说明：