JSP显示新闻

2021-02-05 19:14

阅读：492

标签：username auth upd test forward 修改 pst 菜单 request

JSP显示新闻

1、项目结构

　　java：

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　　Web：

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2、Java部分详细介绍

2.1 Controller

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GetSessionServlet：　
- 显示在线人数的Servlet，具体介绍见上一篇博客https://www.cnblogs.com/luomei/p/13034052.html

LoginServlet：

用来获取网站的登录信息，并传给UsersService进行处理判断

 1 package Controller;
 2 
 3 import Entity.Users;
 4 import Service.UsersService;
 5 import Util.CookieSave;
 6 import javax.servlet.ServletException;
 7 import javax.servlet.annotation.WebServlet;
 8 import javax.servlet.http.HttpServlet;
 9 import javax.servlet.http.HttpServletRequest;
10 import javax.servlet.http.HttpServletResponse;
11 import java.io.IOException;
12 import java.sql.SQLException;
13 
14 @WebServlet(name = "Controller.LoginServlet")
15 public class LoginServlet extends HttpServlet {
16     protected void doPost(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException {
17         doGet(request,response);
18     }
19     protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
20         response.setContentType("text/html;charset=utf-8");
21         request.setCharacterEncoding("utf-8");
22         //Login的处理
23         try {
24             Login(request,response);
25         } catch (SQLException e) {
26             e.printStackTrace();
27         }
28     }
29     void Login(HttpServletRequest request, HttpServletResponse response) throws IOException, SQLException {
30         //获取表单中的数据的值
31         Users user=new Users();
32         user.setName(request.getParameter("username"));
33         user.setPassword(request.getParameter("password"));
34         System.out.println("登入用户名："+user.getName());
35         System.out.println("登入用户密码："+user.getPassword());
36         System.out.println("-------------------------------");
37         //验证用户名密码
38         UsersService usersService=new UsersService();
39         boolean hasUsers=usersService.QueryUsers(user);
40         if(hasUsers){
41             CookieSave cookieSave=new CookieSave();
42             cookieSave.Save(response,"username",user.getName(),60*60*24*30);
43             cookieSave.Save(response,"password",user.getPassword(),60*60*24*30);
44             //成功登录，进入管理主界面
45             response.sendRedirect("yinglang/index.html");
46         }else
47         {
48             response.getWriter().println("登陆失败");
49             //登录失败，返回登陆界面
50             response.sendRedirect("login.html");
51         }
52     }
53 }

ShowNewsListServlet：

从NewsService中获取所需的数据，并将数据传递给ShowNewsList.jsp来显示

package Controller;

import Entity.News;
import Service.NewsService;
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.SQLException;
import java.util.List;

@WebServlet(name = "Controller.ShowNewsListServlet")
public class ShowNewsListServlet extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        doGet(request,response);
    }
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        request.setCharacterEncoding("utf-8");
        NewsService newsService=new NewsService();
        try {
            List lsNews=newsService.QueryNews();
            request.setAttribute("lsNews",lsNews);
            request.getRequestDispatcher("ShowNewsList.jsp").forward(request,response);
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}

2.2 DAL

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SqlHelper

用以连接数据库，这里我选用的是MySql

package DAL;
import com.mysql.jdbc.StatementImpl;
import java.sql.*;

public class SqlHelper {
    public static Connection getConnection() {
        Connection connection = null;
        try {
            Class.forName("com.mysql.jdbc.Driver");
            connection = DriverManager.getConnection("jdbc:mysql://127.0.0.1:3306/servletdata?useSSL=true&characterEncoding=utf-8&user=root&password=");
            System.out.println("数据库连接成功！");
            System.out.println("-------------------------------");
            return connection;
        } catch (Exception e) {
            e.printStackTrace();
        }
        System.out.println("创建连接失败！");
        System.out.println("-------------------------------");
        return null;
    }
    //select
    public static ResultSet executeQuery(String SQL)
    {
        try
        {
            Connection conn=getConnection();
            Statement stmt=conn.createStatement();
            ResultSet rs=stmt.executeQuery(SQL);
            return rs;
        } catch (SQLException e) {
            e.printStackTrace();
            System.out.println("查询失败！");
            System.out.println("-------------------------------");
            return null;
        }
    }
    //insert update delete
    public static boolean executeUpdate(String SQL)
    {
        try
        {
            Connection conn=getConnection();
            Statement stmt=conn.createStatement();
            int rs=stmt.executeUpdate(SQL);
            if (rs>0)
                return true;
            else
                return false;
        } catch (SQLException e) {
            e.printStackTrace();
            System.out.println("更新失败！");
            System.out.println("-------------------------------");
            return false;
        }
    }
    public static void ShutDown(StatementImpl statement, Connection connection) {
        if (statement != null) {
            try {
                statement.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
        if (connection != null) {
            try {
                connection.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }

        }
    }
}

2.3 Entity

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News

用于映射数据库中的news表

package Entity;

import java.sql.Date;

public class News {
    private int idnews;
    private String category;
    private String title;
    private String content;
    private String author;
    private Date newsdate;

    public int getIdnews() {
        return idnews;
    }
    public void setIdnews(int idnews) {
        this.idnews = idnews;
    }
    public String getCategory() {
        return category;
    }
    public void setCategory(String category) {
        this.category = category;
    }
    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 getAuthor() {
        return author;
    }
    public void setAuthor(String author) {
        this.author = author;
    }
    public Date getNewsdate() {
        return newsdate;
    }
    public void setNewsdate(Date newsdate) {
        this.newsdate = newsdate;
    }

}

Users

用于映射数据库中的users表

package Entity;

public class Users {
    String name="";//用户名
    String password="";//用户密码

    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public String getPassword() {
        return password;
    }
    public void setPassword(String password) {
        this.password = password;
    }
}

2.4 Service

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NewsService

提供News类的数据服务（目前只完善了查询所有新闻内容的函数）

package Service;

import DAL.SqlHelper;
import Entity.News;

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

public class NewsService {
    public void AddNews(){}
    public void DeleteNews(){}
    public void UpdateNews(){}
    public List QueryNews() throws SQLException {
        String sql="Select * from news";
        ResultSet rs= SqlHelper.executeQuery(sql);
        List lsNews=new ArrayList();
        while (rs.next())
        {
            News news=new News();
            news.setIdnews(rs.getInt(1));
            news.setCategory(rs.getString(2));
            news.setTitle(rs.getString(3));
            news.setContent(rs.getString(4));
            news.setAuthor(rs.getString(5));
            news.setNewsdate(rs.getDate(6));
            lsNews.add(news);
        }
        return lsNews;
    }
    public void GetNews(){}
}

UsersService

提供Users类的数据服务（目前只完善了验证用户信息是否正确的函数）

package Service;

import DAL.SqlHelper;
import Entity.News;
import Entity.Users;
import com.mysql.jdbc.PreparedStatement;

import java.sql.ResultSet;
import java.sql.SQLException;

public class UsersService {
    public void AddUsers(){}
    public void DeleteUsers(){}
    public void UpdateUsers(){}
    public boolean QueryUsers(Users user) throws SQLException {
        //验证用户名存在性
        PreparedStatement pstmt;
        String sql = "select * from  users where username=‘"+user.getName()+"‘ and password=‘"+user.getPassword()+"‘";
        ResultSet rs= SqlHelper.executeQuery(sql);
        if (rs.next()) {
            return true;
        }
        return false;
    }
    public void GetUsers(){}
}