JSP显示新闻列表
MYSQL数据库创建新闻表,用户登陆时使用SERVLET获取用户名,效验通过后直接跳转新闻列表页面,JSP使用EL显示新闻列表
1.首先创建数据库及用户、新闻表
CREATE DATABASE /*!32312 IF NOT EXISTS*/`NewsDB` /*!40100 DEFAULT CHARACTER SET utf8 */; USE `NewsDB`; /*Table structure for table `news` */ DROP TABLE IF EXISTS `news`; CREATE TABLE `news` ( `id` INT(11) NOT NULL AUTO_INCREMENT, `title` VARCHAR(100) DEFAULT NULL, `conetnt` VARCHAR(1000) DEFAULT NULL, `author` VARCHAR(50) DEFAULT NULL, `addtime` DATETIME DEFAULT NULL, PRIMARY KEY (`id`) ) ENGINE=INNODB AUTO_INCREMENT=2 DEFAULT CHARSET=utf8; /*Data for the table `news` */ INSERT INTO `news`(`id`,`title`,`conetnt`,`author`,`addtime`) VALUES (1,'端午节的来源','端午节,又称端阳节、龙舟节、重午节、龙节、正阳节、天中节等,节期在农历五月初五,是中国民间的传统节日。端午节源自天象崇拜,由上古时代祭龙演变而来。仲夏端午,苍龙七宿飞升至正南中天,是龙飞天的日子,即如《易经·乾卦》第五爻的爻辞曰:“飞龙在天”。端午日龙星既“得中”又“得正”,乃大吉大利之象。端午节的起源涵盖了古老星象文化、人文哲学等方面内容,蕴含着深邃丰厚的文化内涵;在传承发展中杂揉了多种民俗为一体,节俗内容丰富。扒龙舟与食粽是端午节的两大礼俗,这两大礼俗在中国自古传承,至今不辍。','test','2020-06-25 10:19:42'); /*Table structure for table `user` */ DROP TABLE IF EXISTS `user`; CREATE TABLE `user` ( `uid` INT(11) NOT NULL AUTO_INCREMENT, `userName` VARCHAR(30) DEFAULT NULL, `pw` VARCHAR(15) DEFAULT NULL, PRIMARY KEY (`uid`) ) ENGINE=INNODB AUTO_INCREMENT=6 DEFAULT CHARSET=gb2312; /*Data for the table `user` */ INSERT INTO `user`(`uid`,`userName`,`pw`) VALUES (1,'admin','admin');
2.新建web项目,项目名称为:JspNewsList 并添加JAR包依赖:mysql-connector-java-5.0.8-bin.jar jstl.jar standard.jar
最终项目结构为
首先新增分别新增login.jsp页面用户登录,failure.jsp用户显示登录出错信息,ShowNews.jsp用于显示新闻详情,ShowNewsList.jsp用于显示新闻列表
详情代码会可以参照码云仓库代码
3.新增Servlet : NewsController.java 并配置在WEB.XML中
<servlet>
<servlet-name>NewsController</servlet-name>
<servlet-class>servlet.NewsController</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>NewsController</servlet-name>
<url-pattern>/NewsController</url-pattern>
</servlet-mapping>
在NewsController.java 中doGet中重写doPost方法并在doPost方法中获取action参数,根据参数不同分别进行不同请求
关键代码:
protected void toShowNews(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setContentType("text/html;charset=utf-8"); String id = request.getParameter("id"); NewsBean newsBean = new NewsService().getNews(id); request.setAttribute("newsBean",newsBean); request.getRequestDispatcher("ShowNews.jsp").forward(request, response); } protected void toShowNewsList(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setContentType("text/html;charset=utf-8"); List<NewsBean> newsList = new NewsService().query_all_news(); request.setAttribute("newsList",newsList); request.getRequestDispatcher("ShowNewsList.jsp").forward(request, response); }
4.创建service类 NewsService.java,在类中调用DAO中并返回新闻信息
public class NewsService { public List<NewsBean> query_all_news() { NewsDao newsDao = new NewsDao(); return newsDao.query_all_news(); } public NewsBean getNews(String id) { NewsDao newsDao = new NewsDao(); return newsDao.getNews(id); } }
5.新增DBUtils.java 及 NewsDao.java类
在DBUtils.java中添加连接数据库及关闭数据库代码
public static Connection getConnection(){
String dbUserName = "root";
String dbUserPasswd = "123456";
String dbURL = "jdbc:mysql://localhost:3406/NewsDB?serverTimezone=Asia/Shanghai";
Connection conn = null;
try {
Class.forName("com.mysql.jdbc.Driver");
conn = (Connection) DriverManager.getConnection(dbURL,dbUserName,dbUserPasswd);
} catch (ClassNotFoundException | SQLException e) {
e.printStackTrace();
}
return conn;
}
public static void closeConnection(Connection conn) {
if(conn != null){
try {
conn.close();
} catch (SQLException e) {
// TODO: handle exception
e.printStackTrace();
}
}
}
public List<NewsBean> query_all_news() { Connection conn = DBUtils.getConnection(); String sql = "select * from news"; ArrayList<NewsBean> results = new ArrayList<NewsBean>(); try { PreparedStatement ps = (PreparedStatement) conn.prepareStatement(sql); ResultSet rs = ps.executeQuery(); while(rs.next()){ NewsBean temp = new NewsBean(); temp.setId(rs.getString("id")); temp.setTitle(rs.getString("title")); temp.setConetnt(rs.getString("conetnt")); temp.setAuthor(rs.getString("author")); temp.setAddtime(rs.getDate("addtime")); results.add(temp); } rs.close(); ps.close(); } catch (SQLException e) { e.printStackTrace(); }finally { DBUtils.closeConnection(conn); } return results; } public NewsBean getNews(String id) { Connection conn = DBUtils.getConnection(); String sql = "select * from news where id='"+id+"' "; NewsBean result = new NewsBean(); try { PreparedStatement ps = (PreparedStatement) conn.prepareStatement(sql); ResultSet rs = ps.executeQuery(); while(rs.next()){ result.setId(rs.getString("id")); result.setTitle(rs.getString("title")); result.setConetnt(rs.getString("conetnt")); result.setAuthor(rs.getString("author")); result.setAddtime(rs.getDate("addtime")); } rs.close(); ps.close(); } catch (SQLException e) { e.printStackTrace(); }finally { DBUtils.closeConnection(conn); } return result; }
6.前端显示页面
<c:forEach items="${newsList }" var="ctxt"> <tr> <td> ${ctxt.title } </td> <td> ${ctxt.author } </td> <td> ${ctxt.addtime } </td> <td><a href="/JspNewsList/NewsController?action=toShowNews&id=${ctxt.id }">查看详情</a></td> </tr> </c:forEach>
最后全部源码放在 https://gitee.com/lg_ui/JspNewsList.git 请有需要的同学参照