标签:exe sele png jstl dbutils return 依赖 ext 连接数
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:
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
标签:exe sele png jstl dbutils return 依赖 ext 连接数
原文地址:https://www.cnblogs.com/beginner1/p/13191363.html