DAO进阶！!
文件名：
NewsDAOMySQL.java
package news;
import java.sql.*;
import java.util.*;
public class NewsDAOMySQL implements NewsDAO
{
Connection conn = null;
Statement stmt = null;
ResultSet rs = null;
News news = null;
String url="jdbc:mysql://localhost:3306/joke?user=root";
public NewsDAOMySQL()
{
try {
Class.forName ("com.mysql.jdbc.Driver");
}
catch (java.lang.ClassNotFoundException e) {
System.err.println("joke():"+e.getMessage());
}
}
public News getNewsByPrimaryKey(int newsid) throws SQLException
{
Connection conn=null;
Statement stmt;
ResultSet rs;
News news = null;
String sql="select newsid,title,content from news2"+
" where newsid="+newsid+"";
conn = getConnection();
stmt = conn.createStatement();
rs=stmt.executeQuery(sql);
if(rs.next())
{
news = new News(rs.getInt(1), rs.getString(2),rs.getString(3));
}
rs.close();
stmt.close();
conn.close();
return news;
}
private Connection getConnection() throws SQLException
{
Connection conn = null;
conn = DriverManager.getConnection(url);
return conn;
}
public News[] getAllNews() throws SQLException
{
String sql="select newsid,title,content from news2";
conn = getConnection();
stmt = conn.createStatement();
rs=stmt.executeQuery(sql);
List list = new ArrayList();
while(rs.next())
{
list.add(new News(rs.getInt(1), rs.getString(2),rs.getString(3)));
}
conn.close();
if(list.size() == 0) return null;
News[] news = new News[list.size()];
return (News[])list.toArray(news);
}
}
文件名：NewsDAO
package news;
import java.sql.SQLException;
public interface NewsDAO {
public News getNewsByPrimaryKey(int newsid) throws SQLException;
public News[] getAllNews() throws SQLException;
}
文件名：
NewsDAOFactory.java
package news;
public class NewsDAOFactory {
public static NewsDAO getDAO() throws Exception {
NewsDAO newsDao = null;
String className = "news.NewsDAOMySQL";
try {
newsDao = (NewsDAO) Class.forName(className).newInstance();
}
catch (Exception se) {
}
return newsDao;
}
}
调用文件名：
getAllNews.jsp
<%@page contentType="text/html;charset=gb2312" %>
<%@page import="news.*" %>
<%
NewsDAO newsDao = NewsDAOFactory.getDAO();
News[] news = newsDao.getAllNews();
if(news != null) {
for(int i=0;i<news.length;i++)
{ out.println("Newsid1:"+news<i>.getNewsid());
out.println("<br>");
out.println("Title:"+news<i>.getTitle());
out.println("<br>");
out.println("Body:"+news<i>.getContent());
}
}
else out.println("Failed.");
%>
lunzi
2004-12-21 21:05:11
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