dbconn.java

实现叫简单但是很经典的新闻发布管理系统

package news;
import java.sql.*;
import javax.naming.*;
import javax.sql.DataSource;
public class DBConn{
  private Connection conn;
  public DBConn()
   {
     try{
  	 
     //加载驱动程序
     Context initCtx = new InitialContext();
     Context ctx = (Context) initCtx.lookup("java:comp/env");
     //获取连接池对象
     DataSource ds =(DataSource)ctx.lookup("jdbc/news");
     //创建连接
     conn = ds.getConnection();
     /*
    	 Class.forName("oracle.jdbc.driver.OracleDriver");
    	 String url="jdbc:oracle:thin:@localhost:1521:zwg";
    	 conn = DriverManager.getConnection(url, "mydatabase", "zwg");
    	 conn.setAutoCommit(false);
    	 */
    	 
    }
    catch(Exception e)
    {
      System.out.print(e.toString());
    }
  }
  public synchronized Statement getStmt()throws Exception
   {
     Statement stmt;
     stmt=conn.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,ResultSet.CONCUR_READ_ONLY);
     return stmt;
   }
  //创建预处理会话对象
  public synchronized PreparedStatement getPstmt(String sql)throws Exception
   {
     PreparedStatement pstmt;
     pstmt=conn.prepareStatement(sql,ResultSet.TYPE_SCROLL_INSENSITIVE,ResultSet.CONCUR_READ_ONLY);
     return pstmt;
   }
  //执行查询操作
  public synchronized ResultSet query(String sql)throws Exception
 {
  try{
    Statement stmt;
    stmt=conn.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,ResultSet.CONCUR_READ_ONLY);
    ResultSet rs=stmt.executeQuery(sql);
    return rs;
   }
  catch(Exception e)
  {
   System.out.println(e.toString());
   return null;
  }
 }
 //执行更新操作
public synchronized int update(String sql)throws Exception
 {
   int nn;
   try{
   Statement stmt;
   stmt=conn.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,ResultSet.CONCUR_READ_ONLY);
   nn=stmt.executeUpdate(sql);
  }
  catch(Exception e)
  {
   System.out.println(e.toString());
   nn=0;
  }
  return nn;
 }
 public void DBclose() throws SQLException {
   if(conn!=null){
     conn.close();
     conn=null;
   }
 }
}