connecttag.java

JSP学习的好东东

import javax.servlet.jsp.*;
import javax.servlet.jsp.tagext.*;
import java.io.*;
import java.sql.*;

public class ConnectTag extends TagSupport
{
	public static final String DRIVER_CLASS = "sun.jdbc.odbc.JdbcOdbcDriver";
	private String url;
	
	public void setUrl(String url)
	{
		this.url = url.trim();
		System.out.println("ConnectTag.setUrl()......");
	}
	
	private Connection con;
	private Statement stmt;
	private ResultSet rs;
	
	public Connection getConnection() { return con; }
	public Statement getStatement() { return stmt; }
	public ResultSet getResultSet() { return rs; }
	
	public void runQuery(String sql) throws SQLException
	{
		rs = stmt.executeQuery(sql);
		System.out.println("ConnectTag.runQuery()......");
	}
	
	public int doStartTag() throws JspException
	{
		con = null;
		try{
			Class.forName(DRIVER_CLASS);
			con = DriverManager.getConnection("jdbc:odbc:" + url, "sa", "");
			stmt = con.createStatement();
		}catch(Exception e){
			System.out.println("Error in ConnectTag::doStartTag()");
			throw new JspException(e.getMessage());
			
		}
		System.out.println("ConnectTag.doStartTag()......");
		return EVAL_BODY_INCLUDE;
	}

	public int doEndTag() throws JspException
	{
		try{
			if(rs != null){
				rs.close();
				rs = null;
			}
			if(stmt != null){
				stmt.close();
				stmt = null;
			}
			if(con != null){
				con.close();
				con = null;
			}
		}catch(SQLException e){
			throw new JspException(e.getMessage());
		}
		System.out.println("ConnectTag.doEndTag()......");
		
		System.out.println("EVAL_PAGE=" + TagSupport.EVAL_PAGE);
		System.out.println("SKIP_PAGE=" + TagSupport.SKIP_PAGE);
		System.out.println("SKIP_BODY=" + TagSupport.SKIP_BODY);
		System.out.println("EVAL_BODY_INCLUDE=" + TagSupport.EVAL_BODY_INCLUDE);
		System.out.println("EVAL_BODY_TAG=" + BodyTagSupport.EVAL_BODY_TAG);
		return EVAL_PAGE;
	}
	
}