jdbcservlet.java

该代码是《JSP应用与开发实例》一书的配套光盘

package com.jspdev.ch7;

import java.sql.*;
import javax.sql.*;
import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
import com.microsoft.jdbc.sqlserver.SQLServerDriver;
import java.sql.*;

public class JDBCServlet extends HttpServlet
{
	/**
	 *连接数据库的属性.
	 */
	String driver;
	String url;
	String password;
	String user;
	
	/**
	 *处理Get请求
	 */
	public  void doGet(HttpServletRequest request,
                      HttpServletResponse response)
        throws IOException, ServletException
    {
    	response.setContentType("text/html;charset=gb2312");
        PrintWriter out = response.getWriter();
        try
        {
        	Connection con=getConnection();
	        Statement stmt=con.createStatement();
	        ResultSet rst=stmt.executeQuery("select * from user_info");
	        while(rst.next())
	        {
	        	out.println(rst.getString("userid"));
	        	out.println("<br>");
	        }
	       rst.close();
	       stmt.close();
	       con.close();    	
	   }
	   catch(SQLException e)
	   {
	   	   e.printStackTrace();
	   }
    }
    
    /**
     *处理Post请求
     */
    public  void doPost(HttpServletRequest request,
                      HttpServletResponse response)throws IOException, ServletException
                      
    {
    	doGet(request,response);
    }
    /**
     *获得初始化参数
     */
    public void init()throws ServletException
    {
    	driver=getInitParameter("DRIVER");
    	password=getInitParameter("PASSWORD");
    	url=getInitParameter("URL");
    	user=getInitParameter("USER");
    }
    
    /**
     *帮助方法，获得到数据库的连接
     */
    private Connection getConnection()
    {
    	Connection con=null;
    	 try
	    {
	    	
	    	Class.forName(driver);
			con = DriverManager.getConnection(url,user,password);
		}
		catch(Exception e)
		{
			e.printStackTrace();
		}
		return con;
	}
}