dao.java

本光盘包含了本书各章中出现的所有程序的源代码。 1. 如果是Java程序

package dbcp;

import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

public class Dao {
	
	/**
	 * 判断用户是否存在
	 * @param username
	 * @param password
	 * @return
	 */
	public static boolean validate(String username,String password){
		Connection conn=null;
		ResultSet rs=null;
		Statement stmt = null;
		try {
			//取数据库连接
			 conn = DBPool.getConnection();
			 stmt = conn.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,ResultSet.CONCUR_UPDATABLE);			
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		
		String sql="select * from t_user where username='"+username+"' and password='"+password+"'";
		
		
			 try {
				rs = stmt.executeQuery(sql);
			} catch (SQLException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
			
			try {
				return rs.next();
			} catch (SQLException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
			return false;
		
	}//validate 
	
	/**
	 * 注册新用户
	 * @param username
	 * @param password
	 * @return
	 */
	public static boolean addUser(String username,String password){
		Connection conn=null;
		ResultSet rs=null;
		Statement stmt = null;
		try {
			//取数据库连接
			 conn = DBPool.getConnection();
			 stmt = conn.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,ResultSet.CONCUR_UPDATABLE);			
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		
		String sql="insert into t_user (username,password)values('"+username+"','"+password+"')";
		
		
			 try {
				 stmt.execute(sql);
				 return true;
			} catch (SQLException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
			
			
			return false;
		
	}
	
}