userdao.java

毕业设计JSP公交车查询系统

package bus.dao;

import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

import bus.bean.UserBean;
import bus.db.Conn;

public class UserDao {

	private	Conn c=new Conn();
//	private Connection connection;
	private PreparedStatement prepar;
	private ResultSet res;

	public UserBean checkLogin(String username,String password)
	{
		UserBean ub = null;
	  
	    try
	    {
	        String sql="select count(*) from users where username=? and password=?";
	        
	        prepar = c.getPre(sql);
	        prepar.setString(1, username);
	        prepar.setString(2, password);
	       
	        res = prepar.executeQuery();
	       
	        if (res.next())
	        {
	       	if (res.getInt(1) > 0)
	           {
	               ub = this.getUser(username);
	           }
	           else
	           {
	               ub = null;
	           }
	       }
	        
	    }
	    catch (Exception e)
	    {
	        ub = null;
	        e.printStackTrace();
	    }
	    return ub;
	}
	   
	    public UserBean getUser(String username) //提取登陆用户信息
	    {
	        UserBean ub = new UserBean();
	        String sql = "select * from users where username=?";
	        try
	        {
	        	prepar = c.getPre(sql);
	            prepar.setString(1, username);
	            res = prepar.executeQuery();
	            while (res.next())
	            {
	            	ub.setId(res.getInt("id"));
	                ub.setUsername(res.getString("username"));
	                ub.setPassword(res.getString("password"));
	               
	                
	            }
	        }
	        catch (SQLException ex)
	        {
	            ex.printStackTrace();
	        }

	        return ub;
	    }

	   
	    public boolean addUserBean(UserBean ub)
	    {
	        boolean flag = false;
	        String sql = "insert into users (username,password) values(?,?)";
	      
	        if (hasUser(ub.getUsername()))
	        {
	            return false;
	        }
	        try
	        {
	            prepar = prepar = c.getPre(sql);
	            prepar.setString(1, ub.getUsername());
	            prepar.setString(2, ub.getPassword());
	           
	            
	           
	          
	            
	           
	            int result = prepar.executeUpdate();
	            if (result > 0)
	            {
	                flag = true;
	            }
	            else
	            {
	                flag = false;
	            }

	        }
	        catch (Exception ex)
	        {
	            flag = false;
	            ex.printStackTrace();
	        }

	        return flag;
	    }

	    public boolean hasUser(String username)
	    {
	        boolean flag = true;
	        String sql = "select count(*) from users where username=?";
	        try
	        {
	            prepar  = c.getPre(sql);
	            prepar.setString(1, username);
	            res = prepar.executeQuery();
	            res.next();
	            int result = res.getInt(1);
	            if (result > 0)
	            {
	                flag = true;
	            }
	            else
	            {
	                flag = false;
	            }
	        }
	        catch (SQLException ex)
	        {
	            ex.printStackTrace();
	            flag = true;
	        }

	        return flag;
	    }
	    
	    public ResultSet getResultSet(String sql)
	    {
	    	return c.executeQuery(sql);
	    }
	    
	    public boolean updateUser(UserBean ub)
	    {
	    	boolean flag = false;
	        String sql = "update users set  password=? where id=?";
	        try
	        {
	            
	            prepar  = c.getPre(sql);
	           
	            prepar.setString(1, ub.getPassword());
	           
	            prepar.setInt(2, ub.getId());
	            int result = prepar.executeUpdate();
	            if (result > 0)
	            {
	                flag = true;
	            }
	            else
	            {
	                flag = false;
	            }
	        }
	        catch (Exception ex)
	        {
	            flag = false;
	            ex.printStackTrace();
	        }
	        return flag;
	    }
	    
	    public boolean deletUser(int id)
	    {
	    	boolean flag = false;
	        String sql = "delete from users where id=?";
	        try
	        {
	           
	            prepar  = c.getPre(sql);
	           
	            prepar.setInt(1, id);
	            int result = prepar.executeUpdate();
	            if (result > 0)
	            {
	                flag = true;
	            }
	            else
	            {
	                flag = false;
	            }
	        }
	        catch (Exception ex)
	        {
	            flag = false;
	            ex.printStackTrace();
	        }
	        return flag;
	    	
	    }
	   
	    public boolean getZhanDian(String name,int id)
	    {
	    	
	    	boolean flag = true;
	        String sql = "select count(*) from zhandian where line_id=? and content=?";
	        try
	        {
	            prepar  = c.getPre(sql);
	            prepar.setInt(1,id);
	            prepar.setString(2, name);
	            res = prepar.executeQuery();
	            res.next();
	            int result = res.getInt(1);
	            if (result > 0)
	            {
	                flag = true;
	            }
	            else
	            {
	                flag = false;
	            }
	        }
	        catch (SQLException ex)
	        {
	            ex.printStackTrace();
	            flag = true;
	        }

	        return flag;
	    	
	    }
	    
}