userdao.java

管理系统有一个包

package com.ysl.dao;

import java.sql.PreparedStatement;
import java.util.ArrayList;
import java.util.List;

import com.mysql.jdbc.Connection;
import com.mysql.jdbc.ResultSet;
import com.ysl.model.User;
public class UserDao {
   public boolean addUser(User user)
   {
	   Connection con=null;
	   PreparedStatement ps=null;
	   try{
	      con=ConnectDB.connect();
	      String sql="insert into users(username,userpwd) values(?,?)";
	      ps=con.prepareStatement(sql);
	      ps.setString(1, user.getUsername());
	      ps.setString(2, user.getUserpwd());
	      int n=ps.executeUpdate();
	      return (n>0);
	   }catch(Exception e)
	   {
		   e.printStackTrace();
	   }
	   finally
	   {
		   try{
		     ps.close();
		     con.close();
		   }catch(Exception ee){}
	   }
	   return false;
   }
   public boolean editUser(User user)
   {
	   Connection con=null;
	   PreparedStatement ps=null;
	   try{
	      con=ConnectDB.connect();
	      String sql="update users set username=?,userpwd=? where userid=?";
	      ps=con.prepareStatement(sql);
	      ps.setString(1, user.getUsername());
	      ps.setString(2, user.getUserpwd());
	      ps.setInt(3, Integer.parseInt(user.getUserid()));
	      int n=ps.executeUpdate();
	      return (n>0);
	   }catch(Exception e)
	   {
		   e.printStackTrace();
	   }
	   finally
	   {
		   try{
		     ps.close();
		     con.close();
		   }catch(Exception ee){}
	   }
	   return false;
   }
   public boolean deleteUser(String userid)
   {
	   Connection con=null;
	   PreparedStatement ps=null;
	   try{
	      con=ConnectDB.connect();
	      String sql="delete from users where userid=?";
	      ps=con.prepareStatement(sql);
	      ps.setInt(1, Integer.parseInt(userid));
	      int n=ps.executeUpdate();
	      return (n>0);
	   }catch(Exception e)
	   {
		   e.printStackTrace();
	   }
	   finally
	   {
		   try{
		     ps.close();
		     con.close();
		   }catch(Exception ee){}
	   }
	   return false;
   }
   public User getUser(String userid)
   {
	   Connection con=null;
	   PreparedStatement ps=null;
	   ResultSet rs=null;
	   User user=null;
	   try{
	      con=ConnectDB.connect();
	      String sql="select * from users where userid=?";
	      ps=con.prepareStatement(sql);
	      ps.setInt(1, Integer.parseInt(userid));
	      rs=(ResultSet) ps.executeQuery();
	      if(rs.next())
	      {
	    	  user=new User();
	    	  user.setUserid(rs.getString("userid"));
	    	  user.setUsername(rs.getString("username"));
	    	  user.setUserpwd(rs.getString("userpwd"));
	    	  user.setUserrole(rs.getString("userrole"));
	      }
	      
	   }catch(Exception e)
	   {
		   e.printStackTrace();
	   }
	   finally
	   {
		   try{
			 rs.close();
		     ps.close();
		     con.close();
		   }catch(Exception ee){}
	   }
	   return user;  
   }
   public List getUsers(String username)
   {

	   Connection con=null;
	   PreparedStatement ps=null;
	   ResultSet rs=null;
	   List list=new ArrayList();
	   try{
	      con=ConnectDB.connect();
	      String sql="select * from users where username like ?";
	      ps=con.prepareStatement(sql);
	      ps.setString(1, "%"+username+"%");
	      rs=(ResultSet) ps.executeQuery();
	      while(rs.next())
	      {
	    	  User user=new User();
	    	  user.setUserid(rs.getString("userid"));
	    	  user.setUsername(rs.getString("username"));
	    	  user.setUserpwd(rs.getString("userpwd"));
	    	  user.setUserrole(rs.getString("userrole"));
	    	  list.add(user);
	      }
	      
	   }catch(Exception e)
	   {
		   e.printStackTrace();
	   }
	   finally
	   {
		   try{
			 rs.close();
		     ps.close();
		     con.close();
		   }catch(Exception ee){}
	   }
	   return list;  
   }
   public User checkUser(String username,String userpwd)
   {
	   Connection con=null;
	   PreparedStatement ps=null;
	   ResultSet rs=null;
	   User user=null;
	   try{
	      con=ConnectDB.connect();
	      String sql="select * from users where username=? and userpwd=?";
	      ps=con.prepareStatement(sql);
	      ps.setString(1, username);
	      ps.setString(2, userpwd);
	      
	      rs=(ResultSet) ps.executeQuery();
	      if(rs.next())
	      {
	    	  user=new User();
	    	  user.setUserid(rs.getString("userid"));
	    	  user.setUsername(rs.getString("username"));
	    	  user.setUserpwd(rs.getString("userpwd"));
	    	  user.setUserrole(rs.getString("userrole"));
	      }
	      
	   }catch(Exception e)
	   {
		   e.printStackTrace();
	   }
	   finally
	   {
		   try{
			 rs.close();
		     ps.close();
		     con.close();
		   }catch(Exception ee){}
	   }
	   return user;  
   }
}