userdao.java

图书管理系统

/**
 * 用于操作User的类
 */
package fuguo.yy1.dao;

/**
 * @author cankongyun
 *
 */
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;

import fuguo.yy1.util.SQLConstants;
import fuguo.yy1.base.BaseDAO;
import fuguo.yy1.base.BaseDTO;
import fuguo.yy1.db.DBConn;
import fuguo.yy1.dto.User;

public class UserDAO implements BaseDAO{
	
	private static Connection con=DBConn.getConnection();
	private static PreparedStatement pstmt=null;
	private static ResultSet rs=null;
	
	 /**
     * 用户登录验证方法
     * @param _baseDTO
     * @return User
     */
    public static User loginValidate(User _user)
    {
        try
        {
        	pstmt = con.prepareStatement(SQLConstants.SELECT_CHECK_USER);
            pstmt.setString(1, _user.getUserName());
            pstmt.setString(2, _user.getPassWord());
            rs = pstmt.executeQuery();
            while(rs.next()){
            	_user.setId(rs.getInt("id"));
            	_user.setUserName(_user.getUserName());
            	
            	return _user;
            }
            
            DBConn.releaseConnection(rs,pstmt,null);
        }
        catch(SQLException se){
        	System.err.println("用户登陆验证失败！出现异常："+se.getMessage());
        }
        return null;
    }

    /**
     * 检测用户名是否存在方法
     * @param _userName
     * @return boolean
     */
    public static boolean checkUserName(String _userName)
    {
        boolean exist = false;
        try
        {
            pstmt = con.prepareStatement(SQLConstants.SELECT_CHECK_USERNAME);
            pstmt.setString(1, _userName);
            rs = pstmt.executeQuery();
            exist = rs.next();
            DBConn.releaseConnection(rs,pstmt,null);
        }catch(SQLException se){
            System.err.println("检测用户名是否存在失败！出现异常："+se.getMessage());
        }
        return exist;
    }

    /**
     * 添加用户方法
     * @param _user
     * @return int
     */
    public static int insertUser(User _user)  {
        int result = 0;
        try{
            pstmt = con.prepareStatement(SQLConstants.INSERT_USER);
            pstmt.setString(1, _user.getUserName());
            pstmt.setString(2, _user.getPassWord());
            pstmt.setString(3, _user.getGender());
            pstmt.setInt(4,_user.getAge());
            result = pstmt.executeUpdate();

            DBConn.releaseConnection(null,pstmt,null);
       }catch(SQLException se)            {
            System.out.println("用户注册失败！出现异常："+se.getMessage());
       }
        return result;
    }
    
    /**
     * 显示所有用户
     * @return ArrayList
     */
    public static ArrayList users(){
    	ArrayList al=new ArrayList();
    	User user=null;
		try{
			pstmt=con.prepareStatement(SQLConstants.SELECT_USERS);
			rs=pstmt.executeQuery();
			while(rs.next()){
				user=new User();
				user.setId(rs.getInt("id"));
				user.setUserName(rs.getString("userName"));
				user.setPassWord(rs.getString("passWord"));
				user.setGender(rs.getString("gender"));
				user.setAge(rs.getInt("age"));
				//将user对象加入al容器中
				al.add(user);	
			}
			DBConn.releaseConnection(rs,pstmt,null);
		}catch(SQLException se){
			System.err.println("显示所有用户失败!出现异常:"+se.getMessage());
		}    	
    	return al;
    }
    
    
    /**
     * 根据Id查询用户信息方法
     * @param _id
     * @return User
     */
    public static User selectUserById(int _id){
    	
    	User user=null;
    	try{
    		pstmt=con.prepareStatement(SQLConstants.SELECT_USER_ID);
    		pstmt.setInt(1,_id);
    		rs=pstmt.executeQuery();    		
    		
    		while(rs.next()){
    			user=new User();
    			user.setId(rs.getInt("id"));
    			user.setUserName(rs.getString("userName"));
    			user.setPassWord(rs.getString("passWord"));
    			user.setGender(rs.getString("gender"));
    			user.setAge(rs.getInt("age"));
    			
    			return user;
   			
    		}
    		DBConn.releaseConnection(rs,pstmt,null);
    		
    	}catch(SQLException se){
    		System.err.println("根据Id查询用户信息失败！出现异常："+se.getMessage());
    	}
    	
    	return null;
    }
    
    /**
     * 修改用户信息方法
     * @param _id
     * @param _user
     * @return int
     */
    public static int updateUser(int _id, BaseDTO _baseDTO)
    {
        int result = 0;
        User user=(User)_baseDTO;
        try
        {
            pstmt = con.prepareStatement(SQLConstants.UPDATE_USER);
            pstmt.setString(1, user.getGender());
            pstmt.setInt(2, user.getAge());
            pstmt.setInt(3,_id);
            result = pstmt.executeUpdate();
            DBConn.releaseConnection(null,pstmt,null);
        }
        catch(SQLException se){
            System.err.println("修改用户信息失败！出现异常："+se.getMessage());
        }
        return result;
    }
    
    
    /**
     * 删除用户信息的方法
     * @param _id
     * @return int
     */
    public static int deleteUser(int _id){
    	int result=0;
    	try{
    		pstmt=con.prepareStatement(SQLConstants.DELETE_USER);
    		pstmt.setInt(1,_id);
    		result=pstmt.executeUpdate();
    		
    		DBConn.releaseConnection(null,pstmt,null);
    	}catch(SQLException se){
    		
    		System.err.println("删除用户信息失败，出现异常："+se.getMessage());
    	}
    	return result;
    	
    }
	
}