userbean.java

一个小的门户的实现。

package user;

import java.sql.*;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;

public class UserBean {

	public static UserInfo logon(String username, String password)
			throws InstantiationException, IllegalAccessException,
			ClassNotFoundException {
		Connection con = null;
		Statement stmt = null;
		ResultSet rs = null;
		try {
			con = DatabaseBean.getConnection();
			stmt = con.createStatement();
			// 生成查询用户信息的语句
			String sql = "select * from rnms.userinfo where username = '"
					+ username + "' and password = '" + password + "'";

			// 执行查询语句
			rs = stmt.executeQuery(sql);
			while (rs.next()) {
				// 得到查询的结果
				UserInfo user = new UserInfo();
				user.setUserID(rs.getInt(1));
				user.setUserName(rs.getString(2));
				user.setPassword(rs.getString(3));

				return user;
			}
		} catch (SQLException ex) {
			ex.printStackTrace(System.err);
		} finally {
			// 关闭数据库的连接
			DatabaseBean.close(rs, stmt, con);
		}
		return null;
	}

	public Iterator getAllUser() throws Exception {
		String queryString = "select * from rnms.userinfo";
		return executeQuery(queryString);
	}

	public Iterator executeQuery(String sql) {
		Collection ret = new ArrayList();
		try {
			Connection con = DatabaseBean.getConnection();
			Statement stmt = con.createStatement();
			ResultSet rst = stmt.executeQuery(sql);
			while (rst.next()) {
				UserInfo user = new UserInfo();
				user.setUserID(rst.getInt(1));
				user.setUserName(rst.getString(2));
				user.setPassword(rst.getString(3));
				ret.add(user);
			}
			rst.close();
			stmt.close();
			return ret.iterator();
		} catch (Exception e) {
			e.printStackTrace();
			return null;
		}
	}
	
	public void addUser(UserInfo user)
	{
		String sql="insert into course values('"+user.getUserID()+"','"+user.getUserName()+"','"+user.getPassword()+"')";
		executeSql(sql);
	} 

	public void executeSql(String sql)
	   {
	   	 try
	   	 {
	   		Connection con = DatabaseBean.getConnection();
			Statement stmt = con.createStatement();
	   	    stmt.execute(sql);
	   	    stmt.close();
	   	}
	   	catch(Exception e)
	   	{
	   	}
	   }
	public static void main(String[] args) {
//		try {
//			UserInfo user = UserBean.logon("zhou", "zhou");
//			System.out.println("userid :" + user.getUserID());
//			System.out.println("username :" + user.getUserName());
//			System.out.println("password :" + user.getPassword());
//		} catch (Exception e) {
//			e.printStackTrace();
//		}
		
		
		UserBean userBean = new UserBean();
		try{
			Iterator it = userBean.getAllUser();
			while(it.hasNext())
			{
				UserInfo user = (UserInfo)it.next();
				System.out.println(user.getUserID());
				System.out.println(user.getUserName());
				System.out.println(user.getPassword());
			}
		}catch(Exception e){e.printStackTrace();}
	}

}