userDAO類的方法

	public?static?List<User>?getAlluser()?throws?SQLException{

		User?user=new?User();
		List<User>?users=new?ArrayList<User>();
		Connection?connection=DriverManager.getConnection();
		PreparedStatement?pst=null;
		String?sqlString="select?id,name,sex,age?from?student?";
		
			pst=connection.prepareStatement(sqlString);
			ResultSet?rs=pst.executeQuery();
			while?(rs!=null)?{
				user.setId(rs.getInt("id"));
				user.setName(rs.getString("name"));
				user.setSex(rs.getString("sex"));
				user.setAge(rs.getInt("age"));
				users.add(user);
				
			}			
		return?users;
	}
	
	

測試類：

import?java.sql.SQLException;
import?java.util.ArrayList;
import?java.util.List;

import?cn.qy.com.DAO.userDAO;
import?cn.qy.com.common.User;


public?class?dbTest?{

	public?static?void?main(String[]?args)??{
		
		userDAO?userDao=new?userDAO();
	
		try?{
			List<User>?users?=?userDao.getAlluser();
			System.out.println("-------所有的用戶信息如下------------");
		????for?(User?u:users)?{
				System.out.println("編號："+u.getId()+"????姓名："+u.getName()+
						"???性別："+u.getSex()+"??年齡："+u.getAge()+"<br>");
			}
		}?catch?(SQLException?e)?{
			e.printStackTrace();
		}
	????
	}

}

出現(xiàn)的異常是：

java.sql.SQLException:?Before?start?of?result?set
	at?com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1078)
	at?com.mysql.jdbc.SQLError.createSQLException(SQLError.java:989)
	at?com.mysql.jdbc.SQLError.createSQLException(SQLError.java:975)
	at?com.mysql.jdbc.SQLError.createSQLException(SQLError.java:920)
	at?com.mysql.jdbc.ResultSetImpl.checkRowPos(ResultSetImpl.java:855)
	at?com.mysql.jdbc.ResultSetImpl.getInt(ResultSetImpl.java:2710)
	at?com.mysql.jdbc.ResultSetImpl.getInt(ResultSetImpl.java:2851)
	at?cn.qy.com.DAO.userDAO.getAlluser(userDAO.java:74)
	at?dbTest.main(dbTest.java:38)