这是一个方便使用jdbc的工具类，使用的时候只需要把这个包导入你要调用sql语句的地方，然后根据需求来选择调用哪一个方法，然后根据返回值选择用什么接收。

package com.utils;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import javax.sql.rowset.CachedRowSet;
import javax.sql.rowset.RowSetProvider;
import com.mchange.v2.c3p0.ComboPooledDataSource;

public class BaseDao {
	private static final ComboPooledDataSource dataSource = new ComboPooledDataSource();
	/**
	 * 封装连接
	 */
	public Connection getConnection() throws SQLException {
		Connection connection = dataSource.getConnection();
		return connection;
	}
	/**
	 * 发送insert delete update 的sql命令 获取执行结果
	 * update student set stuname = ? where stuid = ?
	 * delete from student where stuid = ?
	 */
	public int executeUpdate(String sql,Object ...args) {
		Connection connection = null;
		PreparedStatement  preparedStatement = null;
		try {
			connection = getConnection();
			preparedStatement = connection.prepareStatement(sql);
			if(args!=null) {
				for(int i=0;i<args.length;i++) {
					preparedStatement.setObject(i+1, args[i]);
				}
			}
			int rows = preparedStatement.executeUpdate();
			return rows;
		} catch (SQLException e) {
			e.printStackTrace();
			throw new RuntimeException(e);
		}finally {
			try {
				if(preparedStatement!=null) {
					preparedStatement.close();
				}
				if(connection!=null) {
					connection.close();
				}
			} catch (SQLException e) {
				e.printStackTrace();
				throw new RuntimeException(e);
			}
		}
	}
	/**
	 * 执行select sql 命令的方法
	 */
	public ResultSet executeQuery(String sql,Object ...args) {
		Connection connection = null;
		PreparedStatement preparedStatement = null;
		ResultSet resultSet = null;
		try {
			connection = getConnection();
			preparedStatement = connection.prepareStatement(sql);
			if(args!=null) {
				for(int i=0;i<args.length;i++) {
					preparedStatement.setObject(i+1, args[i]);
				}
			}
			resultSet = preparedStatement.executeQuery();
			CachedRowSet cachedRowSet=RowSetProvider.newFactory().createCachedRowSet();
			cachedRowSet.populate(resultSet);
			return cachedRowSet;
		} catch (SQLException e) {
			e.printStackTrace();
			throw new RuntimeException(e);
		}finally {
			try {
				if(resultSet!=null) {
					   resultSet.close();
				   }
				   if(preparedStatement!=null) {
					   preparedStatement.close();
				   }
				   if(connection!=null) {
					   connection.close();
				   }
			} catch (SQLException e) {
				e.printStackTrace();
				throw new RuntimeException(e);
			}
		}
	}
}