MySQL PreparedStatement 连接数据库抛 MySQLSyntaxErrorException

简单的用JDBC连接数据库，采用的是PreparedStatement进行数据查询，

连接数据库的时候出现这种问题：

com.mysql.jdbc.exceptions.MySQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '?' at line 1

代码长这样：

String sql = "select * from charge  where user_id = ?";
		Connection connection = ConnUtil.getConnection();
		PreparedStatement statement = null;
		ResultSet resultSet = null;
		List<Charge> charges = null;
		try {
			statement = connection.prepareStatement(sql);
			statement.setInt(1, userId);
			resultSet = statement.executeQuery(sql);

一开始以为是SQL写的有问题，然后尝试将“?”替换成数字，发现是可以的

select * from charge  where user_id = 1

所以就很无语了。在网上查了好久，最后发现将下面语句替换下就可以了：

resultSet = statement.executeQuery(sql);

替换成：

resultSet = statement.executeQuery();

具体为什么还来不及去研究

参考：http://stackoverflow.com/questions/7574134/jdbc-returning-mysqlsyntaxerror-exception-with-correct-statement