Spring jdbc 两方法分析

1.

List<User> rsList = jdbcTemplate.queryForList(sql,User.class, username);

2

List<User> userList = jdbcTemplate.query(sql, new Object[]{username}, new BeanPropertyRowMapper<User>(User.class));

方法一: error:
org.springframework.jdbc.IncorrectResultSetColumnCountException: Incorrect column count: expected 1, actual 3

原因:

jdbcTemplate.queryForObject(sql, requiredType) 中的requiredType应该为基础类型，和String类型。

public <T> List<T> queryForList(String sql,
                                Class<T> elementType,
                                Object... args)
                         throws DataAccessException
Description copied from interface: JdbcOperations
Query given SQL to create a prepared statement from SQL and a list of arguments to bind to the query, expecting a result list.
The results will be mapped to a List (one entry for each row) of result objects, each of them matching the specified element type.

Specified by:
queryForList in interface JdbcOperations
Parameters:
sql - SQL query to execute
elementType - the required type of element in the result list (for example, Integer.class)
args - arguments to bind to the query (leaving it to the PreparedStatement to guess the corresponding SQL type); may also contain SqlParameterValue objects which indicate not only the argument value but also the SQL type and optionally the scale
Returns:
a List of objects that match the specified element type
Throws:
DataAccessException - if the query fails