java报错:Incorrect column count: expected 1, actual 11
2022-03-01
1、报错原因
主要是以下俩种原因产生的错误,但是编译不报错
//第一种错误
String sql = "select * from user where id = 200000000001";
User s = this.jdbcTemplate.queryForObject(sql, User.class);
//第二种错误
String sql = "select * from user where id = 200000000001";
List<User> userList = jt.queryForList(sql,User.class);
2、解决办法
//第一种错误解决:jdbcTemplate.queryForObject(sql, requiredType) 中的 requiredType 应该为基础类型,和 String 类型
//在返回单个数据时,jdbcTemplate只能返回String.class 或者 Integer.class
String sql = "select * from user where id = 200000000001";
String str = this.jdbcTemplate.queryForObject(sql, String.class);
//第二种错误
//如果要获取多条数据,使用 list 的话
String sql = "select * from user where id = 200000000001";
List<User> userList = jdbcTemplate.query(sql, new Object[]{ }, new BeanPropertyRowMapper<User>(User.class));
if(null!=userList&&userList.size()>0){
User user = userList.get(0);
}