调用spring jdbc接口:
User user = (User) this.jdbcTemplate.queryForObject( "SELECT * FROM USER WHERE ID = 1", User.class);
报错如下:
Exception in thread "main" org.springframework.jdbc.IncorrectResultSetColumnCountException: Incorrect column count: expected 1, actual 4 at org.springframework.jdbc.core.SingleColumnRowMapper.mapRow(SingleColumnRowMapper.java:87) at org.springframework.jdbc.core.RowMapperResultSetExtractor.extractData(RowMapperResultSetExtractor.java:92) at org.springframework.jdbc.core.RowMapperResultSetExtractor.extractData(RowMapperResultSetExtractor.java:1) at org.springframework.jdbc.core.JdbcTemplate$1QueryStatementCallback.doInStatement(JdbcTemplate.java:445) at org.springframework.jdbc.core.JdbcTemplate.execute(JdbcTemplate.java:395) at org.springframework.jdbc.core.JdbcTemplate.query(JdbcTemplate.java:455) at org.springframework.jdbc.core.JdbcTemplate.query(JdbcTemplate.java:463) at org.springframework.jdbc.core.JdbcTemplate.queryForObject(JdbcTemplate.java:471) at org.springframework.jdbc.core.JdbcTemplate.queryForObject(JdbcTemplate.java:476) at com.ylp.dao.UserDao.getById(UserDao.java:45) at com.ylp.dao.Test.main(Test.java:17)
大概意思是:查出的数据有4列,它把jdbc.queryForObject("SELECT * FROM USER WHERE ID = 1", User.class);中的第一列转换成User.class,所以 expected 1, actual 6,预期1列,但查出来的数据有4列
修改:
RowMapper<User> rm = ParameterizedBeanPropertyRowMapper.newInstance(User.class); User user = (User) this.jdbcTemplate.queryForObject( "SELECT * FROM USER WHERE ID = 1", rm);