org.springframework.dao.EmptyResultDataAccessException: Incorrect result size: expected 1, actual 0

org.springframework.dao.IncorrectResultSizeDataAccessException: Incorrect result size: expected 1, actual 0

spring的javadoc上讲getObject(String, Object[], Class) will return NULL if the result of the query is NUL

这里有0行和nullresult的区别

0行: select salary from user where 1 = 2

null result: select max(salary) from user where 1 = 2 返回就是null

0行一定抛出IncorrectResultSizeDataAccessException异常

原因如下

ResultSetMetaData rsmd = rs.getMetaData();

int nrOfColumns = rsmd.getColumnCount();这里返回ResultSet的列数

if (nrOfColumns != 1) {

throw new IncorrectResultSizeDataAccessException(

"Expected single column but found " + nrOfColumns, 1, nrOfColumns);

}

0行,多于1行,就抛异常了

以上内容转载自：

/article/5200173.html

具体解决方法：使用如下方法

List<Program> programList = getJdbcTemplate().query(query_sql,

args, new RowMapper() {

public Object mapRow(ResultSet rs, int num)

throws SQLException {

Program program = new Program();

......

return program;

}

});

if(programList!=null &&programList.size()>0){

program = programList.get(0);

}else {

program = null;

}
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