How to convert io.trino.jdbc.Row to java object

[ceciliazcx]

The data set I work with is nested data. resultSet.getObject(id) will return the data as following (but much more complicated) and data type is io.trino.jdbc.Row.

field1={name=name1}, 
field2=[{id=id1, value=value1}, {id=id2, value=value2}]
}

I tried to read data fromio.trino.jdbc.Row but getFields() does not work. and it seems the only way I can do is toString(). Is there other thing I can try to read from io.trino.jdbc.Row?

[hashhar]

getFields seems to work for me - what issue are you running into when you say "but getFields() does not work"?

The other alternative is to read into a Map by doing getObject(column, Map.class).

[ceciliazcx]

Thanks for your replay. I suppose I did not make my question clear. Sorry about it. let me make more details. here are two senarios:

1. res.getObject(listOfMap) will return trinoArray and I need List<Map<String, String>>. I tried (List<Map<String, String>>) res.getObject(columnName, List.class)); but got errors. Is there any other way I can convert it?
2. res.getObject(customObject) will return trinoRow and the actual type is CustomObject. I think I can do trinoRow.getFields().get(1).getValue().get(0).getFields().get(0).getValue().... Then create a new CustomObject and put value. I wonder if there is a better we can handle it? Thanks a lot for your help.

[hashhar]

So you want to map rows into objects - this is generally not something the JDBC driver is responsible for. You'll either need to create a function that takes a ResultSet as input and outputs a custom object created using that result set.
You can use libraries like Jdbi or some ORM to help with the mapping part.

Regarding 1 - here's some code in the form of test code which shows how JDBC and arrays work - this is true for all JDBC drivers - not something specific to Trino.

ResultSet rs = statement.query("VALUES ARRAY[map_from_entries(ARRAY[('k1', 42), ('k2', null)]), map_from_entries(ARRAY[('l1', 42), ('l2', null)])];");

// Java representation of what we expect to get back
Map<String, Integer> expectedElementOne = new HashMap<>();
expectedElementOne.put("k1", 42);
expectedElementOne.put("k2", null);

Map<String, Integer> expectedElementTwo = new HashMap<>();
expectedElementTwo.put("l1", 42);
expectedElementTwo.put("l2", null);

// Let's read using JDBC
// Option 1
Array array = rs.getArray(1);
assertThat(array.getArray()).isEqualTo(new Object[] {expectedElementOne, expectedElementTwo});

// Option 2
array = (Array) rs.getObject(1);
assertThat(array.getArray()).isEqualTo(new Object[] {expectedElementOne, expectedElementTwo});

// Option 3
assertEquals(rs.getObject(1, List.class), List.of(expectedElementOne, expectedElementTwo));