Java使用bytearray列表创建nativequery

Question

Hi i am trying to pass list of byteArray to a SQL query but my code doesn't work.

public List<Message> findAll(List<byte[]> ids) {
    String sqlString = "SELECT * FROM MYTABLE WHERE ID in (" + StringUtils.join(ids, ',') + ")";    
    Query query = em.createNativeQuery(sqlString).setParameter(1, ids); 
    return query.getResultList();
}

Answer 1

Your ids is a list of byte arrays (ie, it has two dimensions). The StringUtils.join method doesn't work with that. Plus you don't need to set arrays as a parameter as you haven't specified any parameters in your query.

If you output your SQL string you will see that it is not at all correct.

You will have to flatten out your list of arrays first before using it. Someone can probably do this with streams in one line of code, but an easier way is to use a for loop and a new array.

I haven't tested this, but something like:

List<Strings> list = new ArrayList<>();
for (byte[] idArray : ids) {
    list.add(StringUtils.join(idArray, ','); // join each array
}
String all = StringUtils.join(list, ','); // join all of the arrays