Jdbi - how to bind a list parameter in Java?

问题

We have an SQL statement which is executed by Jdbi (org.skife.jdbi.v2). For binding parameters we use Jdbi's bind method:

Handle handle = ...
Query<Map<String, Object>> sqlQuery = handle.createQuery(query);
sqlQuery.bind(...)

However we have a problem with in-lists and currently we are using String.format for this. So our query can look like this:

SELECT DISTINCT
    tableOne.columnOne,
    tableTwo.columnTwo,
    tableTwo.columnThree
FROM tableOne
JOIN tableTwo
    ON tableOne.columnOne = tableTwo.columnOne
WHERE tableTwo.columnTwo = :parameterOne
    AND tableTwo.columnThree IN (%s)

%s is replaced by String.format so we have to generate a proper string in java code. Then after all %s are replaced we are using jdbi's bind method to replace all other parameters (:parameterOne or ?).

Is there a way to replace String.format with jdbi? There is a method bind(String, Object) but it doesn't handle lists/arrays by default. I have found this article which explains how to write our own factory for binding custom objects but it looks like a lot of effort, especially for something that should be already supported.

回答1:

The article you linked also descibes the @BindIn annotation. This provides a general purpose implementiation for lists.

@UseStringTemplate3StatementLocator
public class MyQuery {
  @SqlQuery("select id from foo where name in (<nameList>)")
  List<Integer> getIds(@BindIn("nameList") List<String> nameList);
}

Please note that you'll have to escape all pointy brackets < like this \\<. There is a previous discusion on SO: How to do in-query in jDBI?

回答2:

I just wanted to add an example since I recently spent considerable time getting a slightly more complex scenario to work :

Query :

select * from sometable where id <:id and keys in (<keys>)

What worked for me :

@UseStringTemplate3StatementLocator
public interface someDAO { 

    ....
    ....
    // This is the method that uses BindIn
    @Mapper(someClassMapper.class)
    @SqlQuery("select something from sometable where age \\< :age and name in (<names>)")
    List<someclass> someMethod (@Bind("age") long age, @BindIn("names") List<string> names);

    @Mapper(someClassMapper.class)
    @SqlQuery("select something from sometable where id = :id")
    List<someclass> someMethod1 (@Bind("id") long id);
    ...
    ...

}

Note: I did have to also add the below dependency since I am using

@UseStringTemplate3StatementLocator 
<dependency>
    <groupId>org.antlr</groupId>
    <artifactId>stringtemplate</artifactId>
    <version>3.2.1</version>
</dependency>

The main thing to observe in the above example : You only need to escape the less than operator (i.e. < ) and not the <> that surround the collection variable (names).

As you can see I did not use a sql.stg file to write my queries in. Initially I incorrectly assumed that when using @UseStringTemplate3StatementLocator , we have to write the queries in the sql.stg file. However, somehow I never got my sql.stg file to work and I eventually reverted back to writing the query within the DAO class using @SqlQuery.

来源：https://stackoverflow.com/questions/32526233/jdbi-how-to-bind-a-list-parameter-in-java

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java

sql

jdbi