How to use PostgreSQL hstore/json with JdbcTemplate

Even easier than JdbcTemplate, you can use the Hibernate Types open-source project to persist HStore properties.

First, you need the Maven dependency:

<dependency>
    <groupId>com.vladmihalcea</groupId>
    <artifactId>hibernate-types-52</artifactId>
    <version>${hibernate-types.version}</version>
</dependency>

Then, assuming you have the following Book entity:

@Entity(name = "Book")
@Table(name = "book")
@TypeDef(name = "hstore", typeClass = PostgreSQLHStoreType.class)
public static class Book {
 
    @Id
    @GeneratedValue
    private Long id;
 
    @NaturalId
    @Column(length = 15)
    private String isbn;
 
    @Type(type = "hstore")
    @Column(columnDefinition = "hstore")
    private Map<String, String> properties = new HashMap<>();
 
    //Getters and setters omitted for brevity
}

Notice that we annotated the properties entity attribute with the @Type annotation and we specified the hstore type that was previously defined via @TypeDef to use the PostgreSQLHStoreType custom Hibernate Type.

Now, when storing the following Book entity:

Book book = new Book();
 
book.setIsbn("978-9730228236");
book.getProperties().put("title", "High-Performance Java Persistence");
book.getProperties().put("author", "Vlad Mihalcea");
book.getProperties().put("publisher", "Amazon");
book.getProperties().put("price", "$44.95");
 
entityManager.persist(book);

Hibernate executes the following SQL INSERT statement:

INSERT INTO book (isbn, properties, id)
VALUES (
    '978-9730228236',
    '"author"=>"Vlad Mihalcea",
     "price"=>"$44.95", "publisher"=>"Amazon",
     "title"=>"High-Performance Java Persistence"',
    1
)

And, when we fetch the Book entity, we can see that all properties are fetched properly:

Book book = entityManager
.unwrap(Session.class)
.bySimpleNaturalId(Book.class)
.load("978-9730228236");
 
assertEquals(
    "High-Performance Java Persistence",
    book.getProperties().get("title")
);

assertEquals(
    "Vlad Mihalcea",
    book.getProperties().get("author")
);

While this question was about Spring's JDBC Template, some users might have an option of using jOOQ instead, which has the jooq-postgres-extensions module that implements support for HSTORE and other data types like CIDR, INET, DATERANGE, INT4RANGE, INT8RANGE, TSRANGE, TSTZRANGE, LTREE, and possibly others, in the future. JSON, JSONB, and XML types are supported too, without the above extensions module.

Your queries can then be written as follows:

ctx.insertInto(HSTORE_TEST)
   .columns(HSTORE_TEST.DATA)
   .values(Hstore.valueOf(Map.of("key1", "value1", "key2", "value2")))
   .execute();

ctx.insertInto(JTEST)
   .columns(JTEST.DATA)
   .values(JSONB.valueOf(
        """
        {"k1": 1, "k2": "two"}
        """))
   .execute();

jOOQ will take care of the data type conversion (for HSTORE) and the required casts of bind variables (e.g. ?::hstore) transparently.

Some JSON functions and operators are available out of the box, for everything else, you can use plain SQL templating

Disclaimer: I work for the company behind jOOQ.

Although quite late for an answer (for the insert part), I hope it might be useful someone else:

Take the key/value pairs in a HashMap:

Map<String, String> hstoreMap = new HashMap<>();
hstoreMap.put("key1", "value1");
hstoreMap.put("key2", "value2");

PGobject jsonbObj = new PGobject();
jsonbObj.setType("json");
jsonbObj.setValue("{\"key\" : \"value\"}");

use one of the following way to insert them to PostgreSQL:

1)

jdbcTemplate.update(conn -> {
     PreparedStatement ps = conn.prepareStatement( "INSERT INTO table (hstore_col, jsonb_col) VALUES (?, ?)" );
     ps.setObject( 1, hstoreMap );
     ps.setObject( 2, jsonbObj );
});

2)

jdbcTemplate.update("INSERT INTO table (hstore_col, jsonb_col) VALUES(?,?)", 
new Object[]{ hstoreMap, jsonbObj }, new int[]{Types.OTHER, Types.OTHER});

3) Set hstoreMap/jsonbObj in the POJO (hstoreCol of type Map and jsonbObjCol is of type PGObject)

BeanPropertySqlParameterSource sqlParameterSource = new BeanPropertySqlParameterSource( POJO );
sqlParameterSource.registerSqlType( "hstore_col", Types.OTHER );
sqlParameterSource.registerSqlType( "jsonb_col", Types.OTHER );
namedJdbcTemplate.update( "INSERT INTO table (hstore_col, jsonb_col) VALUES (:hstoreCol, :jsonbObjCol)", sqlParameterSource );

And to get the value:

(Map<String, String>) rs.getObject( "hstore_col" ));
((PGobject) rs.getObject("jsonb_col")).getValue();