How to use PostgreSQL hstore/json with JdbcTemplate

问题

Is there a way to use PostgreSQL json/hstore with JdbcTemplate? esp query support.

for eg:

hstore:

INSERT INTO hstore_test (data) VALUES ('"key1"=>"value1", "key2"=>"value2", "key3"=>"value3"')

SELECT data -> 'key4' FROM hstore_test
SELECT item_id, (each(data)).* FROM hstore_test WHERE item_id = 2

for Json

insert into jtest (data) values ('{"k1": 1, "k2": "two"}');
select * from jtest where data ->> 'k2' = 'two';

回答1:

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:

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

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();

回答2:

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")
);

For more details, check out this article.

来源：https://stackoverflow.com/questions/21383457/how-to-use-postgresql-hstore-json-with-jdbctemplate

标签

java

Spring

postgresql

jdbctemplate

hstore