How can I Map PostgreSQL Arrays to Java Arrays with Hibernate?

Mapping PostgreSQL Arrays with Hibernate

Issue Encountered

When attempting to map a numeric array column in PostgreSQL to a numeric array field in Java using Hibernate, an exception may occur.

Solution

To resolve this issue, follow these steps:

1. Add Maven Dependency

In your project's pom.xml file, add the following Hibernate Types Maven dependency:

<code class="xml"><dependency>
    <groupId>com.vladmihalcea</groupId>
    <artifactId>hibernate-types-52</artifactId>
    <version>${hibernate-types.version}</version>
</dependency></code>

2. Configure Hibernate Types

In your Hibernate configuration, enable Hibernate Types by adding the following TypeDefs:

<code class="java">@TypeDefs({
    @TypeDef(
        name = "string-array",
        typeClass = StringArrayType.class
    ),
    @TypeDef(
        name = "int-array",
        typeClass = IntArrayType.class
    )
})</code>

3. Define Hibernate Types (Optional)

If the StringArrayType and IntArrayType classes are not defined, you can include them in a superclass:

<code class="java">@MappedSuperclass
public class BaseEntity {

    @Id
    private Long id;

    @Type(type = "string-array")
    private String[] stringArray;

    @Type(type = "int-array")
    private int[] intArray;

    // Getters and setters omitted for brevity
}</code>

4. Map Your Entity

Example mapping:

<code class="java">@Entity(name = "Event")
@Table(name = "event")
public class Event extends BaseEntity {

    @Type(type = "string-array")
    private String[] sensorNames;

    @Type(type = "int-array")
    private int[] sensorValues;

    // Getters and setters omitted for brevity
}</code>

Example Query

<code class="java">Event event = entityManager.find(Event.class, 1L);

// Accessing the mapped array properties
for (String sensorName : event.getSensorNames()) {
    System.out.println(sensorName);
}

for (int sensorValue : event.getSensorValues()) {
    System.out.println(sensorValue);
}</code>

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