Java Hibernate、Postgres 和数组类型

Hibernate, Postgres & Array Type

提问by Damien C

I'm stuck on a specific issue using array typein postgresql 9.3 mapped with hibernate 4.1.0. This type allows me to have really strong data model, without building lots of tables and joins.

我在使用映射到休眠 4.1.0 的 postgresql 9.3 中的数组类型遇到了一个特定问题。这种类型允许我拥有非常强大的数据模型，而无需构建大量表和连接。

In order to map a field stored with this particular type, I have used a UserType

为了映射使用此特定类型存储的字段，我使用了UserType

Anyway, it works well with pure hibernate (hql) but I need also to send sql native queryto my database. When I do it, in spite of many tries, I have not found any way to do that.

无论如何，它适用于纯休眠（hql），但我还需要将sql 本机查询发送到我的数据库。当我这样做时，尽管尝试了很多次，但我还没有找到任何方法来做到这一点。

I try many syntaxes based on this

我尝试了许多基于此的语法

String[] values = {"value1", "value2"};
String queryString = "SELECT * FROM instances WHERE values && :values";
Query query = this.getSession().createSQLQuery(queryString).addEntity(Instance.class);
query.setParameterList("values", values);
query.list();

I got Operator does not exists : text[] && character varying

我得到运算符不存在：text[] && 字符变化

It should give following syntax in jdbc : ['value1', 'value2'] and it seems to give 'value1'...

它应该在 jdbc 中给出以下语法： ['value1', 'value2'] 并且它似乎给出了 'value1'...

I tried many syntaxes with

我尝试了很多语法

• Collection
• Pure Arrays
• [ :values ] syntax : I got Syntax error near "["

• 收藏
• 纯数组
• [ :values ] 语法：我在“[”附近遇到语法错误

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I need to send native query because I use Materialized Viewfor performance gains.

我需要发送本机查询，因为我使用物化视图来提高性能。

My SQL Query works in postgresql console. So it is an hibernate specific issue.

我的 SQL 查询在 postgresql 控制台中工作。所以这是一个休眠特定的问题。

采纳答案by Damien C

I tried few versions based on Array Type introduced by JDBC4 : How can I set a String[] parameter to a native query?. Problem is also Hibernate (even in last version 4.3.1.final) does not work with this new features and gave me following error message

我尝试了几个基于 JDBC4 引入的数组类型的版本：如何将 String[] 参数设置为本机查询？. 问题也是 Hibernate（即使在最新版本 4.3.1.final 中）也不适用于此新功能，并给了我以下错误消息

Could not determine a type for class: org.postgresql.jdbc4.Jdbc4Array

So I had to make a Specific UserType (based on several articles in stackoverflow, and others sources)

所以我必须创建一个特定的 UserType（基于 stackoverflow 中的几篇文章和其他来源）

My Model

我的模特

@Type(type = "fr.mycompany.dao.hibernate.types.ArrayUserType")
private String[] values;

My ArrayUserType

我的 ArrayUserType

public class ArrayUserType implements UserType {

/** Constante contenant le type SQL "Array".
 */
protected static final int[] SQL_TYPES = { Types.ARRAY };

/**
 * Return the SQL type codes for the columns mapped by this type. The
 * codes are defined on <tt>java.sql.Types</tt>.
 * 
 * @return int[] the typecodes
 * @see java.sql.Types
 */
public final int[] sqlTypes() {
    return SQL_TYPES;
}

/**
 * The class returned by <tt>nullSafeGet()</tt>.
 * 
 * @return Class
 */
public final Class returnedClass() {
    return String[].class;
}

/**
 * Retrieve an instance of the mapped class from a JDBC resultset. Implementors
 * should handle possibility of null values.
 * 
 * @param resultSet a JDBC result set.
 * @param names the column names.
 * @param session SQL en cours.
 * @param owner the containing entity 
 * @return Object
 * @throws org.hibernate.HibernateException exception levée par Hibernate
 * lors de la récupération des données.
 * @throws java.sql.SQLException exception SQL 
 * levées lors de la récupération des données.
 */
@Override
public final Object nullSafeGet(
        final ResultSet resultSet, 
        final String[] names, 
        final SessionImplementor session, 
        final Object owner) throws HibernateException, SQLException {
    if (resultSet.wasNull()) {
        return null;
    }

    String[] array = (String[]) resultSet.getArray(names[0]).getArray();
    return array;
}

/**
 * Write an instance of the mapped class to a prepared statement. Implementors
 * should handle possibility of null values. A multi-column type should be written
 * to parameters starting from <tt>index</tt>.
 * 
 * @param statement a JDBC prepared statement.
 * @param value the object to write
 * @param index statement parameter index
 * @param session sql en cours
 * @throws org.hibernate.HibernateException exception levée par Hibernate
 * lors de la récupération des données.
 * @throws java.sql.SQLException exception SQL 
 * levées lors de la récupération des données.
 */
@Override
public final void nullSafeSet(final PreparedStatement statement, final Object value, 
        final int index, final SessionImplementor session) throws HibernateException, SQLException {

    if (value == null) {
        statement.setNull(index, SQL_TYPES[0]);
    } else {
        String[] castObject = (String[]) value;
        Array array = session.connection().createArrayOf("text", castObject);
        statement.setArray(index, array);
    }
}

@Override
public final Object deepCopy(final Object value) throws HibernateException {
    return value;
}

@Override
public final boolean isMutable() {
    return false;
}

@Override
public final Object assemble(final Serializable arg0, final Object arg1)
        throws HibernateException {
    // TODO Auto-generated method stub
    return null;
}

@Override
public final Serializable disassemble(final Object arg0) throws HibernateException {
    // TODO Auto-generated method stub
    return null;
}

@Override
public final boolean equals(final Object x, final Object y) throws HibernateException {
    if (x == y) {
        return true;
    } else if (x == null || y == null) {
        return false;
    } else {
        return x.equals(y);
    }
}

@Override
public final int hashCode(final Object x) throws HibernateException {
    return x.hashCode();
}

@Override
public final Object replace(
    final Object original,
    final Object target,
    final Object owner) throws HibernateException {
    return original;
}

}

}

And the last, but least (that's what I missed) : when I need to run SQL Native Query, I have to force the parameter type with the following syntax

最后，但最不重要的（这是我错过的）：当我需要运行 SQL Native Query 时，我必须使用以下语法强制参数类型

String[] values = ...
Type arrayType = new CustomType(new ArrayUserType());
query.setParameter("value", values, arrayType);