使用枚举 (EnumType.STRING) 在实体上使用 LIKE 运算符执行 JPA 查询

Question

I am able to store, retrieve and query entities with enum types (using JPA/Hibernate). The enum fields are annotated with @Enumerated(EnumType.STRING).

Is it possible to do things like "SELECT a FROM MyEntity a WHERE a.myEnum LIKE :param" ?

The idea is to have it match any entity where the enum value string (in DB) matches a pattern like "SYSTEM_%" or "BUSINESS_%".

Thanks for helping out.

--- Update:

When I tried to query with this:

`@Query("SELECT e FROM MyEntity e WHERE e.myEnum LIKE :value")`

Using the values (to indicate match whatever...):

%%

I get this exception:

  Caused by: java.lang.IllegalArgumentException: Parameter value [%%] did not match expected type [mypackage.MyEntity$MyEnum]
        at org.hibernate.ejb.AbstractQueryImpl.validateParameterBinding(AbstractQueryImpl.java:370)
        at org.hibernate.ejb.AbstractQueryImpl.registerParameterBinding(AbstractQueryImpl.java:343)
        at org.hibernate.ejb.QueryImpl.setParameter(QueryImpl.java:374)
        at org.hibernate.ejb.QueryImpl.setParameter(QueryImpl.java:71)

Answer 1

Absolutely. Just use query.setString("param", "BUSINESS_%"); . Note that using setParameter() instead of setString() throws a ClassCastException as Hibernate tries to cast it to an enum, however setString() does exactly what you want.

Answer 2

saidly there is a shortcut in the org.springframework.orm.hibernate3.HibernateTemplate:

protected void applyNamedParameterToQuery(Query queryObject, String paramName, Object value)
        throws HibernateException {

    if (value instanceof Collection) {
        queryObject.setParameterList(paramName, (Collection) value);
    }
    else if (value instanceof Object[]) {
        queryObject.setParameterList(paramName, (Object[]) value);
    }
    else {
        queryObject.setParameter(paramName, value);
    }
}

would be greate if there is an extra else if (value instanceoff String)...

Answer 3

As a workaround you can build a query by concatenating pattern to the query.

em.createQuery("SELECT e FROM MyEntity e WHERE e.myEnum LIKE '" + pattern +"'")

It works with Hibernate as well as Eclipselink.

However don't try this with pattern made from user input because constructing queries this way is vulnerable to sql injection attack.

Answer 4

I ran into the same problem and I did the following:

• define a second attribute mapping to the same db column
• type of that attribute is String
• it is neither updateable nor insertable
• adapt the set methods of the enum attribute
• make the String attribute a readonly property

    @Column(name = "status")
    @Enumerated(EnumType.STRING)
    private StatusEnum status;

    public void setStatus(StatusEnum status) {
        this.status = status;
        this.statusString = status.toString();
    }
    
    @Column(name ="status", updatable = false, insertable = false)
    private String statusString;

Now you can make queries using 'like' against the statusString:

TypedQuery<MyEntity> query = 
    em.createQuery("select e from MyEntity e where e.statusString like 'CLOSED%', MyEntity.class);