Как использовать функцию CriteriaBuilder.function JPA 2.1 с MySQL «GROUP_CONCAT»?

Question

Я использую JPA 2.1, Hibernate 4.3.6.Final и MySQL 5.5. Я читал JPA 2.1 поддерживает ссылающегося на собственные функции БД, но у меня возникают проблемы, выяснить, как вызвать в MySQL «GROUP_CONCAT.» У меня есть следующий код ...

final CriteriaBuilder builder = m_entityManager.getCriteriaBuilder(); 
final CriteriaQuery criteria = StringUtils.equals(orderByCol, "organization") ? builder.createQuery(Tuple.class) : builder.createQuery(User.class); 
final Root<User> user = criteria.from(User.class); 
    … 
final SetJoin<User, Organization> orgsJoin = orderByRoot.join(User_.organizations, JoinType.LEFT); 
final Expression groupConcatExpr = builder.function("GROUP_CONCAT", String.class, orgsJoin.get(Organization_.name)); 
criteria.select(builder.tuple(user, groupConcatExpr)) 
        .groupBy(user); 
…   
    orderByExpr = orgsJoin.get(Organization_.name); 
    criteria.orderBy(orderByAscending == null || orderByAscending == true ? builder.asc(orderByExpr) : builder.desc(orderByExpr)); 

, но я получаю следующее исключение ...

java.lang.IllegalStateException: No data type for node: org.hibernate.hql.internal.ast.tree.MethodNode 
\-[METHOD_CALL] MethodNode: 'function (GROUP_CONCAT)' 
    +-[METHOD_NAME] IdentNode: 'GROUP_CONCAT' {originalText=GROUP_CONCAT} 
    \-[EXPR_LIST] SqlNode: 'exprList' 
     \-[DOT] DotNode: 'organizati2_.NAME' {propertyName=name,dereferenceType=PRIMITIVE,getPropertyPath=name,path=generatedAlias1.name,tableAlias=organizati2_,className=org.mainco.subco.organization.domain.Organization,classAlias=generatedAlias1} 
     +-[ALIAS_REF] IdentNode: 'organizati2_.id' {alias=generatedAlias1, className=org.mainco.subco.organization.domain.Organization, tableAlias=organizati2_} 
     \-[IDENT] IdentNode: 'name' {originalText=name} 

    at org.hibernate.hql.internal.ast.tree.SelectClause.initializeExplicitSelectClause(SelectClause.java:174) 
    at org.hibernate.hql.internal.ast.HqlSqlWalker.useSelectClause(HqlSqlWalker.java:924) 
    at org.hibernate.hql.internal.ast.HqlSqlWalker.processQuery(HqlSqlWalker.java:692) 
    at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.query(HqlSqlBaseWalker.java:665) 
    at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.selectStatement(HqlSqlBaseWalker.java:301) 
    at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.statement(HqlSqlBaseWalker.java:249) 
    at org.hibernate.hql.internal.ast.QueryTranslatorImpl.analyze(QueryTranslatorImpl.java:278) 
    at org.hibernate.hql.internal.ast.QueryTranslatorImpl.doCompile(QueryTranslatorImpl.java:206) 
    at org.hibernate.hql.internal.ast.QueryTranslatorImpl.compile(QueryTranslatorImpl.java:158) 
    at org.hibernate.engine.query.spi.HQLQueryPlan.<init>(HQLQueryPlan.java:126) 
    at org.hibernate.engine.query.spi.HQLQueryPlan.<init>(HQLQueryPlan.java:88) 
    at org.hibernate.engine.query.spi.QueryPlanCache.getHQLQueryPlan(QueryPlanCache.java:167) 
    at org.hibernate.internal.AbstractSessionImpl.getHQLQueryPlan(AbstractSessionImpl.java:301) 
    at org.hibernate.internal.AbstractSessionImpl.createQuery(AbstractSessionImpl.java:236) 
    at org.hibernate.internal.SessionImpl.createQuery(SessionImpl.java:1800) 
    at org.hibernate.jpa.spi.AbstractEntityManagerImpl.createQuery(AbstractEntityManagerImpl.java:568) 
    at org.hibernate.jpa.criteria.CriteriaQueryImpl$1.buildCompiledQuery(CriteriaQueryImpl.java:336) 
    at org.hibernate.jpa.criteria.compile.CriteriaCompiler.compile(CriteriaCompiler.java:147) 
    at org.hibernate.jpa.spi.AbstractEntityManagerImpl.createQuery(AbstractEntityManagerImpl.java:736) 
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) 
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) 
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) 
    at java.lang.reflect.Method.invoke(Method.java:597) 
    at org.springframework.orm.jpa.SharedEntityManagerCreator$SharedEntityManagerInvocationHandler.invoke(SharedEntityManagerCreator.java:240) 
    at com.sun.proxy.$Proxy68.createQuery(Unknown Source) 
    at org.mainco.subco.user.repo.UserDaoImpl.findUsers(UserDaoImpl.java:120) 
    at org.mainco.subco.user.repo.UserDao2IT.testFindOrderByOrganizationAsc(UserDao2IT.java:624) 
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) 
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) 
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) 
    at java.lang.reflect.Method.invoke(Method.java:597) 
    at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:44) 
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15) 
    at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:41) 
    at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:20) 
    at org.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:74) 
    at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:83) 
    at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:72) 
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:231) 
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:49) 
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:193) 
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:52) 
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:191) 
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:42) 
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:184) 
    at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61) 
    at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:71) 
    at org.junit.runners.ParentRunner.run(ParentRunner.java:236) 
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:174) 
    at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50) 
    at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38) 
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467) 
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683) 
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390) 
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197) 

Answer 1

Для пользователя GROUP_CONCAT в JPA, ниже шаги:

1.) Создать "GroupConcatFunction" класса, как показано ниже:

import java.util.List; 
import org.hibernate.QueryException; 
import org.hibernate.dialect.function.SQLFunction; 
import org.hibernate.engine.spi.Mapping; 
import org.hibernate.engine.spi.SessionFactoryImplementor; 
import org.hibernate.type.StandardBasicTypes; 
import org.hibernate.type.Type; 

public class GroupConcatFunction implements SQLFunction { 

    @Override 
    public boolean hasArguments() { 
     return true; 
    } 

    @Override 
    public boolean hasParenthesesIfNoArguments() { 
     return true; 
    } 

    @Override 
    public Type getReturnType(Type firstArgumentType, Mapping mapping) 
     throws QueryException { 
     return StandardBasicTypes.STRING; 
    } 

    @SuppressWarnings("rawtypes") 
    @Override 
    public String render(Type firstArgumentType, List arguments, 
     SessionFactoryImplementor factory) throws QueryException { 
     if (arguments.size() != 1) { 
      throw new QueryException("group_concat should have only one argument"); 
     } 
     return "group_concat(" + arguments.get(0) + ")"; 
    } 
} 

2.) Мы создадим пользовательский диалект, который будет иметь код, чтобы зарегистрировать нашу функцию GROUP_CONCAT в диалекте:

import org.hibernate.dialect.MySQL5Dialect; 

public class CustomMySql5Dialect extends MySQL5Dialect { 

    public CustomMySql5Dialect() { 
     super(); 
     registerFunction("group_concat", new GroupConcatFunction()); 
    } 
} 

3.) Заменить определение диалекта в persistence.xml с вашим собственным диалектом:

<property name="hibernate.dialect" value="<<pkg name>>.CustomMySql5Dialect" /> 

Теперь вы сможете использовать это в своем критерии запроса.