休止状態：チュートリアルによると、負荷とLazyInitializationException

Question

：http://jpa.ezhibernate.com/Javacode/learn.jsp?tutorial=27hibernateloadvshibernateget、

あなたはloadメソッドの呼び出しでJavaBeanインスタンスを初期化する場合は、あなただけの内、最初の時間のために、そのJavaBeanののプロパティにアクセスすることができますそれが初期化されたトランザクションコンテキスト。

JavaBeanをロードしたトランザクションがコミットされた後にJavaBeanのさまざまなプロパティにアクセスしようとすると、Hibernateはデータベースをヒットするために使用する有効なトランザクションコンテキストを持たないため、LazyInitializationExceptionという例外が発生します。 。

しかし、私の実験では、hibernate 3.6とpostgres 9を使って、例外を全くスローしません。何か不足していますか？ここで

は私のコードです：

import org.hibernate.Session; 


public class AppLoadingEntities { 
    /** 
    * @param args 
    */ 
    public static void main(String[] args) { 
     HibernateUtil.beginTransaction(); 
     Session session = HibernateUtil.getSession(); 

     EntityUser userFromGet = get(session); 
     EntityUser userFromLoad = load(session); 

     // finish the transaction 
     session.getTransaction().commit(); 

     // try fetching field value from entity bean that is fetched via get outside transaction, and it'll be okay 
     System.out.println("userFromGet.getId() : " + userFromGet.getId()); 
     System.out.println("userFromGet.getName() : " + userFromGet.getName()); 

     // fetching field from entity bean that is fetched via load outside transaction, and it'll be errornous 
     // NOTE : but after testing, load seems to be okay, what gives ? ask forums 
     try { 
      System.out.println("userFromLoad.getId() : " + userFromLoad.getId()); 
      System.out.println("userFromLoad.getName() : " + userFromLoad.getName()); 
     } catch(Exception e) { 
      System.out.println("error while fetching entity that is fetched from load : " + e.getMessage()); 
     } 
    } 

    private static EntityUser load(Session session) { 
     EntityUser user = (EntityUser) session.load(EntityUser.class, 1l); 
     return user; 
    } 

    private static EntityUser get(Session session) { 
     // safe to set it to 1, coz the table got recreated at every run of this app 
     EntityUser user = (EntityUser) session.get(EntityUser.class, 1l); 
     return user; 
    } 

} 

そして、ここでは出力です：

82 [main] INFO org.hibernate.annotations.common.Version - Hibernate Commons Annotations 3.2.0.Final 
87 [main] INFO org.hibernate.cfg.Environment - Hibernate 3.6.0.Final 
87 [main] INFO org.hibernate.cfg.Environment - hibernate.properties not found 
90 [main] INFO org.hibernate.cfg.Environment - Bytecode provider name : javassist 
92 [main] INFO org.hibernate.cfg.Environment - using JDK 1.4 java.sql.Timestamp handling 
132 [main] INFO org.hibernate.cfg.Configuration - configuring from resource: /hibernate.cfg.xml 
132 [main] INFO org.hibernate.cfg.Configuration - Configuration resource: /hibernate.cfg.xml 
172 [main] WARN org.hibernate.util.DTDEntityResolver - recognized obsolete hibernate namespace http://hibernate.sourceforge.net/. Use namespace http://www.hibernate.org/dtd/ instead. Refer to Hibernate 3.6 Migration Guide! 
189 [main] INFO org.hibernate.cfg.Configuration - Configured SessionFactory: null 
228 [main] INFO org.hibernate.cfg.AnnotationBinder - Binding entity from annotated class: EntityUser 
254 [main] INFO org.hibernate.cfg.annotations.EntityBinder - Bind entity EntityUser on table MstUser 
285 [main] INFO org.hibernate.cfg.Configuration - Hibernate Validator not found: ignoring 
287 [main] INFO org.hibernate.cfg.search.HibernateSearchEventListenerRegister - Unable to find org.hibernate.search.event.FullTextIndexEventListener on the classpath. Hibernate Search is not enabled. 
291 [main] INFO org.hibernate.connection.DriverManagerConnectionProvider - Using Hibernate built-in connection pool (not for production use!) 
291 [main] INFO org.hibernate.connection.DriverManagerConnectionProvider - Hibernate connection pool size: 20 
291 [main] INFO org.hibernate.connection.DriverManagerConnectionProvider - autocommit mode: false 
300 [main] INFO org.hibernate.connection.DriverManagerConnectionProvider - using driver: org.postgresql.Driver at URL: jdbc:postgresql://localhost:5432/hibernate 
300 [main] INFO org.hibernate.connection.DriverManagerConnectionProvider - connection properties: {user=sofco, password=****} 
369 [main] INFO org.hibernate.cfg.SettingsFactory - Database -> 
     name : PostgreSQL 
    version : 9.0.1 
     major : 9 
     minor : 0 
369 [main] INFO org.hibernate.cfg.SettingsFactory - Driver -> 
     name : PostgreSQL Native Driver 
    version : PostgreSQL 9.0 JDBC4 (build 801) 
     major : 9 
     minor : 0 
386 [main] INFO org.hibernate.dialect.Dialect - Using dialect: org.hibernate.dialect.PostgreSQLDialect 
395 [main] INFO org.hibernate.engine.jdbc.JdbcSupportLoader - Disabling contextual LOB creation as createClob() method threw error : java.lang.reflect.InvocationTargetException 
396 [main] INFO org.hibernate.transaction.TransactionFactoryFactory - Transaction strategy: org.hibernate.transaction.JDBCTransactionFactory 
397 [main] INFO org.hibernate.transaction.TransactionManagerLookupFactory - No TransactionManagerLookup configured (in JTA environment, use of read-write or transactional second-level cache is not recommended) 
397 [main] INFO org.hibernate.cfg.SettingsFactory - Automatic flush during beforeCompletion(): disabled 
397 [main] INFO org.hibernate.cfg.SettingsFactory - Automatic session close at end of transaction: disabled 
397 [main] INFO org.hibernate.cfg.SettingsFactory - JDBC batch size: 15 
397 [main] INFO org.hibernate.cfg.SettingsFactory - JDBC batch updates for versioned data: disabled 
397 [main] INFO org.hibernate.cfg.SettingsFactory - Scrollable result sets: enabled 
397 [main] INFO org.hibernate.cfg.SettingsFactory - JDBC3 getGeneratedKeys(): enabled 
397 [main] INFO org.hibernate.cfg.SettingsFactory - Connection release mode: auto 
398 [main] INFO org.hibernate.cfg.SettingsFactory - Default batch fetch size: 1 
398 [main] INFO org.hibernate.cfg.SettingsFactory - Generate SQL with comments: disabled 
398 [main] INFO org.hibernate.cfg.SettingsFactory - Order SQL updates by primary key: disabled 
398 [main] INFO org.hibernate.cfg.SettingsFactory - Order SQL inserts for batching: disabled 
398 [main] INFO org.hibernate.cfg.SettingsFactory - Query translator: org.hibernate.hql.ast.ASTQueryTranslatorFactory 
398 [main] INFO org.hibernate.hql.ast.ASTQueryTranslatorFactory - Using ASTQueryTranslatorFactory 
399 [main] INFO org.hibernate.cfg.SettingsFactory - Query language substitutions: {} 
399 [main] INFO org.hibernate.cfg.SettingsFactory - JPA-QL strict compliance: disabled 
399 [main] INFO org.hibernate.cfg.SettingsFactory - Second-level cache: enabled 
399 [main] INFO org.hibernate.cfg.SettingsFactory - Query cache: disabled 
399 [main] INFO org.hibernate.cfg.SettingsFactory - Cache region factory : org.hibernate.cache.impl.NoCachingRegionFactory 
399 [main] INFO org.hibernate.cfg.SettingsFactory - Optimize cache for minimal puts: disabled 
399 [main] INFO org.hibernate.cfg.SettingsFactory - Structured second-level cache entries: disabled 
401 [main] INFO org.hibernate.cfg.SettingsFactory - Echoing all SQL to stdout 
402 [main] INFO org.hibernate.cfg.SettingsFactory - Statistics: disabled 
402 [main] INFO org.hibernate.cfg.SettingsFactory - Deleted entity synthetic identifier rollback: disabled 
402 [main] INFO org.hibernate.cfg.SettingsFactory - Default entity-mode: pojo 
402 [main] INFO org.hibernate.cfg.SettingsFactory - Named query checking : enabled 
402 [main] INFO org.hibernate.cfg.SettingsFactory - Check Nullability in Core (should be disabled when Bean Validation is on): enabled 
424 [main] INFO org.hibernate.impl.SessionFactoryImpl - building session factory 
548 [main] INFO org.hibernate.impl.SessionFactoryObjectFactory - Not binding factory to JNDI, no JNDI name configured 
Hibernate: select entityuser0_.id as id0_0_, entityuser0_.name as name0_0_, entityuser0_.password as password0_0_ from MstUser entityuser0_ where entityuser0_.id=? 
Hibernate: select entityuser0_.id as id0_0_, entityuser0_.name as name0_0_, entityuser0_.password as password0_0_ from MstUser entityuser0_ where entityuser0_.id=? 
userFromGet.getId() : 1 
userFromGet.getName() : Albert Kam xzy 
userFromLoad.getId() : 1 
userFromLoad.getName() : Albert Kam xzy 

Answer 1

あなた負荷（...）方法であなたは以下のシステムを持っているので、あなたはその例外が表示されません.out

System.out.println("user fetched with 'load' inside transaction : " + user); 

ご覧のとおり、 toString（）を呼び出して（これは自動的に呼び出されます）そして、ログの中で私はあなたが指定されたプロパティのそれぞれのgetterメソッドを内部的に呼び出すtoString（）メソッドをオーバーライドしたことを意味し、以下が表示されているのが分かります。トランザクションがまだ開いている間に（load（...）メソッドが呼び出された後にトランザクションをコミットしている間に）これがすべて発生しているため、この例外は表示されません。

user fetched with 'load' inside transaction : 1:Albert Kam xzy:abc