hibernate inner join lazy="false"

使用inner join子句可以实现内连接，只要两个持久化类对应的两个表的关联字段之间有相符的值，内连接将组合两个表中的连接。内连接在一对多（多对一）的关联中是最常见的一连接。如：

String hql = "select p from Product p inner join p.category"; 

 Query query = session.createQuery(hql); 

 List<Product> list = query.list(); 


   /** 

      * 测试使用内连接 

      */ 

     public void testUseInnerJoin(){ 

          Session session = null; 

           session = HibernateUtils.getCurrentSession(); 

           String hql = "select p from Product p inner join p.category"; 

           Query query = session.createQuery(hql); 

           List<Product> list = query.list(); 

           HibernateUtils.closeSession(session); 

          for(Product obj : list){ 

              System.out.println(obj.toString()); 

          } 

     }

 

这里注意的是要在多一方设置lazy=”false”属性，否则在显示查询结果会抛出迟延加载的异常：

org.hibernate.LazyInitializationException: could not initialize proxy - no Session 

     at org.hibernate.proxy.AbstractLazyInitializer.initialize(AbstractLazyInitializer.java:57) 

     at org.hibernate.proxy.AbstractLazyInitializer.getImplementation(AbstractLazyInitializer.java:111) 

     at org.hibernate.proxy.pojo.cglib.CGLIBLazyInitializer.invoke(CGLIBLazyInitializer.java:150) 

     at com.kkoolerter.hibernate.beans.Category$$EnhancerByCGLIB$$228a9fa6.toString(<generated>) 

     at com.kkoolerter.hibernate.beans.Product.toString(Product.java:67) 

     at HQLTest.testUseInnerJoin(HQLTest.java:144) 

     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 junit.framework.TestCase.runTest(TestCase.java:164) 

     at junit.framework.TestCase.runBare(TestCase.java:130) 

     at junit.framework.TestResult$1.protect(TestResult.java:106) 

     at junit.framework.TestResult.runProtected(TestResult.java:124) 

     at junit.framework.TestResult.run(TestResult.java:109) 

     at junit.framework.TestCase.run(TestCase.java:120) 

     at org.eclipse.jdt.internal.junit.runner.junit3.JUnit3TestReference.run(JUnit3TestReference.java:130) 

     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)