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)