我用ssh,但是有一些很复杂的查询需要用到sql,我写了如下方法:String sql = "select * from user";
Session s = this.getHibernateTemplate().getSessionFactory().openSession();
Query q = s.createSQLQuery(sql);
List<User> list = q.list();
for(int i=0;i<list.size();i++)
{
System.out.println(list.get(i));
}User是一个普通的类,里面有id,name等属性。我执行方法输出的是:
[Ljava.lang.Object;@1ac1e22
[Ljava.lang.Object;@ee6ad6
[Ljava.lang.Object;@a826da
[Ljava.lang.Object;@18ed77a
[Ljava.lang.Object;@e496ab如果System.out.println(list.get(i).getId());会报异常,请问怎么能输入User里的属性的值
Session s = this.getHibernateTemplate().getSessionFactory().openSession();
Query q = s.createSQLQuery(sql);
List<User> list = q.list();
for(int i=0;i<list.size();i++)
{
System.out.println(list.get(i));
}User是一个普通的类,里面有id,name等属性。我执行方法输出的是:
[Ljava.lang.Object;@1ac1e22
[Ljava.lang.Object;@ee6ad6
[Ljava.lang.Object;@a826da
[Ljava.lang.Object;@18ed77a
[Ljava.lang.Object;@e496ab如果System.out.println(list.get(i).getId());会报异常,请问怎么能输入User里的属性的值
看看有没有加载User的属性
这是懒加载.
String sql = "select {u.*} from user u";
Session s = this.getHibernateTemplate().getSessionFactory().openSession();
Query q = s.createSQLQuery(sql).addEntity("u",User.class);
List<User> list = q.list();
for(int i=0;i<list.size();i++)
{
System.out.println(list.get(i));
}
方案二: 直接用hql="from user"; s.createQuery();
if(list.size()>0){
for(Object obj [] : list){
System.out.println(obj[0].toString());
System.out.println(obj[1].toString());
}
}
List list = q.list();
List<User> listUser = new ArrayList<User>();
for(int i=0;i<list.size();i++)
{
Object[] obj = list.get(i);
User user = new User();
user.setId(obj[0]);
user.setUsername(obj[1]);
// ...
listUser.add(user);
}
强制转换下就可以了
System.out.println(((User)list.get(i)).getId());//默认是object对象,转换成User
Session s = this.getHibernateTemplate().getSessionFactory().openSession();
List<User> list = s.createSQLQuery(sql).addEntity(User.class).list();
for(User user : list)
{
System.out.println(user.getUserName());
}OK了
报如下的错误:
java.lang.ClassCastException: [Ljava.lang.Object; cannot be cast to com.test.bean.User
at com.test.dao.impl.UserDAOImpl.test(UserDAOImpl.java:52)
at com.test.dao.impl.UserDAOImplTest.test(UserDAOImplTest.java:14)
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.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:28)
at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:31)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:73)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:46)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:180)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:41)
at org.junit.runners.ParentRunner$1.evaluate(ParentRunner.java:173)
at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:28)
at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:31)
at org.junit.runners.ParentRunner.run(ParentRunner.java:220)
at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:46)
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)
List<User> list = s.createSQLQuery(sql).addEntity(User.class).list();
这样写才有效,有几位解答者说要修改为System.out.println(((User)list.get(i)).getId());
我试过了,还是无效。
List<User> list = s.createSQLQuery(sql).addEntity(User.class).list();这样才行。、