Hibernate 中的SessionFactory 初始化为空

[sj307639429]

我用junit测试一个简单的hibernate程序，测试程序如下：

package org.jun.hibernate.model;


import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.AnnotationConfiguration;
import org.hibernate.cfg.Configuration;

import org.jun.hibernate.model.Teacher; //建立的与表对应的类

import org.junit.AfterClass;
import org.junit.BeforeClass;
import org.junit.Test;


public class TeacherTest {
private static SessionFactory sf = null;

@BeforeClass
public static void beforeClass() {
SessionFactory sf = new AnnotationConfiguration().configure().buildSessionFactory();
}

@Test
public void TeacherSave() {
Teacher t = new Teacher();
t.setId(2);
t.setName("t1");
t.setTitle("叫兽");

System.out.println(sf); //这里输出为null；
Session session = sf.openSession();// 这里报“java.lang.NullPointerException”

session.beginTransaction();
session.save(t);
session.getTransaction().commit();
session.close();
}

@AfterClass
public static void afterClass() {
sf.close();
}
}


在初始化SessionFactory时，输出了Configuration 确认了Configuration初始化正常，就是SessionFactory时有问题，请教了~~~

[sj307639429]

代码重写下

package org.jun.hibernate.model;

import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.AnnotationConfiguration;
import org.hibernate.cfg.Configuration;

import org.jun.hibernate.model.Teacher; //建立的与表对应的类

import org.junit.AfterClass;
import org.junit.BeforeClass;
import org.junit.Test;


public class TeacherTest {
	private static SessionFactory sf = null;
	
	@BeforeClass
	public static void beforeClass() {
		SessionFactory sf = new AnnotationConfiguration().configure().buildSessionFactory();
	}
	
	@Test
	public void TeacherSave() {
		Teacher t = new Teacher();
		t.setId(2);
		t.setName("t1");
		t.setTitle("叫兽");
		
		System.out.println(sf);        //这里输出为null；
		Session session = sf.openSession();// 这里报“java.lang.NullPointerException”
		
		session.beginTransaction();
		session.save(t);
		session.getTransaction().commit();
		session.close();
	}
	
	@AfterClass
	public static void afterClass() {
		sf.close();
	}
}

[道光2008]

System.out.println(sf); //这里输出为null；
Session session = sf.openSession();// 这里报“java.lang.NullPointerException”
晕死
你的sf是null，不报空指针错误，那就见鬼啦

public static void beforeClass() {
SessionFactory sf = new AnnotationConfiguration().configure().buildSessionFactory();
}

改为
public static void beforeClass() {
sf = new AnnotationConfiguration().configure().buildSessionFactory();
}

[sjz64472418]

我也犯了这个错！不过我是这样写的，因为文档中的辅助类是这么写的！使用Annotation不用加configure()
不过我的抛的是 'hibernate.dialect' must be set when no Connection avalable
很费解！
SessionFactory sf = new AnnotationConfiguration().buildSessionFactory();

[pengchengjiji]

哈哈，你跟着他做肯定不行啦，因为你run as的时候，是测试testTeacherSave()方法，但是beforeClass()方法根本还没执行，所以你要测试通过，一定要整个类测试，明白了没？