//通过name来查询UserI对象
public UserI getUserByName(String name) {
UserI user = null;
String hql = "from UserI as u where u.name=?";
org.hibernate.Query query = sessionFactory.getCurrentSession()
.createQuery(hql);
query.setString(0, name);
List<UserI> list = query.list();
if (list.size() < 1) {
user = list.get(0);
}
return user;
}测试方法:
@Test
public void hh(){
ApplicationContext cx = new ClassPathXmlApplicationContext(
"applicationContext.xml");
IUserBiz iUserBiz = (IUserBiz) cx.getBean("userBizImpl");
UserI user =iUserBiz.getUserByName("user1");
System.out.println(user.getId());
}数据中是有想要的数据的,但是查询的时候就报空值错了···请大家帮忙看看···谢谢大家···
在测试的时候报:java.lang.NullPointerException
at com.tanghb.junit.UserBizImplTest.hh(UserBizImplTest.java:54)
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)
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user = list.get(0);
}变成
if (list.size() > 0) {
user = list.get(0);
}
@Test
public void hh(){
ApplicationContext cx = new ClassPathXmlApplicationContext(
"applicationContext.xml");
IUserBiz iUserBiz = (IUserBiz) cx.getBean("userBizImpl");
UserI user =iUserBiz.getUserByName("user1");System.out.println(user.getId());
}
不要上面的那句,就不报错误,如果, 我想要输出,我查询是结果,该怎么样去做呢?
UserI user =iUserBiz.getUserByName("user1");
if(user!=null){
System.out.println(user.getId());}else{
System.out.println("无结果");
}
list.size() < 1的时候才给user赋值,那user不永远都是null吗
<1跟==0有什么区别呢?