Question

我试图运行我的junit测试用例，但它显示为nullpointerexception。当我调试它的显示为java.lang.reflect.invocationtargetexception导致null。请帮帮我。

公共班StudentTest {

StudentService stuService;

StudentDAO stuDAO;
StudentVO stuVo;

@Before
public void setUp() throws Exception {
    System.out.println("In Setup");
    stuVo=new StudentVO ();
    stuService=new StudentService();
   stuDAO=Mockito.mock(StudentDAO.class);
    //MockitoAnnotations.initMocks(this);
    stuVo.setStudId("123");
    stuVo.setName("user1");
   Mockito.when(stuDAO.getStudent(stuVo.getStuId())).thenReturn(student);

}

@Test
public void getStudent() throws DataAccessException {
    StudentVO stVO=stuService.getStudent(123)   ;
    Assert.assertEquals("123", stVO.getStuId());
}

}

我的服务类是

public class StudentService {
@Inject
StudentDAO stuDao;
public StudentVo getStudent(String id){
    return stuDao.getStudent(id);
}
public StudentDAO getStuDao() {
    return stuDao;
}
}

失败追踪它只是显示为＆＃34; java.lang.NullPointerException

at com.stu.StudentService.getStudent(StudentService.java:104)
at com.stu.junit.POCJunit.getgetStudent(StudentTest.java:21)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:45)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:42)
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.runners.ParentRunner.runLeaf(ParentRunner.java:263)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:68)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:47)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:231)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:60)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:229)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:50)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:222)
at org.junit.runners.ParentRunner.run(ParentRunner.java:300)
at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50)
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)

Answer 1

您的代码存在一些问题。

首先是你的模拟DAO。测试类中没有名为student的变量。除非您从其他对象转换为stuVO对象，否则这应该是stuVO。无论哪种方式，变量学生都需要在该模拟中定义或替换。

另一件事是你的输入和输出没有意义。您在setter中将StudId设置为“123”，但在断言中将其作为int。您可能在setter或getter中进行转换，但请确保您的类型在断言中匹配。

我刚注意到的另一件事。

您没有在服务中设置模拟DAO。这导致您的空指针，因为您的服务正在尝试调用我假设已自动装入的空DAO上的方法。

试试这个

public class StudentTest {
    @ObjectUnderTest
    StudentService stuService;
    @Inject
    StudentDAO stuDAO;
    StudentVO stuVo;

    @Before
    public void setUp() throws Exception {
        System.out.println("In Setup");
        stuVo=new StudentVO ();   
        stuVo.setStudId("123");
        stuVo.setName("user1");
        Mockito.when(stuDAO.getStudent(stuVo.getStuId())).thenReturn(student);
    }

    @Test
    public void getStudent() throws DataAccessException {
        StudentVO stVO=stuService.getStudent(123)   ;
        Assert.assertEquals("123", stVO.getStuId());
    }
}

Answer 2

我通过下面的代码

解决了这个问题

@Mock
StudentDAO stuDAO;

@InjectMocks
StudentService stuService;

并在setUp（）方法中编写了

 MockitoAnnotations.initMocks(this);

java.lang.reflect.invocationtargetexception在Junit中导致null

2 个答案: