springbootTest类中无法注入service组件(service标了@Service)

需要在test类上面加上这两个注解，不然会无法注入，爆出空指针错误.

需要注意junit的版本。

@SpringBootTest
@RunWith(SpringRunner.class)   // junit4
@ExtendWith(SpringExtension.class)  // junit5
public class Work5Test {
    @Autowired
    private StudentService studentService;
    @Test
    public void testSelect(){
        List allStudent = this.studentService.getAllStudent();
        for(Student student: allStudent){
            System.out.println(student);
        }
    }
}