为什么春天找不到我的豆子？

Question

I created an interface and a class:

public interface UserService {
    List<User> listAll();
}

@Transactional
public class DefaultUserService implements UserService {
    private String tableName;
    public List<User> listAll() { someDao.listAllFromTable(tableName); }
    public void setTableName(String tableName) { this.tableName = tableName; }
}

Also in my application context xml file context.xml , I defined:

<bean id="userService" class="mypackage.DefaultUserService">
    <property name="tableName" value="myusers" />
</bean>

Then I want to test the DefaultUserService :

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations = {"classpath:context-test.xml"})
@TransactionConfiguration(transactionManager = "testTransactionManager")
@Transactional
public class UserServiceTest {

    @Autowired
    private DefaultUserService userService;

    @Before
    public void setup() {
        userService.setTableName("mytesttable");
    }
    @Test
    public void test() {
        // test with userService;
        userService.listAll();
    }
}

Notice it uses context-test.xml , which imported the original context.xml :

<import resource="classpath:context.xml"/>

Unfortunately, when the test starts, spring throws exception:

org.springframework.beans.factory.BeanCreationException: 
Error creating bean with name 'mypackage.UserServiceTest': 
Injection of autowired dependencies failed; 
nested exception is org.springframework.beans.factory.BeanCreationException: 
Could not autowire field: 
private mypackage.DefaultUserService mypackage.userService

nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: 
No qualifying bean of type [mypackage.DefaultUserService] found for dependency: 
expected at least 1 bean which qualifies as autowire candidate for this dependency. 
Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}

I'm not sure where is wrong, why spring can't find the bean DefaultUserService I defined?

Answer 1

Try to replace the class DefaultUserService to the interface UserService

public class UserServiceTest {

    @Autowired
    private UserService userService;
    ....

}

Answer 2

It's because @Transactional places the bean is behind a jdk proxy implementing UserService interface, after that the bean is only available as UserService and not DefaultUserService . See https://stackoverflow.com/a/18875681/241986 .

You can try setting the table name with a property placeholder @Value("${someprop}") and define that property in test context, or create another interface that will expose setTableName() , and autowire that helper interface into the test case.

I'm not sure there are any easy solutions of the problem, I think this task can be subsumed under the problem of bean redefinition in Spring test-context framework Spring beans redefinition in unit test environment

Answer 3

您尚未在implementing class为属性tableName定义getter .Spring IOC容器适用于POJO模型