java - 使用 spring 加载应用程序上下文时出现异常

Question

我在 Spring 中使用 DI 时遇到问题。我有 3 个类，其中一个是抽象类。我无法添加一项服务而无法添加另一项服务。我遇到了这个异常:

Caused by: java.lang.IllegalStateException: Cannot convert value of type [sun.proxy.$Proxy14 implementing org.toursys.processor.service.Constants,org.springframework.aop.SpringProxy,org.springframework.aop.framework.Advised] to required type [org.toursys.processor.service.GameService] for property 'gameService': no matching editors or conversion strategy found

我真的很绝望为什么它无法转换请帮忙

我的应用程序上下文:

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:context="http://www.springframework.org/schema/context" xmlns:aop="http://www.springframework.org/schema/aop"
    xmlns:oxm="http://www.springframework.org/schema/oxm"
    xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
                      http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd">

    <import resource="repositoryContext.xml" />


    <bean id="abstractService" class="org.toursys.processor.service.AbstractService" abstract="true">
        <property name="tournamentAggregationDao" ref="tournamentAggregationDao" />
    </bean>

    <bean id="gameService" class="org.toursys.processor.service.GameService" parent="abstractService" />

    <bean id="groupService" class="org.toursys.processor.service.GroupService" parent="abstractService">
        <property name="gameService" ref="gameService" />
    </bean>

</beans>

类(class):

public abstract class AbstractService implements Constants {

    protected TournamentAggregationDao tournamentAggregationDao;
    protected final Logger logger = LoggerFactory.getLogger(getClass());

    @Required
    public void setTournamentAggregationDao(TournamentAggregationDao tournamentAggregationDao) {
        this.tournamentAggregationDao = tournamentAggregationDao;
    }
}

--

public class GameService extends AbstractService {


}

--

public class GroupService extends AbstractService {

    private GameService gameService;

    @Required
    public void setGameService(GameService gameService) {
        this.gameService = gameService;
    }
}

更新:

好的，当我删除我的abstractService中的“implements Constants”时，可以摆脱这个异常。现在看起来像:

public abstract class AbstractService { ... }

但我不知道它不能实现接口(interface)，其中只是常量:

public interface Constants {

    int BEST_OF_GAMES = 9;

}

有人可以向我解释一下这种行为吗？

Answer 1

正如您在异常中看到的那样，spring 使用 java 代理:类型为 [sun.proxy.$Proxy14 。

只能为接口(interface)创建 java 代理，而不能为类创建。

以这种方式更改您的代码:

 public interface GameService  {
 }

 public class GameServiceImpl extends AbstractService implements GameService {
 }

和你的bean.xml到

<bean id="gameService" class="org.toursys.processor.service.GameServiceImpl" parent="abstractService" />