定义接口

public interface EntityHandler extends InitializingBean {
    MatchContentDTO match(MatchEntityDTO matchEntityDTO);
    String supportEntityType();
}

定义抽象类

public abstract class AbstractEntityHandler implements EntityHandler {
    @Override
    public final MatchContentDTO match(MatchEntityDTO matchEntityDTO) {
        EntityHandler specialMatchHandler = getSpecialMatchHandler(matchEntityDTO);
        if (specialMatchHandler != null) {
            return specialMatchHandler.match(matchEntityDTO);
        }
        return doCommonMatch(matchEntityDTO);
    }


    public abstract MatchContentDTO doCommonMatch(MatchEntityDTO matchEntityDTO);


    public EntityHandler getSpecialMatchHandler(MatchEntityDTO matchEntityDTO) {
        return null;
    }

}

定义主处理器

@Service
@Slf4j
public class EntitySystemHandler extends AbstractEntityHandler {

    @Override
    public MatchContentDTO doCommonMatch(MatchEntityDTO matchEntityDTO) {
        log.info("EntitySystemHandler:{}", JSON.toJSONString(matchEntityDTO));
        return new MatchContentDTO();
    }

    @Override
    public String supportEntityType() {
        return this.getClass().getName();
    }

    @Override
    public void afterPropertiesSet() throws Exception {
        EntityFactory.register(this);
    }

    @Override
    public EntityHandler getSpecialMatchHandler(MatchEntityDTO matchEntityDTO) {
        return super.getSpecialMatchHandler(matchEntityDTO);
    }
}

分支处理器

@Service
@Slf4j
public class TimeEntityHandler extends AbstractEntityHandler {

    @Override
    public String supportEntityType() {
        return  this.getClass().getName();
    }

    @Override
    public MatchContentDTO doCommonMatch(MatchEntityDTO matchEntityDTO) {
        log.info("TimeEntityHandler:{}", JSON.toJSONString(matchEntityDTO));
        return new MatchContentDTO();
    }

    @Override
    public void afterPropertiesSet() throws Exception {
        EntityFactory.register(this);
    }
}

定义工厂

public class EntityFactory{

    private static final Map<String, EntityHandler> ENTITY_HANDLER_MAP = new HashMap<>();

    public static EntityHandler getEntityHandler(String entityType){
        return ENTITY_HANDLER_MAP.get(entityType);
    }

    public static void register(EntityHandler handler) {
        if (handler == null) {
            return;
        }
        ENTITY_HANDLER_MAP.put(handler.supportEntityType(), handler);
    }

}

demo

@SpringBootTest
@RunWith(SpringRunner.class)
public class EntityTest {

    @Test
    public  void  getTest(){
        EntityHandler entityHandler = EntityFactory.getEntityHandler("system");
        MatchEntityDTO matchEntityDTO = new MatchEntityDTO();
        entityHandler.match(matchEntityDTO);
    }
}