策略模式加上InitializingBean的编程实现

场景：最近在写一些接口，发现堆了太多的if…eles，所以通过实现Spring框架的InitializingBean接口，加上策略模式，避免代码里堆了太多if…else

实现思路：

• 实现 ApplicationContextAware 接口，通过该接口获取 Spring 容器
• 实现 InitializingBean 接口，接口中定义的 afterPropertiesSet()，Spring框架进行属性填充之后，将策略类加载到一个list列表里
• 通过对应的标识flag获取对应的策略类，通过策略类调用具体方法

大量的if…else堆积：

if (condition1 || condition2) {
// 具体实现业务
} else if ( condition3 || condition4) {
// 具体业务
} else if (condition5 || condition6) {
// ...
}
...

策略类接口

public interface InfoStrategy {
List<InfoModel> obtainInfo(InfoQeury qeury);
String getType();
}import cn.hutool.core.bean.BeanUtil;
import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;

import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.stereotype.Component;
import org.springframework.stereotype.Service;

import java.util.ArrayList;
import java.util.Collection;
import java.util.EnumMap;
import java.util.List;


@Service
@Slf4j
public class InfoServiceImpl implements InfoService, ApplicationContextAware, InitializingBean {

private List<LInfoStrategy> queryStrategys = new ArrayList<>();
private ApplicationContext applicationContext;

@Override
public List<InfoModel> listInfo(InfoQeury query) {
String type = query.getType();
log.info("传参 Type : {} , Code : {}" , type , code);
return getStrategy(type).obtainInfo(query);
}

@Component
class Strategy1 implements InfoStrategy {
@Override
public List<InfoModel> obtainInfo(InfoQeury qeury) {
// ...
return infos;
}
@Override
public String getType() {
return FlagType.1_FLAG.getCode();
}
}

@Component
class Strategy2 implements InfoStrategy {
@Override
public List<InfoModel> obtainInfo(InfoQeury qeury) {
// ...
return infos;
}
@Override
public String getType() {
return FlagType.2_FLAG.getCode();
}
}

@Component
class Strategy3 implements InfoStrategy {
@Override
public List<InfoModel> obtainInfo(InfoQeury qeury) {
// ...
return infos;
}
@Override
public String getType() {
return FlagType.3_FLAG.getCode();
}
}


private InfoStrategy getStrategy(String strategyName) {
for (InfoStrategy strategy : queryStrategys) {
if (strategy.getType().equals(strategyName)) {
return strategy;
}
}
return null;
}

@Override
public void afterPropertiesSet() throws Exception {
Collection<InfoStrategy> strategys =
applicationContext.getBeansOfType(InfoStrategy.class).values();
queryStrategys.addAll(strategys);
}

@Override
public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
this.applicationContext = applicationContext;
}


}