本篇文章为你整理了优化if...else...语句（优化if else的设计模式）的详细内容，包含有优化if else 优化if else的设计模式 大量的if如何优化 js 优化if else 优化if...else...语句，希望能帮助你了解 优化if...else...语句。
写代码的时候经常遇到这样的场景：根据某个字段值来进行不同的逻辑处理。例如，不同的会员等级在购物时有不同的折扣力度。如果会员的等级很多，那么代码中与之相关的if...elseif...else...会特别长，而且每新增一种等级时需要修改原先的代码。可以用策略模式来优化，消除这种场景下的if...elseif...else...，使代码看起来更优雅。
首先，定义一个接口
/**
* 会员服务
public interface VipService {
void handle();
}
然后，定义实现类
/**
* 白银会员
public class SilverVipService implements VipService {
@Override
public void handle() {
System.out.println("白银");
* 黄金会员
public class GoldVipService implements VipService {
@Override
public void handle() {
System.out.println("黄金");
}
最后，定义一个工厂类，目的是当传入一个会员等级后，返回其对应的处理类
public class VipServiceFactory {
private static Map String, VipService vipMap = new ConcurrentHashMap ();
public static void register(String type, VipService service) {
vipMap.put(type, service);
public static VipService getService(String type) {
return vipMap.get(type);
}
为了建立会员等级和与之对应的处理类之间的映射关系，这里通常可以有这么几种处理方式：
方式一：实现类手动注册
可以实现InitializingBean接口，或者在某个方法上加@PostConstruct注解
import org.springframework.beans.factory.InitializingBean;
import org.springframework.stereotype.Component;
* 白银会员
@Component
public class SilverVipService implements VipService, InitializingBean {
@Override
public void handle() {
System.out.println("白银");
@Override
public void afterPropertiesSet() throws Exception {
VipServiceFactory.register("silver", this);
* 黄金会员
@Component
public class GoldVipService implements VipService, InitializingBean {
@Override
public void handle() {
System.out.println("黄金");
@Override
public void afterPropertiesSet() throws Exception {
VipServiceFactory.register("gold", this);
}
方式二：从Spring容器中直接获取Bean
public interface VipService {
void handle();
String getType();
* 白银会员
@Component
public class SilverVipService implements VipService {
@Override
public void handle() {
System.out.println("白银");
@Override
public String getType() {
return "silver";
* 黄金会员
@Component
public class GoldVipService implements VipService {
@Override
public void handle() {
System.out.println("黄金");
@Override
public String getType() {
return "gold";
* 上下文
@Component
public class VipServiceFactory implements ApplicationContextAware {
private static Map String, VipService vipMap = new ConcurrentHashMap ();
@Override
public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
Map String, VipService map = applicationContext.getBeansOfType(VipService.class);
map.values().forEach(service - vipMap.put(service.getType(), service));
public static VipService getService(String type) {
return vipMap.get(type);
* 测试
@SpringBootTest
class DemoApplicationTests {
@Test
void contextLoads() {
VipServiceFactory.getService("silver").handle();
}
方式三：反射+自定义注解
@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
public @interface MemberLevel {
String value();
@MemberLevel("silver")
@Component
public class SilverVipService implements VipService {
@Override
public void handle() {
System.out.println("白银");
@MemberLevel("gold")
@Component
public class GoldVipService implements VipService {
@Override
public void handle() {
System.out.println("黄金");
* 上下文
@Component
public class VipServiceFactory implements ApplicationContextAware {
private static Map String, VipService vipMap = new ConcurrentHashMap ();
@Override
public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
// Map String, VipService map = applicationContext.getBeansOfType(VipService.class);
Map String, Object map = applicationContext.getBeansWithAnnotation(MemberLevel.class);
for (Object bean : map.values()) {
if (bean instanceof VipService) {
String type = bean.getClass().getAnnotation(MemberLevel.class).value();
vipMap.put(type, (VipService) bean);
public static VipService getService(String type) {
return vipMap.get(type);
}
完整示例代码
/**
* 结算业务种类
* @Author: ChengJianSheng
* @Date: 2023/1/16
@Getter
public enum SettlementBusiType {
RE1011("RE1011", "转贴现"),
RE4011("RE4011", "买断式贴现"),
RE4021("RE4021", "回购式贴现"),
RE4022("RE4022", "回购式贴现赎回");
// ......
private String code;
private String name;
SettlementBusiType(String code, String name) {
this.code = code;
this.name = name;
@Component
public class DefaultSettlementHandler implements /*SettlementHandler,*/ ApplicationContextAware {
private static Map SettlementBusiType, SettlementHandler allHandlerMap = new ConcurrentHashMap ();
public static SettlementHandler getHandler(SettlementBusiType busiType) {
return allHandlerMap.get(busiType);
@Override
public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
Map String, SettlementHandler map = applicationContext.getBeansOfType(SettlementHandler.class);
map.values().forEach(e - allHandlerMap.put(e.getBusiType(), e));
// 收到结算结果通知，根据业务种类进行结算处理
SettlementHandler handler = DefaultSettlementHandler.getHandler(SettlementBusiType.RE1011);
if (null != handler) {
handler.handle();
}
以上就是优化if...else...语句（优化if else的设计模式）的详细内容，想要了解更多 优化if...else...语句的内容，请持续关注盛行IT软件开发工作室。
郑重声明：本文由网友发布，不代表盛行IT的观点，版权归原作者所有，仅为传播更多信息之目的，如有侵权请联系，我们将第一时间修改或删除，多谢。