Java使用函数式接口处理if-else的策略模式- JAVA

常规策略模式示例


public abstract class Strategy {
 
    abstract void doSomething();
}
 
// 策略A
public class AStrategy extends Strategy{
 
    @Override
    void doSomething() {
 
    }
}
 
// 策略B
 
public class BStrategy extends Strategy{
 
    @Override
    void doSomething() {
 
    }
}

函数式接口策略

定义函数方法


@Slf4j
public class Functions {
 
    public String strategyA(String resourceId){
        log.info(resourceId);
        return "A";
    }
 
    public String strategyB(String resourceId){
        log.info(resourceId);
        return "B";
    }
 
    public String strategyC(String resourceId){
        log.info(resourceId);
        return "C";
    }
}

函数策略调用


@Slf4j
public class FunctionStrategy {
 
    private Functions functions = new Functions();
 
    /**
     * 函数式表
     */
    private Map<String, Function<String,String>> strategyMap = new HashMap<>();
 
    /**
     * 初始化函数匹配策略
     */
    public void init(){
        strategyMap.put("A",resourceId->functions.strategyA(resourceId));
        strategyMap.put("B",resourceId->functions.strategyB(resourceId));
        strategyMap.put("C",resourceId->functions.strategyC(resourceId));
    }
 
    /**
     * 获取结果
     * @param resourceId
     * @return
     */
    public String getResult(String resourceId){
        Function<String,String> result = strategyMap.get(resourceId);
        if(null != result){
            return result.apply(resourceId);
        }else{
            new RuntimeException("错误调用");
        }
        return null;
    }
 
    public static void main(String[] args) {
        FunctionStrategy functionStrategy = new FunctionStrategy();
        functionStrategy.init();
        log.debug("->{}",functionStrategy.getResult("A"));
    }
}