Tech&WK_SRDC_Project_Think

purpose : techRoad 过程中的点滴思考

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2020-07-04

idom 

1. Optional lambda 处理， 及相关的 API publish （ <java in action 2>  P253）
2. Optional 封装 try - catch , 封装的额OptionalUtility   将 String 转换为 Optional<Integer>  （<J I A > p260 )

package techRoad.java.Optional;

import java.util.Optional;

public class OptionalUtility {

    public static Optional<Integer> stringToInt(String originalStr){       
        try{
            return Optional.of(Integer.parseInt(originalStr));
        }catch (NumberFormatException ex){
            return Optional.empty();
        }
    }
}

    public int readDuration(Properties props, String s) {

            return Optional.ofNullable(props.getProperty(s))
                    .flatMap(OptionalUtility::stringToInt)
                    .filter(i -> i > 0)
                    .orElse(0);
    }