java8 Optional正确使用姿势

Java 8 如何正确使用 Optional

import lombok.Data;

import lombok.EqualsAndHashCode;

import lombok.ToString;

import org.apache.commons.lang3.StringUtils;

import java.util.Optional;

@Data

@EqualsAndHashCode(exclude={"self"})

@ToString(callSuper=true, exclude="self")

public class PersonDto {

    private Integer id;

    private String name;

    private String password;

    private Double self;

    public boolean validateName1() {

        return StringUtils.equals("hjz", name);

    }

    public static boolean validateName2(String name) {

        return StringUtils.equals("hjz", name);

    }

    public static void main(String[] args) {

        PersonDto personDto = new PersonDto();

        personDto.setName("hjz");

//        String name = Optional.ofNullable(personDto)

//                .map(obj -> obj.getName())

//                .filter(StringUtils::isNotEmpty)

//                .orElseThrow(()->new IllegalArgumentException("The value of param personDto isn't available."));

//        String name = Optional.ofNullable(personDto)

//                .map(obj -> obj.getName())

//                .filter(PersonDto::validateName2)

//                .orElseThrow(()->new IllegalArgumentException("The value of param personDto isn't available."));

        String name = Optional.ofNullable(personDto)

                              .filter(PersonDto::validateName1)

                              .map(obj -> obj.getName())

                              .orElseThrow(()->new IllegalArgumentException("The value of param personDto isn't available."));

        System.out.println(name);

    }

}