Question

这两行之间有什么区别？

return firstName.get();

return firstName;

我应该何时使用其中一种？

这里有两个使用这些行的类：

package application.model;

import javafx.beans.property.StringProperty;

public class Employee {
    private int id;
    private String firstName,lastName;

    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }


    public String getFirstName() {
        return firstName;
    }
    public void setFirstName(String firstName) {
        this.firstName = firstName;
    }


    public String getLastName() {
        return lastName;
    }
    public void setLastName(String lastName) {
        this.lastName = lastName;
    }


    public StringProperty firstNameProperty() {
        return firstName;
    }

}

package ch.makery.address.model;

import java.time.LocalDate;

import javafx.beans.property.IntegerProperty;
import javafx.beans.property.ObjectProperty;
import javafx.beans.property.SimpleIntegerProperty;
import javafx.beans.property.SimpleObjectProperty;
import javafx.beans.property.SimpleStringProperty;
import javafx.beans.property.StringProperty;

/**
 * Model class for a Person.
 *
 * @author Marco Jakob
 */
public class Person {

    private final StringProperty firstName;
    private final StringProperty lastName;
    private final StringProperty street;
    private final IntegerProperty postalCode;
    private final StringProperty city;
    private final ObjectProperty<LocalDate> birthday;

    /**
     * Default constructor.
     */
    public Person() {
        this(null, null);
    }

    /**
     * Constructor with some initial data.
     * 
     * @param firstName
     * @param lastName
     */
    public Person(String firstName, String lastName) {
        this.firstName = new SimpleStringProperty(firstName);
        this.lastName = new SimpleStringProperty(lastName);

        // Some initial dummy data, just for convenient testing.
        this.street = new SimpleStringProperty("some street");
        this.postalCode = new SimpleIntegerProperty(1234);
        this.city = new SimpleStringProperty("some city");
        this.birthday = new SimpleObjectProperty<LocalDate>(LocalDate.of(1999, 2, 21));
    }

    public String getFirstName() {
        return firstName.get();
    }

    public void setFirstName(String firstName) {
        this.firstName.set(firstName);
    }

    public StringProperty firstNameProperty() {
        return firstName;
    }

    public String getLastName() {
        return lastName.get();
    }

    public void setLastName(String lastName) {
        this.lastName.set(lastName);
    }

    public StringProperty lastNameProperty() {
        return lastName;
    }

    public String getStreet() {
        return street.get();
    }

    public void setStreet(String street) {
        this.street.set(street);
    }

    public StringProperty streetProperty() {
        return street;
    }

    public int getPostalCode() {
        return postalCode.get();
    }

    public void setPostalCode(int postalCode) {
        this.postalCode.set(postalCode);
    }

    public IntegerProperty postalCodeProperty() {
        return postalCode;
    }

    public String getCity() {
        return city.get();
    }

    public void setCity(String city) {
        this.city.set(city);
    }

    public StringProperty cityProperty() {
        return city;
    }

    public LocalDate getBirthday() {
        return birthday.get();
    }

    public void setBirthday(LocalDate birthday) {
        this.birthday.set(birthday);
    }

    public ObjectProperty<LocalDate> birthdayProperty() {
        return birthday;
    }
}

Answer 1

简而言之：这取决于具体情况。

当对象具有方法.get()时，您只能使用get。 String个对象与原语非常相似，它们是一个值，因此可以直接返回（它们根本没有get方法。）

在这里，StringProperty是一个包装（假设）String，这意味着如果你是来自Person类的return firstName;，你会得到一个StringProperty实例，不是String - 很可能在大多数操作中都不能使用。因此，您返回所需的任何数据类型。

请注意，如果您在源类和目标类中使用字符串，则可以直接返回该值，它已经是可用的形式。

Getters：“return firstName.get（）;”之间的区别并且“返回firstName;”

1 个答案: