如何使用龙目岛@Builder方法注释

java builder lombok

2022-09-01 16:31:45

我希望有一种简单的方法来构造测试数据，并且发现生成器模式非常适合这里所述。然而，为了减少组件测试中的样板代码，我发现龙目岛项目@Builder是一个很好的候选者。但是，我找不到任何有关如何在方法上使用它的文档或在线示例。我想在某种工厂方法上使用，因为我无法对实现进行任何更改。@Builder

有人可以举个例子说明如何实际使用一种方法吗？@Builder

答案 1

这就是您使用@Builder的方式。

//Employee.Java
import lombok.Builder;
import lombok.ToString;

@Builder
@ToString
public class Employee {
   private final String empName;
   private final int salary;
}

//   Main.java

public class Main {

public static void main(String[] args) {
    Employee emp = Employee.builder().empName("Deendaya").salary(100).build();
    System.out.println(emp);
  }
}

答案 2

使用 on 方法创建和实例。@BuilderDogCat

在此示例中，使用访问器方法（getters）、全 args 构造函数和创建最终的不可变值对象。@Valueequals()hashCode()toString()

import static org.junit.Assert.*;
import lombok.Builder;
import lombok.Value;

import org.junit.Test;

@SuppressWarnings("javadoc")
public class ImmutableAnimals {

    @Builder(builderMethodName = "dogBuilder")
    public static Dog newDog(String color, String barkSound) {
        return new Dog(color, barkSound);
    }

    @Builder(builderMethodName = "catBuilder")
    public static Cat newCat(String color, String meowSound) {
        return new Cat(color, meowSound);
    }

    public static interface Animal {
        String getColor();
    }

    @Value
    public static class Cat implements Animal {
        String color;
        String meowSound;
    }

    @Value
    public static class Dog implements Animal {
        String color;
        String barkSound;
    }

    @Test
    public void testDog() {
        final String expectedBarkSound = "woof";
        final String expectedColor = "brown";

        final Dog dog = ImmutableAnimals.dogBuilder()
            .barkSound(expectedBarkSound)
            .color(expectedColor)
            .build();

        assertEquals(expectedBarkSound, dog.getBarkSound());
        assertEquals(expectedColor, dog.getColor());
    }

    @Test
    public void testCat() {
        final String expectedMeowSound = "purr";
        final String expectedColor = "white";

        final Cat cat = ImmutableAnimals.catBuilder()
            .meowSound(expectedMeowSound)
            .color(expectedColor)
            .build();

        assertEquals(expectedMeowSound, cat.getMeowSound());
        assertEquals(expectedColor, cat.getColor());
    }
}

下面是另一个具有相同域类但使用可变值的示例。但是，一如既往地尽可能支持不可变性。

import static org.junit.Assert.*;
import lombok.Builder;
import lombok.Data;

import org.junit.Test;

@SuppressWarnings("javadoc")
public class MutableAnimals {

    @Builder(builderMethodName = "dogBuilder")
    public static Dog newDog(String color, String barkSound) {
        final Dog dog = new Dog();
        dog.setBarkSound(barkSound);
        dog.setColor(color);
        return dog;
    }

    @Builder(builderMethodName = "catBuilder")
    public static Cat newCat(String color, String meowSound) {
        final Cat cat = new Cat();
        cat.setMeowSound(meowSound);
        cat.setColor(color);
        return cat;
    }

    public static interface Animal {
        String getColor();
    }

    @Data
    public static class Cat implements Animal {
        String color;
        String meowSound;
    }

    @Data
    public static class Dog implements Animal {
        String color;
        String barkSound;
    }

    @Test
    public void testDog() {
        final String expectedBarkSound = "woof";
        final String expectedColor = "brown";

        final Dog dog = MutableAnimals.dogBuilder()
            .barkSound(expectedBarkSound)
            .color(expectedColor)
            .build();

        assertEquals(expectedBarkSound, dog.getBarkSound());
        assertEquals(expectedColor, dog.getColor());
    }

    @Test
    public void testCat() {
        final String expectedMeowSound = "purr";
        final String expectedColor = "white";

        final Cat cat = MutableAnimals.catBuilder()
            .meowSound(expectedMeowSound)
            .color(expectedColor)
            .build();

        assertEquals(expectedMeowSound, cat.getMeowSound());
        assertEquals(expectedColor, cat.getColor());
    }
}