lombok-多张照片中的@Builder模式 [英] lombok - @Builder pattern in multiple shots

问题描述

我使用 lombok项目的@Builder，所以请考虑我有以下示例:

I use @Builder of lombok project, so consider I have this example:

@Builder
public class Client {

    private @Getter @Setter Integer id;
    private @Getter @Setter String name;

}

等同于:

public class Client {

    private @Getter @Setter Integer id;
    private @Getter @Setter String name;

    public static class Builder {

        private Integer id;
        private String name;

        private Builder() {
        }

        public Builder id(final Integer value) {
            this.id = value;
            return this;
        }

        public Builder name(final String value) {
            this.name = value;
            return this;
        }

        public Client build() {
            return new Client(this);
        }
    }

    public static Client.Builder builder() {
        return new Client.Builder();
    }

    private Client(final Builder builder) {
        this.id = builder.id;
        this.name = builder.name;
    }
}

当我一次尝试设置所有字段时，没有问题:

When I try to set all the the fields in one shot there are no problem:

public static void main(String[] args) {
    Client client = Client.builder()
            .id(123)
            .name("name")
            .build();
}

输出:

Client{id=123, name=name}

现在，考虑我要多次拍摄.例如:

Now, consider I want to make it in multiple shots. For example:

public static void main(String[] args) {
    Client client = Client.builder()
            .id(123)//<-------------------------- Set just the id
            .build();

    client = Client.builder()
            .name("name")//<--------------------- Set name
            .build();

}

这在逻辑上为id返回null:

Client{id=null, name=name}

通常，没有lombok，我通过在Builder类中添加一个带有相同对象的新构造函数来解决此问题:

Generally, without lombok, I solve this issue with adding a new constructor in the Builder class which take the same object:

public static class Builder {
    // ...
    public Builder(Client client) {
        this.id = client.id;
        this.name = client.name;
    }
    // ...
}

然后我将对象传递给该构造函数:

Then I pass my object to that constructor:

Client client = Client.builder()
        .id(123)
        .build();

client = new Client.Builder(client)//<---------------- Like this 
        .name("name")
        .build();

这解决了我的问题，但是我无法用龙目岛解决它.有什么办法可以解决这个问题?

This solves my issue, but I can't arrive to solve it with lombok. Is there any way to solve this issue?

推荐答案

您可以使用toBuilder属性执行此操作.

You can use the toBuilder property to do that.

@Builder(toBuilder=true)
public class Client {
    private @Getter @Setter Integer id;
    private @Getter @Setter String name;
}

然后您可以像这样使用它

and then you can use it like that

public void main(String[] args){
    Client client = Client.builder()
        .id(123)
        .build();

    client = client.toBuilder()
        .name("name")
        .build();
}

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