【Feature】新增注解处理对象类型的字段

[BennettChina]

数据结构如下：

@Data
public class Demo {
    private String name;
    private String value;
    
    @ExcelInclude
    private Item item;
}

希望有个注解能处理 item 这种同样是一对一关联数据但进行了数据包装的类型，就如同 @Validated 和 @Valide 的嵌套校验一样，新增一个类似的注解深度读取字段然后跟父类的放在同一行。

[alaahong]

Can you provide the target result of input and output? Not sure the expectation yet.

[BennettChina]

@Data
public class Demo {
    private String name;
    private String value;
    
    @ExcelInclude
    // @ExcelInclude("item")
    private Item item;

    public static class Item {
        private String properties1;
        private String properties2;
    }
}

demo1.xlsx
demo2.xlsx

最开始我期望的是 demo1.xlsx 的结果，现在想是或许可以利用它实现 demo2.xlsx 的合并标题效果，而 demo1.xlsx 可以是默认实现。不过 demo2 的效果实现起来可能比较麻烦，可以先尝试实现 demo1 的效果。

translation:

Initially, I expected the result of demo1.xlsx, but now I'm thinking that perhaps it can be used to achieve the merged header effect of demo2.xlsx, with demo1.xlsx as the default implementation. However, implementing the effect of demo2 might be quite troublesome, so you can first try to implement the effect of demo1.

[bengbengbalabalabeng]

I'd like to propose a design for handling nested objects using a new @ExcelOneToOne annotation to handle nested objects. This would allow flattening the fields of a nested object directly into the columns of the parent object.

Example:

public class Item {
    @ExcelProperty("item name")
    private String name;

    @ExcelProperty("item code")
    private String code;
}

1. Without @ExcelProperty

public class Demo {
    @ExcelProperty("name")
    private String name;

    @ExcelProperty("value")
    private String value;

    @ExcelOneToOne
    private Item item;
}

When a field is marked only with @ExcelOneToOne, its inner fields are treated as top-level columns. like demo1.xlsx

2. With @ExcelProperty

public class Demo {
    @ExcelProperty("name")
    private String name;

    @ExcelProperty("value")
    private String value;

    @ExcelOneToOne
    @ExcelProperty("item")
    private Item item;
}

When the field is marked with both @ExcelOneToOne and @ExcelProperty, the value of @ExcelProperty becomes a parent header, creating a multi-level header. like demo2.xlsx

In the future, we can continue to extend annotations similar to @ExcelOneToMany to handle one-to-many relationships.

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What does everyone think of this approach?