在grails中保存具有多对多关系的对象

class Author {
    static hasMany = [books: Book]
}

class Book {
    static belongsToMany = [authors: Author]
}

// 定义Author域
class Author {
    String name
    static hasMany = [books: Book]
}

// 定义Book域
class Book {
    String title
    static belongsToMany = [authors: Author]
}

// 保存具有多对多关系的对象
def saveAuthorsAndBooks() {
    // 创建作者
    def author1 = new Author(name: "Author 1").save()
    def author2 = new Author(name: "Author 2").save()

    // 创建书籍
    def book1 = new Book(title: "Book 1").save()
    def book2 = new Book(title: "Book 2").save()

    // 建立多对多关系
    author1.addToBooks(book1)
    author1.addToBooks(book2)
    author2.addToBooks(book1)

    // 保存关系
    author1.save()
    author2.save()
}

// 确保在保存对象之前建立了正确的关联
author1.addToBooks(book1)
author1.addToBooks(book2)
author2.addToBooks(book1)

// 保存关系
author1.save()
author2.save()