Spring数据，按嵌套对象的属性查找 [英] Spring data, find by property of a nested object

问题描述

我有以下代码:

@Entity
public class StudentEntity {
    @Id
    private String id;
    private Student student;
    ...
}


public class Student {
    private String name;
    private List<Grade> grades;
}


public class Grade {
    private String className;
    private String grade;
}

我已经建立了一个 spring 数据 mongodb 存储库，我正在尝试创建一个方法，该方法将返回一个基于 className 的 List我作为参数传入.根据我读过的所有内容，我认为以下方法可行:

I've set up a spring data mongodb repository and I'm trying to create a method that will return me a List<Student> based on a className that I pass in as parameter. Based on everything I've read, I assumed that the following would work:

public List<Student> findByStudentGradesClassName(final String className);

但这给出了一个错误，指出参数类型应该是一个 Grade 对象.我真的只想传入一个 String className.

but that gives an error saying that the parameter type should be a Grade object. I really only want to pass in a String className.

这可能吗?

推荐答案

您必须用下划线分隔嵌套字段:

You would have to separate nested fields with underscore:

public List<Student> findByStudent_Grades_ClassName(final String className);

请注意，您仍然必须以大写开头的字段名称.

Note, that you still have to start field names with uppercase.

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