小编Har*_*hal的帖子

我想知道是否有任何方法可以使用java String类在控制台上打印带下划线的文本.

我有以下 3 个域模型对象，其中 appuser 的排名和训练状态如下。Get 调用在返回 JSON 对象的地方工作正常，但在 JPA 中添加模型对象时出现错误。

Cannot handle managed/back reference 'defaultReference': no back reference property found from type [simple type, class com.springboot.model.Rank

`

        package com.springboot.model;

    import javax.persistence.Column;
    import javax.persistence.Entity;
    import javax.persistence.FetchType;
    import javax.persistence.GeneratedValue;
    import static javax.persistence.GenerationType.IDENTITY;
    import javax.persistence.Id;
    import javax.persistence.JoinColumn;
    import javax.persistence.ManyToOne;
    import javax.persistence.Table;

    import com.fasterxml.jackson.annotation.JsonBackReference;
    import com.fasterxml.jackson.annotation.JsonIgnore;
    import com.fasterxml.jackson.annotation.JsonManagedReference;

    @Entity
    @Table(name = "app_user", catalog = "testdb")
    public class AppUser implements java.io.Serializable {

        private Integer id;
        private Rank rank;
        private Trainingstatus trainingstatus;
        private String name;
        private …

我正在寻找Java中链表的基本实现,它具有insert()和remove()方法.

谢谢.