vue - blog开发学习6

1、问题，如下图，使用iviewui中的card导致页面不能出现滚动条（不太会弄，在网上查了一个vue组件vuescroll，因此使用这个做滚动条）

2、安装vuescroll

cnpm install -S vuescroll

https://vuescrolljs.yvescoding.org/zh/guide/getting-started.html#%E5%AE%89%E8%A3%85

3、问题：项目使用的jpa操作数据库，因为postclass和post是多堆多的关系，因此post.java和postclass.java如下，

package com.nxz.blog.entity;

import lombok.Data;
import org.hibernate.annotations.GenericGenerator;

import javax.persistence.*;
import java.util.HashSet;
import java.util.Set;

@Entity
@Data
public class Post {

    @Id
    @GeneratedValue(generator = "system-uuid")
    @GenericGenerator(name = "system-uuid", strategy = "uuid")
    @Column(length = 32)
    private String postId;

    private String postTitle;

    @Lob
    private String postContent;

    /**
     * 摘要，也就是content的前100个字符
     */
    private String postRemark;

    private Long createDate;

    private Long updateDate;

    @ManyToMany(fetch = FetchType.LAZY)
    @JoinTable(name = "post_postclass", joinColumns = {@JoinColumn(name = "post_id")}, inverseJoinColumns = {@JoinColumn(name = "post_class_id")})
    private Set<PostClass> postClasses = new HashSet<>();

}

package com.nxz.blog.entity;

import lombok.Data;
import org.hibernate.annotations.GenericGenerator;

import javax.persistence.*;
import java.util.HashSet;
import java.util.Set;

@Entity
@Data
public class PostClass {

    @Id
    @GeneratedValue(generator = "system-uuid")
    @GenericGenerator(name = "system-uuid", strategy = "uuid")
    @Column(length = 32)
    private String classId;

    @Column(unique = true,length = 50)
    private String className;

    @ManyToMany(mappedBy = "postClasses", fetch = FetchType.LAZY)
    private Set<Post> posts = new HashSet<>();

}

但是当调用post.getPostclasses时会出错，会循环输出一下内容：

HHH000100: Fail-safe cleanup (collections) : [email protected]37b2<[email protected]>
2019-06-11 21:30:16.860  WARN 33728 --- [nio-8888-exec-1] o.h.e.loading.internal.LoadContexts      : HHH000100: Fail-safe cleanup (collections) : [email protected]2b5b<[email protected]>
2019-06-11 21:30:16.860  WARN 33728 --- [nio-8888-exec-1] o.h.e.loading.internal.LoadContexts      : HHH000100: Fail-safe cleanup (collections) : [email protected]60ce<[email protected]>
2019-06-11 21:30:16.860  WARN 33728 --- [nio-8888-exec-1] o.h.e.loading.internal.LoadContexts      : HHH000100: Fail-safe cleanup (collections) : [email protected]d7b1<[email protected]>
2019-06-11 21:30:16.860  WARN 33728 --- [nio-8888-exec-1] o.h.e.loading.internal.LoadContexts      : H

经过查询资料：https://stackoverflow.com/questions/54946083/jpa-bidirectional-mapping-not-fetching-deep-mapped-data

得知，这个应该是lombok注解@Data导致的，具体原因没有查明，把这个注解去掉，同时自己手写get、set方法和tostring方法，就可以了

原文地址：https://www.cnblogs.com/nxzblogs/p/11012633.html