vue - blog開發學習6

1、問題，如下圖，使用iviewui中的card導致頁面不能出現滾動條（不太會弄，在網上查了一個vue元件vuescroll，因此使用這個做滾動條）

2、安裝vuescroll

cnpm install -S vuescroll

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

3、問題：專案使用的jpa操作資料庫，因為postclass和post是多堆多的關係，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個字元
     */
    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<>();

}

但是當呼叫post.getPostclasses時會出錯，會迴圈輸出一下內容：

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

經過查詢資料：https://stackoverflow.com/questions/54946083/jpa-bidirectional-mapping-not-fetching-deep-mapped-data

得知，這個應該是lombok註解@Data導致的，具體原因沒有查明，把這個註解去掉，同時自己手寫get、set方法和tostring方法，就可以了