I. demand

The existing requirement is to show all comments of a post.

Two: analysis

Comments on posts are divided into main comments and sub comments. Main comments are direct comments on posts, and sub comments are comments on comments.

Three: train of thought

First, get all the main comments of a post, recursively judge whether there are sub comments, and get sub comments.

Four: coding

Entity class:

 1 import java.util.Date;
 2 import java.util.List;
 3 
 4 import com.fasterxml.jackson.annotation.JsonFormat;
 5 
 6 import lombok.Data;
 7 @Data
 8 public class BsChannelPostReply {
 9     private long replyId;
10     private String niceName;
11     @JsonFormat(pattern="yyyy-MM-dd HH:mm:ss",timezone = "GMT+8") 
12     private Date replyDate;
13     private String content;
14     private long directRepliedId;//Direct comment of reply replyId
15     private List<BsChannelPostReply> children;//The following sub comments
16 }

Get the main comment list and recurse all the sub comments:

 1 @Override
 2     @Datasource(value="community")//Switch data source
 3     public List<BsChannelPostReply> getMainReply(int postId) {
 4         // TODO Auto-generated method stub
 5         List<BsChannelPostReply> listMain=dao.getMainReply(postId);//Get main comment
 6         if(listMain.size()>=0){//If the main comment is not empty
 7             for (BsChannelPostReply bsChannelPostReply : listMain) {
 8                 bsChannelPostReply.setChildren(getMainReplyChildren(bsChannelPostReply.getReplyId()));//Load subcomments
 9             }
10         }
11         return listMain;
12     }
13 
14     @Override
15     @Datasource(value="community")//Switch data source
16     public List<BsChannelPostReply> getMainReplyChildren(long replyId) {
17         // TODO Auto-generated method stub
18         List<BsChannelPostReply> listChildren=dao.getMainReplyChildren(replyId);//Based on the current replayId Get current level sub comment list
19             if(listChildren.size()>=0){
20             for (BsChannelPostReply bsChannelPostReply : listChildren) {
21                 bsChannelPostReply.setChildren(getMainReplyChildren(bsChannelPostReply.getReplyId()));//When judging whether there are sub comments in the current sub comment, call recursively until there are no sub comments
22             }
23         }
24         return listChildren;
25     }

Five: effect

According to this kind of recursive call, we can get unlimited sub comment list theoretically.