类实现Comparable,定义排序规则
@Entity
@Data
@Table(name = "meta_data")
public class MetaData implements Comparable<MetaData>{
private Integer pid;
@Override
public int compareTo(MetaData o) {
if(this.getPid()==null){
return 1;
}
if(o.getPid()==null){
return 1;
}
return this.getPid()-o.getPid();//升序
//降序 o.getPid()-this.getPid();
}
}
使用Collections.sort(list)排序
Collections.sort(metas);