树工具类

public static List<SysDict> buildTree(List<SysDict> list, String pid){
        List<SysDict> treeList = new LinkedList<>();

        for (SysDict sysDict : list) {
            if (sysDict.getParentId().equals(pid)) {
                sysDict.setChild(buildTree(list, sysDict.getId()));
                treeList.add(sysDict);
            }
        }
        return treeList;
    }

import com.baomidou.mybatisplus.annotations.TableField;
import com.baomidou.mybatisplus.annotations.TableName;
import lombok.Data;
import lombok.ToString;

import java.util.ArrayList;
import java.util.List;
import java.util.Objects;

/**
 * <p>
 * 字典表
 * </p>
 *
 * @author stz
 * @since 2019-08-14
 */
@TableName("sys_dict")
@ToString
@Data
public class SysDict extends BaseEntity<String> {

    /**
     * 父级编号
     */
    @TableField("parent_id")
    private String parentId;
}