pojo類

    package com.easzz.model.entity;

import java.util.List;


public class JsonData {
    private Integer id; //省級id

    private Integer pid; //父id

    private String text; //名稱
    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result
                + ((children == null
 
) ? 0 : children.hashCode());
        result = prime * result + ((disable == null) ? 0 : disable.hashCode());
        result = prime * result + ((id == null) ? 0 : id.hashCode());
        result = prime * result + ((pid == null) ? 0 : pid.hashCode());
        result = prime * result + ((text == null) ? 0
 
 : text.hashCode());
        return result;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (obj == null)
            return false;
        if (getClass() != obj.getClass())
            return false;
        JsonData other = (JsonData) obj;
        if
 
 (children == null) {
            if (other.children != null)
                return false;
        } else if (!children.equals(other.children))
            return false;
        if (disable == null) {
            if (other.disable != null)
                return false;
        } else if (!disable.equals(other.disable))
            return false;
        if (id == null) {
            if (other.id != null)
                return false;
        } else if (!id.equals(other.id))
            return false;
        if (pid == null) {
            if (other.pid != null)
                return false;
        } else if (!pid.equals(other.pid))
            return false;
        if (text == null) {
            if (other.text != null)
                return false;
        } else if (!text.equals(other.text))
            return false;
        return true;
    }

    private Integer disable;
    private List<JsonData> children;

    public Integer getDisable() {
        return disable;
    }

    public void setDisable(Integer disable) {
        this.disable = disable;
    }


    public List<JsonData> getChildren() {
        return children;
    }

    public void setChildren(List<JsonData> children) {
        this.children = children;
    }

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public Integer getPid() {
        return pid;
    }

    public void setPid(Integer pid) {
        this.pid = pid;
    }

    public String getText() {
        return text;
    }

    public void setText(String text) {
        this.text = text == null ? null : text.trim();
    }
}

工具類

public static List<JsonData> removeDuplicate(List<JsonData> list) {
        HashSet<JsonData> h = new HashSet<JsonData>(list);
        list.clear();
        list.addAll(h);
        return list;
    }

操作類

    //獲取父級資料
        List<JsonData> pDatas=new ArrayList<JsonData>();
        for (JsonData jsonData : findByRemovedPid) {
            JsonData pdata = jsonDataService.findByPid(jsonData.getPid());
            pDatas.add(pdata);
        }
        List<JsonData> removeDuplicate = removeDuplicate(pDatas);
        for(int i=0;i<removeDuplicate.size();i++){
            System.out.println(removeDuplicate.get(i).getText());
        }

如果是物件，需要實現hashCode()和equals()方法。