一、序言
在日常一線開發程序中，總有串列轉樹的需求，幾乎是專案的標配，比方說做多級選單、多級目錄、多級分類等，有沒有一種通用且跨專案的解決方式呢？幫助廣大技術朋友給業務瘦身，提高開發效率，
本文將基于Java8的Lambda 運算式和Stream等知識，使用TreeUtils工具類實作一行代碼完成串列轉樹這一通用型需求，本文有配套視頻，傳送門直達，
需要說明的是，本TreeUtils工具類已進行三版優化，能夠勝任生產場景絕大多數串列轉樹的，
二、實戰編碼
1、引入坐標
本坐標地址包含TreeUtils工具類方法，已經發布到Maven中央倉庫，建議使用最新的版本號，本文發布時版本是1.5.8.3，若有最新版本，建議使用最新版本，
學習原始碼的朋友，原始碼直通車
<dependency>
<groupId>xin.altitude.cms</groupId>
<artifactId>ucode-cms-common</artifactId>
<version>1.5.8.3</version>
</dependency>
2、撰寫DO
DO是訪問資料庫物體類，屬于前期準備素材，
@Data
@NoArgsConstructor
@AllArgsConstructor
@TableName(value = "https://www.cnblogs.com/javazhishitupu/p/bu_category3")
public class Category {
private static final long serialVersionUID = 1L;
@TableId(type = IdType.AUTO)
private String id;
private String name;
private String parentId;
private String remark;
@JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss")
private LocalDateTime createTime;
@JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss")
private LocalDateTime updateTime;
public Category(Category category) {
if (Objects.nonNull(category)) {
this.id = category.id;
this.name = category.name;
this.parentId = category.parentId;
this.remark = category.remark;
this.createTime = category.createTime;
this.updateTime = category.updateTime;
}
}
}
3、創建BO
創建BO資料模型用于構造屬性結點
@Data
@NoArgsConstructor
public class CategoryBo {
private String id;
private String name;
private String parentId;
private String remark;
/**
* 孩子結點 名字任意取
*/
private List<CategoryBo> childList;
/**
* 實作Category 轉 CategoryBo
*
* @param category
*/
public CategoryBo(Category category) {
if (Objects.nonNull(category)) {
this.id = category.getId();
this.name = category.getName();
this.parentId = category.getParentId();
this.remark = category.getRemark();
}
}
}
3、呼叫TreeUtils工具類
在服務層呼叫TreeUtils工具類，一行代碼完成轉換，
/**
* 獲取DO中指定的屬性 并構造成樹
* @return
*/
public List<CategoryBo> selectCategory4() {
List<Category> categoryList = this.list();
List<CategoryBo> categoryBoList = EntityUtils.toList(categoryList, CategoryBo::new);
return TreeUtils.createNodeDetail(categoryBoList, "000000", CategoryBo::getId, CategoryBo::getParentId, CategoryBo::getChildList);
}
4、效果展示
原始串列資料
{
"code": 200,
"msg": "操作成功",
"data": [
{
"id": "310000",
"name": "電子商務",
"parentId": "000000",
"remark": "EEEEE",
"createTime": null,
"updateTime": "2021-11-21 11:22:40"
},
{
"id": "310100",
"name": "大宗商品",
"parentId": "310000",
"remark": "JJJJJ",
"createTime": null,
"updateTime": "2021-11-21 11:22:52"
},
{
"id": "310101",
"name": "大宗商品綜合",
"parentId": "310100",
"remark": "IIIII",
"createTime": null,
"updateTime": "2021-11-21 11:22:58"
},
{
"id": "310102",
"name": "鋼鐵類電商",
"parentId": "310100",
"remark": "OOOOO",
"createTime": null,
"updateTime": "2021-11-21 11:23:02"
},
{
"id": "310200",
"name": "綜合電商",
"parentId": "310000",
"remark": "NNNNN",
"createTime": null,
"updateTime": "2021-11-21 11:23:07"
}
]
}
樹狀層次資料
{
"code": 200,
"msg": "操作成功",
"data": [
{
"id": "310000",
"name": "電子商務",
"parentId": "000000",
"remark": "EEEEE",
"childList": [
{
"id": "310100",
"name": "大宗商品",
"parentId": "310000",
"remark": "JJJJJ",
"childList": [
{
"id": "310101",
"name": "大宗商品綜合",
"parentId": "310100",
"remark": "IIIII",
"childList": []
},
{
"id": "310102",
"name": "鋼鐵類電商",
"parentId": "310100",
"remark": "OOOOO",
"childList": []
}
]
},
{
"id": "310200",
"name": "綜合電商",
"parentId": "310000",
"remark": "NNNNN",
"childList": []
}
]
}
]
}
三、小結
通過一個小小的高頻業務場景，抽離業務共性，屏蔽業務細節，實作了通用型業務邏輯的編碼，
希望廣大技術朋友在完成日常開發作業的前提下，能夠進一步打磨代碼，感受編程之美，
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標籤：Java