Spring Boot 如何组装一个树结构的数据？

妖狐艹你老母 2022-09-01 08:30 261阅读 0赞

> **导语**  
>   项目中出现需求要求返回一个树结构的数据到页面中，但是再数据库设计的时候我们使用的是id与父id的结构来进行存储的，所以说需要有一个简单的数据结构的转换，那么在Spring Boot中如何实现这种数据类型的转换呢？下面就来看一下。

## Controller 层编写的数据 ##

/** * 获取部门下拉树列表 */
        @GetMapping("/treeselect")
        public AjaxResult treeselect(ZhwyAddressPo  zhwyAddress)
        { 
            Long deptId = SecurityUtils.getLoginUser().getUser().getDeptId();
            zhwyAddress.setPropertyId(String.valueOf(deptId));
            List<ZhwyAddressPo> zhwyAddressList = zhwyAddressService.selectZhwyAddressTreeList(zhwyAddress);
            return AjaxResult.success(zhwyAddressService.buildZhwyTreeSelect(zhwyAddressList));
        }

首先需要获取到List相关的列表数据在将列表数据转换成Tree结构的数据。

## 获取数据列表 ##

<select id="selectZhwyAddressTreeList" parameterType="com.ruoyi.common.core.domain.entity.ZhwyAddressPo" resultMap="ZhwyAddressPo">
            <include refid="selectZhwyAddressVo"/>
            <where>
                <if test="parentId != null and parentId != 0">
                    AND parent_id = #{parentId}
                </if>
                <if test="propertyId != null and propertyId != 0">
                    AND property_id = #{propertyId}
                </if>
                <if test="deptName != null and deptName != ''">
                    AND dept_name like concat('%', #{deptName}, '%')
                </if>
            </where>
    
        </select>

## Service 层获取数据 ##

编写获取树形结构数据接口

public List<TreeSelect> buildZhwyTreeSelect(List<ZhwyAddressPo> zhwyAddressList);
    /** * 构建前端所需要树结构 * * @param depts 部门列表 * @return 树结构列表 */
    public List<ZhwyAddressPo> buildDeptTree(List<ZhwyAddressPo> depts);

实现相关的具体逻辑，将上面查询到的AddressList列表接入到数据中。

@Override
    public List<TreeSelect> buildZhwyTreeSelect(List<ZhwyAddressPo> zhwyAddressList) { 
        List<ZhwyAddressPo> deptTrees = buildDeptTree(zhwyAddressList);
        return deptTrees.stream().map(TreeSelect::new).collect(Collectors.toList());
    }

具体组合树形接口内容

/** * 构建前端所需要树结构 * * @param depts 部门列表 * @return 树结构列表 */
        @Override
        public List<ZhwyAddressPo> buildDeptTree(List<ZhwyAddressPo> depts)
        { 
            List<ZhwyAddressPo> returnList = new ArrayList<ZhwyAddressPo>();
            List<Long> tempList = new ArrayList<Long>();
            for (ZhwyAddressPo dept : depts)
            { 
                tempList.add(dept.getDeptId());
            }
            for (Iterator<ZhwyAddressPo> iterator = depts.iterator(); iterator.hasNext();)
            { 
                ZhwyAddressPo dept = (ZhwyAddressPo) iterator.next();
                // 如果是顶级节点, 遍历该父节点的所有子节点
                if (!tempList.contains(dept.getParentId()))
                { 
                    recursionFn(depts, dept);
                    returnList.add(dept);
                }
            }
            if (returnList.isEmpty())
            { 
                returnList = depts;
            }
            return returnList;
        }
    
        /** * 递归列表 */
        private void recursionFn(List<ZhwyAddressPo> list, ZhwyAddressPo t)
        { 
            // 得到子节点列表
            List<ZhwyAddressPo> childList = getChildList(list, t);
            t.setChildren(childList);
            for (ZhwyAddressPo tChild : childList)
            { 
                if (hasChild(list, tChild))
                { 
                    recursionFn(list, tChild);
                }
            }
        }
    
        /** * 得到子节点列表 */
        private List<ZhwyAddressPo> getChildList(List<ZhwyAddressPo> list, ZhwyAddressPo t)
        { 
            List<ZhwyAddressPo> tlist = new ArrayList<ZhwyAddressPo>();
            Iterator<ZhwyAddressPo> it = list.iterator();
            while (it.hasNext())
            { 
                ZhwyAddressPo n = (ZhwyAddressPo) it.next();
                if (StringUtils.isNotNull(n.getParentId()) && n.getParentId().longValue() == t.getDeptId().longValue())
                { 
                    tlist.add(n);
                }
            }
            return tlist;
        }
    
        /** * 判断是否有子节点 */
        private boolean hasChild(List<ZhwyAddressPo> list, ZhwyAddressPo t)
        { 
            return getChildList(list, t).size() > 0 ? true : false;
        }

**TreeSelect实体类**

import java.io.Serializable;
    import java.util.List;
    import java.util.stream.Collectors;
    import com.fasterxml.jackson.annotation.JsonInclude;
    
    public class TreeSelect implements Serializable
    { 
        private static final long serialVersionUID = 1L;
    
        /** 节点ID */
        private Long id;
    
        /** 节点名称 */
        private String label;
    
        /** 子节点 */
        @JsonInclude(JsonInclude.Include.NON_EMPTY)
        private List<TreeSelect> children;
    
        public TreeSelect()
        { 
    
        }
    
        public TreeSelect(ZhwyAddressPo address){ 
            this.id = address.getDeptId();
            this.label = address.getDeptName();
            this.children = address.getChildren().stream().map(TreeSelect::new).collect(Collectors.toList());
        }
    
    
        public Long getId()
        { 
            return id;
        }
    
        public void setId(Long id)
        { 
            this.id = id;
        }
    
        public String getLabel()
        { 
            return label;
        }
    
        public void setLabel(String label)
        { 
            this.label = label;
        }
    
        public List<TreeSelect> getChildren()
        { 
            return children;
        }
    
        public void setChildren(List<TreeSelect> children)
        { 
            this.children = children;
        }
    }

**实体类**

public class ZhwyAddressPo extends BaseEntity { 
    
    
        @JsonSerialize(using = ToStringSerializer.class)
        private Long deptId;
    
    
        private String deptName;
    
        private Long parentId;
    
        private String addressType;
    
    
        private String addressAddress;
    
    
        private String addressArea;
    
    
        private String propertyId;
    
    
        private String propertyName;
    
        /** 子部门 */
        private List<ZhwyAddressPo> children = new ArrayList<ZhwyAddressPo>();
    
        private String spare1;
    
    
        private String spare2;
    
    
        private String spare3;
    
    
        private String spare4;
    
    
        private String spare5;
    
    
        public Long getDeptId() { 
            return deptId;
        }
    
        public void setDeptId(Long deptId) { 
            this.deptId = deptId;
        }
    
    
        public String getDeptName() { 
            return deptName;
        }
    
        public void setDeptName(String deptName) { 
            this.deptName = deptName;
        }
    
        public Long getParentId() { 
            return parentId;
        }
    
        public void setParentId(Long parentId) { 
            this.parentId = parentId;
        }
    
        public String getAddressType() { 
            return addressType;
        }
    
        public void setAddressType(String addressType) { 
            this.addressType = addressType;
        }
    
        public String getAddressAddress() { 
            return addressAddress;
        }
    
        public void setAddressAddress(String addressAddress) { 
            this.addressAddress = addressAddress;
        }
    
        public String getAddressArea() { 
            return addressArea;
        }
    
        public void setAddressArea(String addressArea) { 
            this.addressArea = addressArea;
        }
    
        public String getPropertyId() { 
            return propertyId;
        }
    
        public void setPropertyId(String propertyId) { 
            this.propertyId = propertyId;
        }
    
        public String getPropertyName() { 
            return propertyName;
        }
    
        public void setPropertyName(String propertyName) { 
            this.propertyName = propertyName;
        }
    
    
        public List<ZhwyAddressPo> getChildren() { 
            return children;
        }
    
        public void setChildren(List<ZhwyAddressPo> children) { 
            this.children = children;
        }
    
        public String getSpare1() { 
            return spare1;
        }
    
        public void setSpare1(String spare1) { 
            this.spare1 = spare1;
        }
    
        public String getSpare2() { 
            return spare2;
        }
    
        public void setSpare2(String spare2) { 
            this.spare2 = spare2;
        }
    
        public String getSpare3() { 
            return spare3;
        }
    
        public void setSpare3(String spare3) { 
            this.spare3 = spare3;
        }
    
        public String getSpare4() { 
            return spare4;
        }
    
        public void setSpare4(String spare4) { 
            this.spare4 = spare4;
        }
    
        public String getSpare5() { 
            return spare5;
        }
    
        public void setSpare5(String spare5) { 
            this.spare5 = spare5;
        }
    }
    
    
    
    public class BaseEntity implements Serializable
    { 
        private static final long serialVersionUID = 1L;
    
        /** 搜索值 */
        private String searchValue;
    
        /** 创建者 */
        private String createBy;
    
        /** 创建时间 */
        @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss")
        private Date createTime;
    
        /** 更新者 */
        private String updateBy;
    
        /** 更新时间 */
        @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss")
        private Date updateTime;
    
        /** 备注 */
        private String remark;
    
        /** 请求参数 */
        private Map<String, Object> params;
    
        public String getSearchValue()
        { 
            return searchValue;
        }
    
        public void setSearchValue(String searchValue)
        { 
            this.searchValue = searchValue;
        }
    
        public String getCreateBy()
        { 
            return createBy;
        }
    
        public void setCreateBy(String createBy)
        { 
            this.createBy = createBy;
        }
    
        public Date getCreateTime()
        { 
            return createTime;
        }
    
        public void setCreateTime(Date createTime)
        { 
            this.createTime = createTime;
        }
    
        public String getUpdateBy()
        { 
            return updateBy;
        }
    
        public void setUpdateBy(String updateBy)
        { 
            this.updateBy = updateBy;
        }
    
        public Date getUpdateTime()
        { 
            return updateTime;
        }
    
        public void setUpdateTime(Date updateTime)
        { 
            this.updateTime = updateTime;
        }
    
        public String getRemark()
        { 
            return remark;
        }
    
        public void setRemark(String remark)
        { 
            this.remark = remark;
        }
    
        public Map<String, Object> getParams()
        { 
            if (params == null)
            { 
                params = new HashMap<>();
            }
            return params;
        }
    
        public void setParams(Map<String, Object> params)
        { 
            this.params = params;
        }
    }