java 三级联动 - Java知识

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1, 先看数据库中存储的结构

2,JDK8 生成层级关系

BaseResult<List<JtlSysDictDTO>> searchRes = jtlSysDictService.findList(param);

if ("area_type".equals(param.getType())) {
List<AreaTree> treeList = searchRes.getValue().stream()
.filter(area -> !area.getValue().equals(area.getParentId()))
.map(area -> {
AreaTree node = new AreaTree();
 node.setValue(area.getValue());
 node.setParentId(area.getParentId());
 node.setLabel(area.getLabel());
 node.setLevel(area.getLevel());
 return node;
 }).collect(Collectors.toList());
 return BaseResult.successWithData(TreeUtil.bulidArea(treeList, "0"));
} else {
return searchRes;
}

工具类：

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

public class TreeUtil {
/**
 * 两层循环实现建树
 *
 * @param treeNodes 传入的树节点列表
 * @return
 */
 public static <T extends TreeNode> List<T> bulid(List<T> treeNodes, Integer root) {
List<T> trees = new ArrayList<>();

 for (T treeNode : treeNodes) {
if (root.intValue() == treeNode.getParentId().intValue()) {
trees.add(treeNode);
 }
for (T it : treeNodes) {
if (it.getParentId().intValue() == treeNode.getId().intValue()) {
if (treeNode.getChildren() == null) {
treeNode.setChildren(new ArrayList<>());
 }
treeNode.add(it);
 }
}
}
return trees;
 }
/**
 * 两层循环实现建树
 *
 * @param treeNodes 传入的树节点列表
 * @return
 */
 public static <T extends AreaNode> List<T> bulidArea(List<T> treeNodes, Object root) {
List<T> trees = new ArrayList<>();

 for (T treeNode : treeNodes) {
if (root.equals(treeNode.getParentId())) {
trees.add(treeNode);
 }
for (T it : treeNodes) {
if (it.getParentId().equals(treeNode.getValue())) {
if (treeNode.getChildren() == null) {
treeNode.setChildren(new ArrayList<>());
 }
treeNode.add(it);
 }
}
}
return trees;
 }
/**
 * 使用递归方法建树
 *
 * @param treeNodes
 * @return
 */
 public static <T extends TreeNode> List<T> buildByRecursive(List<T> treeNodes, Object root) {
List<T> trees = new ArrayList<T>();
 for (T treeNode : treeNodes) {
if (root.equals(treeNode.getParentId())) {
trees.add(findChildren(treeNode, treeNodes));
 }
}
return trees;
 }
/**
 * 递归查找子节点
 *
 * @param treeNodes
 * @return
 */
 public static <T extends TreeNode> T findChildren(T treeNode, List<T> treeNodes) {
for (T it : treeNodes) {
if (treeNode.getId().equals(it.getParentId())) {
if (treeNode.getChildren() == null) {
treeNode.setChildren(new ArrayList<>());
 }
treeNode.add(findChildren(it, treeNodes));
 }
}
return treeNode;
 }

public class AreaTree extends AreaNode {
private String label;
 private String value;
 private String parentId;
 private String level;

 public String getValue() {
return value;
 }
public void setValue(String value) {
this.value = value;
 }
public String getLabel() {
return label;
 }
public void setLabel(String label) {
this.label = label;
 }
public String getParentId() {
return parentId;
 }
public void setParentId(String parentId) {
this.parentId = parentId;
 }
public String getLevel() {
return level;
 }
public void setLevel(String level) {
this.level = level;
 }
public AreaTree() {
}
public AreaTree(String value, String label, String parentId, String level) {
this.value = value;
 this.parentId = parentId;
 this.label = label;
 this.level = level;
 }
}

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

public class AreaNode {
protected String value;
 protected String parentId;
 protected List<AreaNode> children = new ArrayList<AreaNode>();
 protected String lable;

 public String getLable() {
return lable;
 }
public void setLable(String lable) {
this.lable = lable;
 }
public String getValue() {
return value;
 }
public void setValue(String value) {
this.value = value;
 }
public String getParentId() {
return parentId;
 }
public void setParentId(String parentId) {
this.parentId = parentId;
 }
public List<AreaNode> getChildren() {
return children;
 }
public void setChildren(List<AreaNode> children) {
this.children = children;
 }
public void add(AreaNode node) {
children.add(node);
 }
}

3 注意了这个里边写的就是主要的方法

BaseResult result = new BaseResult();
CloudUser user = SecurityUtils.getUser();
if (null == user) {
return BaseResult.error("请登录后操作");
}
List<AreaTreeVo> areaList = new ArrayList<>();
List<JtlCompanyDTO> listCompany = new ArrayList<>();
List<String> regionIds = new ArrayList<>();
BaseResult<List<JtlCompanyDTO>> myChirldIndustrialOrgList = companyService.getMyChirldIndustrialOrgList(user.getOrgId(), orgName, industryType, orgStatus);
if (myChirldIndustrialOrgList.isSuccess() && !CollectionUtils.isEmpty(myChirldIndustrialOrgList.getValue())) {
List<JtlCompanyDTO> values = myChirldIndustrialOrgList.getValue();

 for (JtlCompanyDTO org : values) {
regionIds.add(org.getRegionId());
 listCompany.add(org);
 }
//查询省市县 树形的
 BaseResult<List<AreaTreeVo>> list1 = sysDictService.findAreaList();
 if (list1.isSuccess() && !CollectionUtils.isEmpty(list1.getValue())) {
List<AreaTreeVo> value = list1.getValue();
 value.stream().forEach(areaTreeVo -> { //省

 List<AreaNodeVo> areaNodeVos = new ArrayList<>();
 areaTreeVo.getChildren().stream().forEach(areaNodeVo -> { //市

 List<AreaNodeVo> areaNodeVos2 = new ArrayList<>();
 areaNodeVo.getChildren().stream().forEach(areaNodeVo1 -> { //县

 //如果包含的有的话只需要把单位名称放到返回值中
 if (regionIds.contains(areaNodeVo1.getValue())) {
List<CompanyDto> companyDtos2 = new ArrayList<>();
 //便利单位信息 获取
 for (JtlCompanyDTO companyDTO : listCompany) {
if (areaNodeVo1.getValue().equals(companyDTO.getRegionId())) {
regionIds.remove(companyDTO.getRegionId());
 CompanyDto dto = new CompanyDto();
 dto.setCompanyId(companyDTO.getId());
 dto.setCompanyName(companyDTO.getOrgName());
 dto.setReginId(companyDTO.getRegionId());
 dto.setPosition(companyDTO.getPosition());
 dto.setDeviceState(companyDTO.getOrgState());
 dto.setIndustryTypeName(companyDTO.getIndustryTypeName());
 companyDtos2.add(dto);
 areaNodeVo1.setCompanyDtos(companyDtos2);
 }
}
areaNodeVos2.add(areaNodeVo1);
 areaNodeVo.setChildren(areaNodeVos2);
 }
});
 if (!CollectionUtils.isEmpty(areaNodeVos2)) {
areaNodeVos.add(areaNodeVo);
 areaTreeVo.setChildren(areaNodeVos);
 }
});
 if (!CollectionUtils.isEmpty(areaNodeVos)) {
areaList.add(areaTreeVo);
 }
});
 }
}
result.setSuccess(true);
result.setValue(areaList);
return result;

返回的结果

@Data
public class AreaTreeVo extends AreaNodeVo {
private String label;

 private String value;

 private String parentId;

 private String level;
}

@Data
public class AreaNodeVo extends CompanyDto{ // 这个地方注意了
private String value;

 private String parentId;

 private String label;

 private List<AreaNodeVo> children = new ArrayList<>();

}

public class CompanyDto {
/*
 单位名称
 */
 private String companyName;
 /*
 单位id
 */
 private Long companyId;

 // 管控策略
 private String strategy;

 //单位状态
 private Integer deviceState;

 // 行业类型
 private String industryTypeName;

 // 经纬度
 private String position;

 private String reginId;

 @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss", timezone = "GMT+8")
protected Date createTime;

 protected List<CompanyDto> companyDtos = new ArrayList<>();
}

就是这样的效果

四级联动