标签：parentId tac color depend boolean type templates map lse
package com.ytkj.rose.util;
import org.springframework.util.StringUtils;
import javax.validation.constraints.NotNull;
import java.lang.reflect.Field;
import java.util.ArrayList;
import java.util.Collection;
import java.util.HashSet;
import java.util.Set;
public class TreeUtils {
/**
* 集合转树结构
*
* @param collection 目标集合
* @param clazz 集合元素类型
* @return 转换后的树形结构
*/
public static Collection toTree(@NotNull Collection collection, @NotNull Class clazz) {
return toTree(collection, null, null, null, clazz);
}
/**
* 集合转树结构
*
* @param collection 目标集合
* @param id 节点编号字段名称
* @param parent 父节点编号字段名称
* @param children 子节点集合属性名称
* @param clazz 集合元素类型
* @return 转换后的树形结构
*/
public static Collection toTree(@NotNull Collection collection, String id, String parent, String children, @NotNull Class clazz) {
try {
if (collection == null || collection.isEmpty()) return null;// 如果目标集合为空,直接返回一个空树
if (StringUtils.isEmpty(id)) id = "id"; // 如果被依赖字段名称为空则默认为id
if (StringUtils.isEmpty(parent)) parent = "parent"; // 如果依赖字段为空则默认为parent
if (StringUtils.isEmpty(children)) children = "children"; // 如果子节点集合属性名称为空则默认为children
// 初始化根节点集合, 支持 Set 和 List
Collection roots;
if (collection.getClass().isAssignableFrom(Set.class)) {
roots = new HashSet();
} else {
roots = new ArrayList();
}
// 获取 id 字段, 从当前对象或其父类
Field idField;
try {
idField = clazz.getDeclaredField(id);
} catch (NoSuchFieldException e1) {
idField = clazz.getSuperclass().getDeclaredField(id);
}
// 获取 parentId 字段, 从当前对象或其父类
Field parentField;
try {
parentField = clazz.getDeclaredField(parent);
} catch (NoSuchFieldException e1) {
parentField = clazz.getSuperclass().getDeclaredField(parent);
}
// 获取 children 字段, 从当前对象或其父类
Field childrenField;
try {
childrenField = clazz.getDeclaredField(children);
} catch (NoSuchFieldException e1) {
childrenField = clazz.getSuperclass().getDeclaredField(children);
}
// 设置为可访问
idField.setAccessible(true);
parentField.setAccessible(true);
childrenField.setAccessible(true);
// 找出所有的根节点
for (T c : collection) {
Object parentId = parentField.get(c);
if (isRootNode(parentId)) {
roots.add(c);
}
}
// 从目标集合移除所有根节点
collection.removeAll(roots);
// 遍历根节点, 依次添加子节点
for (T root : roots) {
addChild(root, collection, idField, parentField, childrenField);
}
// 关闭可访问
idField.setAccessible(false);
parentField.setAccessible(false);
childrenField.setAccessible(false);
return roots;
} catch (Exception e) {
e.printStackTrace();
throw new RuntimeException(e);
}
}
/**
* 为目标节点添加孩子节点
*
* @param node 目标节点
* @param collection 目标集合
* @param idField ID 字段
* @param parentField 父节点字段
* @param childrenField 字节点字段
*/
private static void addChild(@NotNull T node, @NotNull Collection collection, @NotNull Field idField, @NotNull Field parentField, @NotNull Field childrenField) throws IllegalAccessException {
Object id = idField.get(node);
Collection children = (Collection) childrenField.get(node);
// 如果子节点的集合为 null, 初始化孩子集合
if (children == null) {
if (collection.getClass().isAssignableFrom(Set.class)) {
children = new HashSet();
} else children = new ArrayList();
}
for (T t : collection) {
Object o = parentField.get(t);
if (id.equals(o)) {
// 将当前节点添加到目标节点的孩子节点
children.add(t);
// 重设目标节点的孩子节点集合,这里必须重设,因为如果目标节点的孩子节点是null的话,这样是没有地址的,就会造成数据丢失,所以必须重设,如果目标节点所在类的孩子节点初始化为一个空集合,而不是null,则可以不需要这一步,因为java一切皆指针
childrenField.set(node, children);
// 递归添加孩子节点
addChild(t, collection, idField, parentField, childrenField);
}
}
}
/**
* 判断是否是根节点, 判断方式为: 父节点编号为空或为 0, 则认为是根节点. 此处的判断应根据自己的业务数据而定.
* @param parentId 父节点编号
* @return 是否是根节点
*/
private static boolean isRootNode(Object parentId) {
boolean flag = false;
if (parentId == null) {
flag = true;
} else if (parentId instanceof String && (StringUtils.isEmpty(parentId) || parentId.equals("0"))) {
flag = true;
} else if (parentId instanceof Integer && Integer.valueOf(0).equals(parentId)) {
flag = true;
}
return flag;
}
}
javax.validation
validation-api
2.0.1.Final
bean:
package com.ytkj.rose.bean;
import java.util.ArrayList;
import java.util.List;
public class TMenu {
private Integer id;
private Integer pid;
private String name;
private String icon;
private String url;
private List children=new ArrayList();
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 getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getIcon() {
return icon;
}
public void setIcon(String icon) {
this.icon = icon;
}
public String getUrl() {
return url;
}
public void setUrl(String url) {
this.url = url;
}
public List getChildren() {
return children;
}
public void setChildren(List children) {
this.children = children;
}
@Override
public String toString() {
return "TMenu{" +
"id=" + id +
", pid=" + pid +
", name=‘" + name + ‘\‘‘ +
", icon=‘" + icon + ‘\‘‘ +
", url=‘" + url + ‘\‘‘ +
", children=" + children +
‘}‘;
}
}
controller:
@RequestMapping("/main")
public String main(HttpSession session) {
logger.debug("跳转到主面");
List menuList=tMenuService.getMenuAll();
session.setAttribute("menuList",menuList);
return "main";
}
service:
package com.ytkj.rose.service;
import com.ytkj.rose.bean.TMenu;
import java.util.List;
public interface TMenuService {
List getMenuAll();
}
serviceImpl
package com.ytkj.rose.service.impl;
import com.ytkj.rose.bean.TMenu;
import com.ytkj.rose.mapper.TMenuMapper;
import com.ytkj.rose.service.TMenuService;
import com.ytkj.rose.util.TreeUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import java.util.*;
@Service
public class TMenuServiceImpl implements TMenuService {
Logger logger= LoggerFactory.getLogger(TAdminServiceImpl.class);
@Autowired
TMenuMapper tMenuMapper;
@Override
public List getMenuAll() {
List list = tMenuMapper.selectAll();
Collection tMenus = TreeUtils.toTree(list, "id", "pid", "children", TMenu.class);
logger.debug("菜单={}",tMenus);
return (List) tMenus;
}
}
mapper:
package com.ytkj.rose.mapper;
import com.ytkj.rose.bean.TMenu;
import java.util.List;
public interface TMenuMapper {
List selectAll();
}
mapper.xml
DOCTYPE mapper
PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">
jsp页面：
页面效果：
jsp 树形结构
标签：parentId tac color depend boolean type templates map lse
原文地址：https://www.cnblogs.com/yscec/p/12386835.html