1.树形tree的使用 用后台来体现父子节点的关系
然后天用map集合来体现 那么我们先建立一个实体类来体现它们的父子关系把
package com.damei.entity;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
/**
* tree树形的展示的实体类
* @author Administrator
*
*/
public class TreeNode {
private String id;
private String text;
private String iconCls;
/*
* 描述父子节点，用于递归子节点
*/
private List<TreeNode> children = new ArrayList<>();
/*
* 树形菜单得子节点，除了id以及展示文本，有可能还包含跳转页面，或者图片展示 等一系列得描述
*/
private Map<String, Object> attributes = new HashMap<>();
/*
* 提供set get 方法
*/
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
public String getText() {
return text;
}
public void setText(String text) {
this.text = text;
}
public List<TreeNode> getChildren() {
return children;
}
public void setChildren(List<TreeNode> children) {
this.children = children;
}
public Map<String, Object> getAttributes() {
return attributes;
}
public void setAttributes(Map<String, Object> attributes) {
this.attributes = attributes;
}
public String getIconCls() {
return iconCls;
}
public void setIconCls(String iconCls) {
this.iconCls = iconCls;
}
@Override
public String toString() {
return "TreeNode [id=" + id + ", text=" + text + ", iconCls=" + iconCls + ", children=" + children
+ ", attributes=" + attributes + "]";
}
}
之后我们就在dao 方法里面写一个 递归 在者之前我们要导入几个架包（切记：架包要放在项目的webContent下的web-inf中的lib下）
之后我们用map集合写一个通用的查询方法
public List<Map<String, Object>> foreach(ResultSet rs) throws InstantiationException, IllegalAccessException,
SecurityException, IllegalArgumentException, SQLException {
// TODO Auto-generated method stub
/*
*创建一个实体类的实列
*给创建的实体类的属性赋值
*将赋了值得属性加到list集合里去
*/
List<Map<String,Object>> list = new ArrayList<>();
//获取原数据
ResultSetMetaData metaData = rs.getMetaData();
//获取列
int columnCount = metaData.getColumnCount();
Map<String, Object> map = null;
while(rs.next()) {
map = new HashMap<>();
for (int i = 1; i <= columnCount; i++) {
/*
* 获取列与值
*/
map.put(metaData.getColumnName(i), rs.getObject(i));
}
list.add(map);
}
return list;
}
});
}在之后我们在dao层写一个递归的方法 体现树形的父子关系
public class MenuDao extends JsonBaesDao{
/**
* 查询后台需要属性展示的菜单表数据(所有表字段)
* 注意：该数据转换成json对象，是不符合easyui的tree组件展现的json格式
* @param paramMap
* @param pageBean
* @return
* @throws SQLException
* @throws IllegalAccessException
* @throws InstantiationException
*/
public List<Map<String, Object>> menuList(Map<String, String[]> paramMap,PageBean pageBean) throws InstantiationException, IllegalAccessException, SQLException{
String sql = "select * from t_easyui_menu where true";
//当前节点的id
String menuId = JsonUtitls.getPareMap(paramMap,"Menuid");
if(StringUtils.isNotBlank(menuId)) {
sql += " and parentid in ("+menuId+")";
}else {
sql += " and parentid=-1";
}
return super.ExecuteQuery(sql, null);
}
/**
* 直接查出来的数据源是不能直接用于展示的，需要转换成可展示数据
* @param map
* @param treeNode
* @throws SQLException
* @throws IllegalAccessException
* @throws InstantiationException
*/
private void mapToTreeNode(Map<String, Object> map,TreeNode treeNode) throws InstantiationException, IllegalAccessException, SQLException {
//查出来的数据通过map集合赋值给treeNode实体类
treeNode.setId(map.get("Menuid").toString());
treeNode.setText(map.get("Menuname").toString());
treeNode.setIconCls(map.get("iconcls").toString());
treeNode.setAttributes(map);
Map<String, String[]> paraMap = new HashMap<>();
//把当前节点的id当作父id，查出所有的子节点
paraMap.put("Menuid", new String[] {treeNode.getId()});
List<Map<String, Object>> menuList = this.menuList(paraMap, null);
List<TreeNode> treeNodeList = new ArrayList<>();
mapListToTreeNodeList(menuList, treeNodeList);
//设置子节点
treeNode.setChildren(treeNodeList);
}
/**
*
* @param list 用来展示的
* @param treeNodeList 数据库查出来的数据
* @throws SQLException
* @throws IllegalAccessException
* @throws InstantiationException
*/
private void mapListToTreeNodeList(List<Map<String, Object>> list,List<TreeNode> treeNodeList) throws InstantiationException, IllegalAccessException, SQLException {
TreeNode treeNode = null;
for (Map<String, Object> map : list) {
treeNode = new TreeNode();
mapToTreeNode(map, treeNode);
treeNodeList.add(treeNode);
}
}
/**
* 这个的方法的返回值才是符合easyui的tree组件所需要的json格式
* @param paramMap
* @param pageBean
* @return
* @throws InstantiationException
* @throws IllegalAccessException
* @throws SQLException
*/
public List<TreeNode> menuTreeList(Map<String, String[]> paramMap,PageBean pageBean) throws InstantiationException, IllegalAccessException, SQLException{
List<Map<String, Object>> menuList = this.menuList(paramMap, pageBean);
List<TreeNode> treeNodeList = new ArrayList<>();
mapListToTreeNodeList(menuList, treeNodeList);
return treeNodeList;
}
}在action中调用dao层的查询方法来展示树形
/**
* 树形展示
* @param req
* @param resp
* @return
*/
public String menuTreeList(HttpServletRequest req,HttpServletResponse resp) {
try {
List<TreeNode> menuTreeNodeList = this.menuDao.menuTreeList(req.getParameterMap(), null);
//将获取的值转换成json对象格式
ObjectMapper objectMapper = new ObjectMapper();
ResponseUtitls.Writer(resp, objectMapper.writeValueAsString(menuTreeNodeList));
} catch (IllegalArgumentException | IllegalAccessException | InstantiationException | SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (JsonProcessingException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return "index";
}menuTreeNodeList便是在后台js调用的方法 js方法的体现
$(function(){ //程序入口
//获取树形的id
$('#menuTree').tree({
//查询展示树形菜单的url方法
url:'menuAction.action?methodName=menuTreeList&&Menuid='+$("#Menuid").val(),
onClick: function(node){
if(node.attributes.menuURL!=null){
//查询这个tab页是否打开 如果打开了就不能再次打开此tab
if($('#tt').tabs('exists',node.text)){
$('#tt').tabs('select',node.text);
}else{
//没有就增加一个tab页
$('#tt').tabs('add',{
title:node.text,
//拿去数据库的url
content:'<iframe scrolling="no" frameborder="0" src="'+node.attributes.menuURL+'" width="99%" height="99%"></iframe>',
closable:true
});
}
}
}
});
})结果展示
希望有帮助