EasyUI_tree根據數據庫數據非迭代生成樹形結構

咱們常常要根據數據庫表的結構，生成樹形結構在頁面顯示；下面就是一個例子：

頁面的tree組件採用的是EasyUI 的 Tree 組件。

 

數據庫結構：

表名稱： tDict

Id      name    parentid    sortid         valid

主鍵       名稱    父ID      排序ID          是否可用

 

 

tDict 實體類中，父ID以 tDict 實體類表述，以下：

 

 
    
    public class TDict{  
  
    // Fields  
  
    private String id;  
    private TDict tDict;  
    private Integer sortid;  
    private String valid;  
    private String name;  
  
   
  
    ……省略<Get & Set>  
  
   
  
}

 

要用到Hibernate的支持，如下是模型層的映射文件 hbm

 
    
    <?xml version="1.0" encoding="utf-8"?>  
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"  
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">  
<!--  
    Mapping file autogenerated by MyEclipse Persistence Tools 
-->  
<hibernate-mapping default-lazy="false">  
    <class name="com.bzinfo.crm.model.TDict" table="T_DICT">  
        <id name="id" type="java.lang.String">  
            <column name="ID" length="50" />  
            <generator class="assigned" />  
        </id>  
        <many-to-one name="tDict" class="com.bzinfo.crm.model.TDict"   lazy="false">  
            <column name="PARENTID" length="50" />  
        </many-to-one>  
        <property name="sortid" type="java.lang.Integer">  
            <column name="SORTID" precision="6" scale="0" />  
        </property>  
        <property name="valid" type="java.lang.String">  
            <column name="VALID" length="1" />  
        </property>  
        <property name="name" type="java.lang.String">  
            <column name="NAME" length="50" />  
        </property>  
</hibernate-mapping>

首先，創建數節點類：

 
    
    import java.util.ArrayList;  
import java.util.HashMap;  
import java.util.List;  
import java.util.Map;  
   
public class TreeNode {  
  
    privateString id;          //要顯示的子節點的ID  
    privateString text;        //要顯示的子節點的 Text  
    privateString iconCls;     //節點的圖標  
    privateString parentId;    //父節點的ID  
    privateList<TreeNode>  children;   //孩子節點的List  
  
    publicTreeNode(){}  
  
    publicTreeNode(String id, String text, String iconCls, String parentId,  
  
           List<TreeNode>children) {  
  
       super();  
       this.id= id;  
       this.text= text;  
       this.iconCls= iconCls;  
       this.parentId= parentId;  
       this.children= children;  
    }  
  
     
  
    publicString getId() {  
  
       returnid;  
  
    }  
  
    publicvoid setId(String id) {  
       this.id= id;  
    }  
  
    publicString getText() {  
       returntext;  
    }  
  
    publicvoid setText(String text) {  
       this.text= text;  
    }  
  
    publicString getIconCls() {  
       returniconCls;  
    }  
  
    publicvoid setIconCls(String iconCls) {  
       this.iconCls= iconCls;  
    }  
  
    publicString getParentId()   
       returnparentId;  
    }  
  
    publicvoid setParentId(String parentId) {  
       this.parentId= parentId;  
    }  
  
    publicList<TreeNode> getChildren() {  
       returnchildren;  
    }  
  
    publicvoid setChildren(List<TreeNode> children) {  
       this.children= children;  
    }  
  
    //添加孩子的方法  
  
    publicvoid addChild(TreeNode node){  
       if(this.children == null){  
           children= new ArrayList<TreeNode>();  
           children.add(node);  
       }else{  
           children.add(node);  
       }  
            
    }  
     
}

下面是生成樹的方法：

 
    
    @SuppressWarnings("unchecked")  
  
    public List fillTree(String tableName){  
  
       String hql = " from TDictt where valid='1' order by t.sortid ";  
       List<TreeNode> list = new ArrayList<TreeNode>();  
       Map map = new HashMap<String, TreeNode>();  
  
       try {  
  
           //拉出數據庫的數據，放入list2中  
  
           ArrayList<TDict> list2 = (ArrayList<TDict>)this.find(hql);               
  
           //將list2中的數據，轉換成TreeNode類型，放入Map中備用  
           for (TDict tDict : list2) {  
              TreeNode node = new TreeNode();  
              node.setId(tDict.getId());  
              node.setText(tDict.getName());  
              if(tDict.gettDict()!=null){  
                    node.setParentId(tDict.gettDict().getId());  
              }  
  
              map.put(tDict.getId(), node);  
  
           }  
  
  
           //遍歷list2的數據，把每一個節點加入他的父節點的孩子List  
  
           for (TDict tDict : list2) {  
  
              if(tDict.gettDict()!= null){  
  
                  if(tDict.gettDict().getId() == null)  
                  {  
                     list.add((TreeNode)map.get(tDict.getId()));  
                  }else{  
  
                     String pidString = tDict.gettDict().getId();  
                     TreeNode pnode = (TreeNode)map.get(pidString);  
                     TreeNode cnode=(TreeNode)map.get(tDict.getId());  
                     pnode.addChild(cnode);  
                  }  
              }else{  
                  list.add((TreeNode)map.get(tDict.getId()));  
              }  
           }           
       }catch (Exception e) {  
                  // TODO: handleexception  
           e.printStackTrace();  
       }  
        return list;  
  
    }

 

在頁面顯示的時候，把list轉換成Json格式：

 
    
    List treeSet = treeManagerImpl.fillTree(null);  
  
 String treeString = gson.toJson(treeSet);  
  
 session.setAttribute("tree", treeString);

在頁面取Json數據，並顯示

 
    
    <script type="text/javascript">  
  
window.onload =function(){  
  
       tree = ${tree};  
  
       $('#tt').tree({   
  
        data:tree   
  
       });   
  
    };  
  
</script>