轉自 http://together.javaeye.com/blog/29482?page=2

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在系統中，經常會用到無限級的樹形結構分類，如組織機構管理、商品/地區分類等等。在以前的一個貼子：http://www.javaeye.com/topic/26987“復雜商品分類的表如何建立？”中，討論過樹形無級分類的實現方法。

一般無外采用兩種方式，
　　一是類似struts-menu（http://struts-menu.sourceforge.net）的XML文件管理方式，配置起來比較方便，但很難與系統中其它應用數據集成；
　　二是使用數據庫存儲，定義父子關系。

在我們現在開發的一個產品中，使用hibernate實現了一套樹形結構的處理方法，實現了樹的基本操作，上溯、下溯、子節點的添加/移除和遞歸查找、對象關聯等。簡介如下：
■適用范圍，具有樹形特征的所有對象，如樹形菜單、組織結構、信息分類、論壇主貼與回復等。
■完整源碼下載（內置了hsql數據庫及測試數據，正式使用時請將war置于APPSERVER的webapps目錄下，修改解包后的WEB-INF/classes/hibernate.cfg.xml，編輯其中hsqldb的物理路徑。如jdbc:hsqldb:file:c:/tomcat5/webapps/treetest/db/test）見附件，運行http://ServerName:ServerPort/treetest/menumanage.do。
■樹形結構顯示，使用的是xtree。為便于編輯維護，自己寫了一個左鍵彈出菜單（xtree的右鍵事件無法更改），進行節點的添加、修改、刪除、轉移操作。（PS：這套維護界面是完全跨瀏覽器的，有興趣的不妨一試）
■關聯關系：
可以使用objects對象來配置關聯關系，實現多對多/一對多等關系。在BaseTree中，getObjects()方法是abstract的，可以根據需要自己定義。如論壇分類與每個分類所對應的貼子相關聯，商品分類與商品編碼相關聯等，可以根據需要來處理hbm文件。若需要多項關聯，亦可擴展。如菜單與用戶、部門、崗位分別進行關聯
■hibernate2.1.7的一個bug，在這個測試源碼的dao中，TreeManager的getRoots方法，
session.createQuery(" from " + cls.getName() + " where enabled=? and parent_id is null order by id");
在hibernate2中必須像寫成parent_id is null，才能正確運行，這應該是2.1.7中的一個bug。而hibernate3中，可以使用parent is null的hsql。
■主要代碼：
繼承關系如下，假如要實現國家分類：
CountryTree extends BaseTree(abstract class)
　　　　　　　　　　BaseTree(abstract class) implements Tree(interface)
為節省版面，下面代碼去掉了javadoc
Tree.java

Java代碼

/** ?

?*?實現了樹的基本操作，上溯、下溯、子節點的添加/移除和遞歸查找、對象關聯等 ?

?*/??

package?test.testtree.base; ??

import?java.util.Set; ??

??

public?interface?Tree?{? ??

????public?String?getCode(); ??

????public?String?getName(); ??

????public?String?getDescription(); ??

????public?Tree?getParent(); ??

????public?Set?getParents(); ??

????public?boolean?isRoot(); ??

????public?boolean?isLeaf(); ??

????public?boolean?isParentOf(Tree?tree); ??

????public?boolean?isChildOf(Tree?tree); ??

????public?void?addChild(Tree?tree); ??

????public?void?rmChild(Tree?tree); ??

????public?Set?getAllChildren(); ??

????public?Set?getChildren(); ??

????public?Set?getAllLeaves(); ??

????public?void?addObject(Object?obj); ??

????public?void?rmObject(Object?obj); ??

????public?Set?getObjects(); ??

????public?Long?getId(); ??

}??

/*** 實現了樹的基本操作，上溯、下溯、子節點的添加/移除和遞歸查找、對象關聯等*/ package test.testtree.base; import java.util.Set;public interface Tree { public String getCode();public String getName();public String getDescription();public Tree getParent();public Set getParents();public boolean isRoot();public boolean isLeaf();public boolean isParentOf(Tree tree);public boolean isChildOf(Tree tree);public void addChild(Tree tree);public void rmChild(Tree tree);public Set getAllChildren();public Set getChildren();public Set getAllLeaves();public void addObject(Object obj);public void rmObject(Object obj);public Set getObjects();public Long getId(); }

BaseTree.java

Java代碼

package?test.testtree.base; ??

import?java.util.*; ??

??

public?abstract?class?BaseTree?extends?BasePojo?implements?Tree{???? ??

????protected?String?code;???? ??

????protected?String?name;???? ??

????protected?String?description;???????? ??

????protected?BaseTree?parent;??? ??

????protected?Set?children?=?new?HashSet();???? ??

????protected?Set?objects?=?new?HashSet();???? ??

????public?void?setCode(String?code)?{ ??

????????this.code?=?code; ??

????}???? ??

????abstract?public?String?getCode(); ??

????public?void?setName(String?name)?{ ??

????????this.name?=?name; ??

????}???? ??

????abstract?public?String?getName();???? ??

????public?void?setDescription(String?description)?{ ??

????????this.description?=?description; ??

????} ??

????abstract?public?String?getDescription(); ??

????abstract?public?Tree?getParent();???????? ??

????public?boolean?isRoot()?{ ??

????????return?(getParent()==null); ??

????}???? ??

????public?boolean?isLeaf()?{ ??

????????return?(this.getChildren().size()==0); ??

????}???? ??

????public?boolean?isParentOf(Tree?tree)?{ ??

????????if?(tree==null?||?((BaseTree)?tree).equals(this))?{ ??

????????????/*如果對方為空*/??

????????????return?false; ??

????????}else?if(this.isLeaf()){ ??

????????????/*如果自己為葉子,則返回FALSE*/??

????????????return?false; ??

????????}else?if(tree.isRoot()){ ??

????????????/*如果對方為根,返回FALSE*/??

????????????return?false; ??

????????}else{ ??

????????????BaseTree?bt?=?(BaseTree)?(tree.getParent()); ??

????????????if?(this.equals(bt)){ ??

????????????????/*如果對方的父節點是自己,則返回TRUE*/??

????????????????return?true; ??

????????????}else{ ??

????????????????/*判斷對方的父節點是否是自己的孩子,進行遞歸*/??

????????????????return?isParentOf(bt); ??

????????????} ??

????????} ??

????} ??

????public?boolean?isChildOf(Tree?tree)?{ ??

????????return?(tree.isParentOf(this)); ??

????} ??

????public?void?addChild(Tree?tree)?{ ??

????????children.add(tree); ??

????} ??

????public?void?rmChild(Tree?tree)?{ ??

????????children.remove(tree); ??

????????((BaseTree)?tree).setParent(null); ??

????} ??

????public?Set?getAllLeaves()?{ ??

????????Set?set_old?=?this.getAllChildren(); ??

????????Set?set?=?new?HashSet(); ??

????????set.addAll(set_old); ??

????????Iterator?itr?=?set_old.iterator(); ??

????????while(itr.hasNext()){ ??

????????????BaseTree?bt?=?(BaseTree)?itr.next(); ??

????????????if?(!?bt.isLeaf()){ ??

????????????????set.remove(bt); ??

????????????} ??

????????} ??

????????return?set; ??

????} ??

???public?Set?getParents(){ ??

????????Set?parents?=?new?HashSet();???????? ??

????????Tree?p?=?this.getParent(); ??

????????if(p!=null){ ??

????????????parents.add(p); ??

????????????parents.addAll(p.getParents()); ??

????????} ??

????????return?parents; ??

????} ??

??

????public?Set?getAllChildren()?{ ??

????????Set?set?=?new?HashSet(); ??

????????Stack?stack?=?new?Stack(); ??

????????stack.push(this); ??

????????while(!stack.empty()){ ??

????????????BaseTree?bt?=?(BaseTree)?stack.pop(); ??

????????????set.add(bt); ??

????????????Iterator?itr?=?bt.getChildren().iterator(); ??

????????????while(itr.hasNext()){ ??

????????????????BaseTree?btchild?=?(BaseTree)?itr.next(); ??

????????????????stack.push(btchild); ??

????????????} ??

????????} ??

????????set.remove(this); ??

????????return?set; ??

????}???? ??

????abstract?public?Set?getChildren(); ??

????public?void?addObject(Object?obj)?{ ??

????????objects.add(obj); ??

????} ??

????public?void?rmObject(Object?obj)?{ ??

????????objects.remove(obj); ??

????} ??

????abstract?public?Set?getObjects(); ??

????public?void?setParent(Tree?parent)?{ ??

????????this.parent?=?(BaseTree)?parent; ??

????} ??

????public?void?setChildren(Set?children)?{ ??

????????this.children?=?children; ??

????} ??

????public?void?setObjects(Set?objects)?{ ??

????????this.objects?=?objects; ??

????}???? ??

}??

package test.testtree.base; import java.util.*;public abstract class BaseTree extends BasePojo implements Tree{ protected String code; protected String name; protected String description; protected BaseTree parent; protected Set children = new HashSet(); protected Set objects = new HashSet(); public void setCode(String code) {this.code = code;} abstract public String getCode();public void setName(String name) {this.name = name;} abstract public String getName(); public void setDescription(String description) {this.description = description;}abstract public String getDescription();abstract public Tree getParent(); public boolean isRoot() {return (getParent()==null);} public boolean isLeaf() {return (this.getChildren().size()==0);} public boolean isParentOf(Tree tree) {if (tree==null || ((BaseTree) tree).equals(this)) {/*如果對方為空*/return false;}else if(this.isLeaf()){/*如果自己為葉子,則返回FALSE*/return false;}else if(tree.isRoot()){/*如果對方為根,返回FALSE*/return false;}else{BaseTree bt = (BaseTree) (tree.getParent());if (this.equals(bt)){/*如果對方的父節點是自己,則返回TRUE*/return true;}else{/*判斷對方的父節點是否是自己的孩子,進行遞歸*/return isParentOf(bt);}}}public boolean isChildOf(Tree tree) {return (tree.isParentOf(this));}public void addChild(Tree tree) {children.add(tree);}public void rmChild(Tree tree) {children.remove(tree);((BaseTree) tree).setParent(null);}public Set getAllLeaves() {Set set_old = this.getAllChildren();Set set = new HashSet();set.addAll(set_old);Iterator itr = set_old.iterator();while(itr.hasNext()){BaseTree bt = (BaseTree) itr.next();if (! bt.isLeaf()){set.remove(bt);}}return set;}public Set getParents(){Set parents = new HashSet(); Tree p = this.getParent();if(p!=null){parents.add(p);parents.addAll(p.getParents());}return parents;}public Set getAllChildren() {Set set = new HashSet();Stack stack = new Stack();stack.push(this);while(!stack.empty()){BaseTree bt = (BaseTree) stack.pop();set.add(bt);Iterator itr = bt.getChildren().iterator();while(itr.hasNext()){BaseTree btchild = (BaseTree) itr.next();stack.push(btchild);}}set.remove(this);return set;} abstract public Set getChildren();public void addObject(Object obj) {objects.add(obj);}public void rmObject(Object obj) {objects.remove(obj);}abstract public Set getObjects();public void setParent(Tree parent) {this.parent = (BaseTree) parent;}public void setChildren(Set children) {this.children = children;}public void setObjects(Set objects) {this.objects = objects;} }

?

• treetest.part1.rar (3.2 MB)
• 描述: part1
• 下載次數: 2635

• treetest.part2.rar (3 MB)
• 描述: part2
• 下載次數: 2255

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