RichFaces树组件的用法
原创：版权所有chszs
RichFaces Tree组件提供了一个缺省的数据模型，允许显示简单的树结构，无需创建自己的树模型类集。
下面的例子说明了从属性文件的数据生成树目录。
选择左边树组件的节点，右边会显示出相应的节点名。如图所示：
如上图所示，建立图示页面的步骤如下：
一、搭建RichFaces开发环境，这一步省略；
二、编辑页面：
<ui:composition xmlns="http://www.w3.org/1999/xhtml" xmlns:ui="http://java.sun.com/jsf/facelets" xmlns:h="http://java.sun.com/jsf/html" xmlns:f="http://java.sun.com/jsf/core" xmlns:rich="http://richfaces.org/rich" xmlns:a4j="http://richfaces.org/a4j"> <mce:style><!-- .col,.col2 { width: 50%; vertical-align: top; } --></mce:style><style mce_bogus="1">.col,.col2 { width: 50%; vertical-align: top; }</style> <h:form> <fieldset> <legend>Directory Tree</legend> <h:panelGrid columns="2" width="100%" columnClasses="col1,col2"> <rich:tree style="width:150px;" nodeSelectListener="#{simpleTreeBean.processSelection}" reRender="selectedNode" ajaxSubmitSelection="true" switchType="client" value="#{simpleTreeBean.treeNode}" var="item"> </rich:tree> <h:outputText escape="false" value="Selected Node:#{simpleTreeBean.nodeTitle}" id="selectedNode" /> </h:panelGrid> </fieldset> </h:form> </ui:composition>
页面文件需说明两点：
1）<rich:tree>组件的ajaxSubmitSelection属性，为真时表示支持Ajax提交；
2）<rich:tree>组件的value属性，其值是org.richfaces.model.TreeNode类的实例。
三、属性文件：
1=/u7CFB/u7EDF/u7BA1/u7406 1.1=/u6743/u9650/u5206/u914D 1.2=/u89D2/u8272/u7BA1/u7406 1.3=/u5BC6/u7801/u4FEE/u6539 1.4=/u5BC6/u7801/u7B56/u7565 1.5=/u7CFB/u7EDF/u65E5/u5FD7 1.5.1=/u7528/u6237/u65E5/u5FD7 1.5.2=/u64CD/u4F5C/u8BB0/u5F55 2=/u8BBE/u5907/u7BA1/u7406 2.1=DVB-2 2.2=DTV-4 3=/u5458/u5DE5/u7BA1/u7406 3.1=/u5458/u5DE5/u4FE1/u606F 3.2=/u8BF7/u5047/u60C5/u51B5
转码后的文字如图所示：
四、托管Bean文件
package chcms.view.mbeans; import org.richfaces.component.html.HtmlTree; import org.richfaces.event.NodeSelectedEvent; import org.richfaces.model.TreeNode; import org.richfaces.model.TreeNodeImpl; import java.io.IOException; import java.io.InputStream; import java.util.*; import javax.faces.FacesException; import javax.faces.context.ExternalContext; import javax.faces.context.FacesContext; public class SimpleTreeBean { private TreeNode rootNode = null; private List<String> selectedNodeChildren = new ArrayList<String>(); private String nodeTitle; private static final String DATA_PATH="/test/simple-tree-data.properties"; public TreeNode getTreeNode(){ if(rootNode == null){ loadTree(); } return rootNode; } public String getNodeTitle(){ return nodeTitle; } public void setNodeTitle(String nodeTitle){ this.nodeTitle = nodeTitle; } private void addNodes(String path, TreeNode node, Properties properties){ boolean end = false; int counter = 1; while(!end){ String key = path != null ? path+'.'+counter:String.valueOf(counter); String value = properties.getProperty(key); if(value!=null){ TreeNodeImpl nodeImpl = new TreeNodeImpl(); nodeImpl.setData(value); node.addChild(new Integer(counter), nodeImpl); addNodes(key, nodeImpl, properties); counter++; }else{ end = true; } } } private void loadTree(){ FacesContext facesContext = FacesContext.getCurrentInstance(); ExternalContext externalContext = facesContext.getExternalContext(); InputStream dataStream = externalContext.getResourceAsStream(DATA_PATH); try{ Properties properties = new Properties(); properties.load(dataStream); rootNode = new TreeNodeImpl(); addNodes(null, rootNode, properties); }catch(IOException e){ throw new FacesException(e.getMessage()); }finally{ if(dataStream!=null){ try{ dataStream.close(); }catch(IOException e){ externalContext.log(e.getMessage(), e); } } } } public void processSelection(NodeSelectedEvent event){ HtmlTree tree = (HtmlTree)event.getComponent(); nodeTitle = (String)tree.getRowData(); selectedNodeChildren.clear(); TreeNode currentNode = tree.getModelTreeNode(tree.getRowKey()); if(currentNode.isLeaf()){ selectedNodeChildren.add((String)currentNode.getData()); }else{ Iterator<Map.Entry<Object, TreeNode>> it = currentNode.getChildren(); while(it!=null && it.hasNext()){ Map.Entry<Object, TreeNode> entry = it.next(); selectedNodeChildren.add(entry.getValue().getData().toString()); } } } }
托管Bean需说明几点：
1）DATA_PATH表示属性文件的路径；
2）addNodes()方法采用了递归算法，需注意；
3）需理解java.util.Properties的用法；
4）理解构造树组件的缺省实现类org.richfaces.model.TreeNodeImpl类。
五、RichFaces配置文件：
<managed-bean> <managed-bean-name>simpleTreeBean</managed-bean-name> <managed-bean-class>chcms.view.mbeans.SimpleTreeBean</managed-bean-class> <managed-bean-scope>request</managed-bean-scope> </managed-bean>
以上内容能实现图示例子。一些次要步骤省略！
