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！
