ajax4jsf afterphase,自定义开发具有Ajax功能的JSF组件

package com.sterning.jsf.ajax;

import javax.faces.component.UIComponent;

import javax.faces.context.FacesContext;

public interface AjaxRendererInterface {

public void handleAjaxRequest(FacesContext context, UIComponent component);

}

2．实现接口并继承Renderer类

com.sterning.jsf.ajax.component. AjaxComponentRenderer类

package com.sterning.jsf.ajax.component;

import java.io.IOException;

import javax.faces.component.UIComponent;

import javax.faces.context.FacesContext;

import javax.faces.context.ResponseWriter;

import javax.faces.render.Renderer;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import org.apache.commons.logging.*;

import com.sterning.jsf.ajax.AjaxRendererInterface;

public class AjaxComponentRenderer extends Renderer implements

AjaxRendererInterface {

private static final transient Log log = LogFactory

.getLog(com.sterning.jsf.ajax.component.AjaxComponentRenderer.class);

private static final String INPUT_ID = "com.sterning.jsf.ajax.component.INPUT";

private static final String INPUT_NAME = "com.sterning.jsf.ajax.component.INPUT";

private static final String BUTTON_ID = "com.sterning.jsf.ajax.component.BUTTON";

private static final String MESSAGE_DIV_ID = "com.sterning.jsf.ajax.component.MESSAGE_DIV";

private static final String CLIENT_ID = "com.sterning.jsf.ajax.component.CLIENT_ID";

/** *//**

* 定义渲染器。渲染器我们需要从Renderer类中继承，不过我们一般情况下会继承HtmlRenderer这个类，我们可以覆盖decode

* encodeBegin encodeChildren encodeEnd 来生成HTML

*/

public AjaxComponentRenderer() {

}

public void encodeBegin(FacesContext context, UIComponent component)

throws IOException {

if (log.isTraceEnabled()) {

log.trace("begin encodeBegin()");

}

HttpServletRequest request = (HttpServletRequest) context

.getExternalContext().getRequest();

AjaxComponent ajaxComp = (AjaxComponent) component;

ResponseWriter out = context.getResponseWriter();

String clientId = ajaxComp.getClientId(context);

out.startElement("div", ajaxComp);

out.writeAttribute("id", clientId, null);

out.writeAttribute("style", "border:solid; width:200; height:200;",

null);

out.startElement("div", ajaxComp); // Message div

out.writeAttribute("id", MESSAGE_DIV_ID, null);

out.endElement("div"); // Message div

out.startElement("input", ajaxComp);

out.writeAttribute("type", "text", null);

out.writeAttribute("id", INPUT_ID, null);

out.writeAttribute("name", INPUT_NAME, null);

out.endElement("input");

out.startElement("button", component);

out.writeAttribute("type", "button", null);

out.writeAttribute("name", BUTTON_ID, null);

out.writeAttribute("id", BUTTON_ID, null);

out.writeAttribute("value", BUTTON_ID, null);

out.writeText("Ajax It", "null");

out.endElement("button");

// A hidden field to hold the URL of the server for the ajax request

out.startElement("input", ajaxComp);

out.writeAttribute("id", "com.sterning.jsf.ajax.component.SERVER", null);

out.writeAttribute("type", "hidden", null);

out.writeAttribute("value", request.getScheme() + "://"

+ request.getServerName() + ":" + request.getServerPort()

+ request.getRequestURI(), null);

out.endElement("input");

// A hidden field to hold the component Client ID

out.startElement("input", ajaxComp);

out.writeAttribute("id", CLIENT_ID, null);

out.writeAttribute("type", "hidden", null);

out.writeAttribute("value", clientId, null);

out.endElement("input");

out.write("\nAjax组件\n");

out.startElement("script", ajaxComp);

out.write("dojo.addOnLoad(AjaxComponent.loadComponent());\n");

out.endElement("script");

}

/** *//**

* 处理页面按钮的请求, 该项按钮通过上面的encodeBegin()方法设置

*/

public void handleAjaxRequest(FacesContext context, UIComponent component) {

if (log.isInfoEnabled()) {

log.info("BEGIN handleAjaxRequest()");

}

HttpServletRequest request = (HttpServletRequest) context

.getExternalContext().getRequest();

String textField = request.getParameter(INPUT_NAME);

String serverContribution = "SERVER RESPONSE: ";

StringBuffer xml = null;

if (textField == null) {

if (log.isInfoEnabled()) {

log.info("No parameter found for text field.");

}

} else {

if (log.isTraceEnabled()) {

log.trace("textField: " + textField);

}

xml = new StringBuffer("");

xml.append("" + serverContribution + textField

+ "");

xml.append("OK");

}

if (xml == null) {

if (log.isInfoEnabled()) {

log.info("Response is null.");

}

xml = new StringBuffer(this.getErrorString());

}

HttpServletResponse response = (HttpServletResponse) context

.getExternalContext().getResponse();

response.setContentType("text/xml");

response.setHeader("Cache-Control", "no-cache");

try {

response.getWriter().write(xml.toString());

if (log.isInfoEnabled()) {

log.info("Response sent: " + xml);

}

} catch (IOException e) {

if (log.isErrorEnabled()) {

log.error("Error writing ajax response.", e);

}

}

}

protected String getErrorString() {

return new String(

"There was a problemERROR");

}

}