CrudActionSupport.java

package com.norteksoft.product.web.struts2;

import java.io.IOException;

import javax.servlet.http.HttpServletResponse;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.struts2.ServletActionContext;

import com.opensymphony.xwork2.ActionSupport;
import com.opensymphony.xwork2.ModelDriven;
import com.opensymphony.xwork2.Preparable;

/**
 * Struts2中典型CRUD Action的抽象基类.
 * 
 * 主要定义了对Preparable,ModelDriven接口的使用,以及CRUD函数和返回值的命名.
 *
 * @param <T> CRUDAction所管理的对象类型.
 * 
 */
@SuppressWarnings("serial")
public abstract class CrudActionSupport<T> extends ActionSupport implements ModelDriven<T>, Preparable {

	/**
	 * 进行增删改操作后,以redirect方式重新打开action默认页的result名.
	 */
	public static final String RELOAD = "reload";

	private Log logger = LogFactory.getLog(getClass());

	// CRUD函数 //

	/**
	 * Action函数,新增或修改Entity. 
	 * 建议return RELOAD.
	 */
	public abstract String save() throws Exception;

	/**
	 * Action函数,删除Entity.
	 * 建议return RELOAD.
	 */
	public abstract String delete() throws Exception;

	/**
	 * Action函数, 默认的action函数, 默认调用list()函数.
	 */
	@Override
	public String execute() throws Exception {
		return list();
	}

	/**
	 * Action函数,显示Entity列表界面.
	 * 建议return SUCCESS.
	 */
	public abstract String list() throws Exception;

	/**
	 * Action函数,显示新增或修改Entity界面.
	 * 建议return INPUT.
	 */
	@Override
	public abstract String input() throws Exception;

	// Preparable函数 //

	/**
	 * 实现空的prepare()函数,屏蔽所有Action函数公共的二次绑定.
	 */
	public void prepare() throws Exception {
	}

	/**
	 * 在input()前执行二次绑定.
	 */
	public void prepareInput() throws Exception {
		prepareModel();
	}

	/**
	 * 在save()前执行二次绑定.
	 */
	public void prepareSave() throws Exception {
		prepareModel();
	}

	/**
	 * 等同于prepare()的内部函数,供prepardMethodName()函数调用. 
	 */
	protected abstract void prepareModel() throws Exception;
	
	/**
	 * 绕过Template,直接输出内容的简便函数. 
	 */
	protected String render(String text, String contentType) {
		try {
			HttpServletResponse response = ServletActionContext.getResponse();
			response.setContentType(contentType);
			response.getWriter().write(text);
		} catch (IOException e) {
			logger.error(e.getMessage(), e);
		}
		return null;
	}

	/**
	 * 直接输出字符串.
	 */
	protected String renderText(String text) {
		return render(text, "text/plain;charset=UTF-8");
	}

	/**
	 * 直接输出script,可以用于jsonp
	 * @param text
	 * @return
	 */
	protected String renderScript(String text){
		return render(text, "text/script;charset=UTF-8");
	}
	/**
	 * 直接输出HTML.
	 */
	protected String renderHtml(String html) {
		return render(html, "text/html;charset=UTF-8");
	}

	/**
	 * 直接输出XML.
	 */
	protected String renderXML(String xml) {
		return render(xml, "text/xml;charset=UTF-8");
	}
}