org.nutz.mvc.view.AbstractPathView Maven / Gradle / Ivy

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Nutz, which is a collections of lightweight frameworks, each of them can be used independently
There is a newer version: 1.r.72
package org.nutz.mvc.view;

import java.util.Enumeration;
import java.util.HashMap;
import java.util.Map;
import java.util.Map.Entry;

import javax.servlet.http.HttpServletRequest;

import org.nutz.el.El;
import org.nutz.lang.Lang;
import org.nutz.lang.Strings;
import org.nutz.lang.segment.CharSegment;
import org.nutz.lang.segment.Segment;
import org.nutz.lang.util.Context;
import org.nutz.mvc.Loading;
import org.nutz.mvc.Mvcs;
import org.nutz.mvc.View;
import org.nutz.mvc.config.AtMap;
import org.nutz.mvc.impl.processor.ViewProcessor;

/**
 * @author mawm([email protected])
 * @author wendal([email protected])
 */
public abstract class AbstractPathView implements View {

	private Segment dest;

	private Map exps;

	public AbstractPathView(String dest) {
		if (null != dest) {
			this.dest = new CharSegment(Strings.trim(dest));
			this.exps = new HashMap();
			// 预先将每个占位符解析成表达式
			for (String key : this.dest.keys()) {
				this.exps.put(key, new El(key));
			}
		}
	}

	protected String evalPath(HttpServletRequest req, Object obj) {
		if (null == dest)
			return null;

		Context context = Lang.context();

		// 解析每个表达式
		Context expContext = createContext(req, obj);
		for (Entry en : exps.entrySet())
			context.set(en.getKey(), en.getValue().eval(expContext));

		// 生成解析后的路径
		return Strings.trim(this.dest.render(context).toString());
	}

	/**
	 * 为一次 HTTP 请求，创建一个可以被表达式引擎接受的上下文对象
	 * 
	 * @param req
	 *            HTTP 请求对象
	 * @param obj
	 *            入口函数的返回值
	 * @return 上下文对象
	 */
	@SuppressWarnings("unchecked")
	public static Context createContext(HttpServletRequest req, Object obj) {
		Context context = Lang.context();
		// 复制全局的上下文对象
		Object globalContext = Mvcs.getServletContext()
									.getAttribute(Loading.CONTEXT_NAME);
		if (globalContext != null) {
			context.putAll((Context) globalContext);
		}

		// 请求对象的属性列表
		Map req_attr = new HashMap();
		for (Enumeration en = req.getAttributeNames(); en.hasMoreElements();) {
			String tem = en.nextElement();
			req_attr.put(tem, req.getAttribute(tem));
		}
		context.set("a", req_attr);//兼容最初的写法
		context.set("req_attr", req_attr);
		
		Map session_attr = new HashMap();
		for (Enumeration en = req.getSession().getAttributeNames(); en.hasMoreElements();) {
			String tem = en.nextElement();
			session_attr.put(tem, req.getAttribute(tem));
		}
		context.set("session_attr", session_attr);
		
		
		// 请求的参数表,需要兼容之前的p.参数, Fix issue 418
		Map p = new HashMap();
		for (Object o : req.getParameterMap().keySet()) {
			String key = (String) o;
			String value = req.getParameter(key);
			p.put(key, value);
			context.set(key, value);//以支持直接获取请求参数
		}
		context.set("p", p);
		
		Map u = new HashMap();
		AtMap at = Mvcs.getAtMap();
		if (at != null) {
			for(Object o : at.keys()){
				String key = (String) o;
				u.put(key, at.get(key));
			}
			context.set("u", u);
		}
		
		// 加入返回对象
		if (null != obj)
			context.set(ViewProcessor.DEFAULT_ATTRIBUTE, obj);
		return context;
	}
}