Java tutorial
/** * Copyright (c) 2005-2009 springside.org.cn * * Licensed under the Apache License, Version 2.0 (the "License"); * * $Id: Struts2Utils.java 1005 2010-03-25 15:50:00Z calvinxiu $ */ package com.dgq.utils; import java.io.IOException; import java.util.Map; import javax.servlet.ServletContext; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import javax.servlet.http.HttpSession; import org.apache.commons.lang.StringUtils; import org.apache.struts2.ServletActionContext; import org.codehaus.jackson.map.ObjectMapper; import com.dgq.utils.ServletUtils; import com.opensymphony.xwork2.ActionContext; /** * Struts2. * * ?Request/Response/Sessionjsp/freemaker. * * @author calvin */ public class Struts2Utils { // -- header ? --// private static final String HEADER_ENCODING = "encoding"; private static final String HEADER_NOCACHE = "no-cache"; private static final String DEFAULT_ENCODING = "UTF-8"; private static final boolean DEFAULT_NOCACHE = true; private static ObjectMapper mapper = null; public static synchronized ObjectMapper getObjectMapper() { if (mapper == null) { mapper = new ObjectMapper(); } return mapper; } /** * ?AppContext. */ public static ServletContext getAppContext() { return ServletActionContext.getServletContext(); } // -- ?Request/Response/Session --// /** * ?HttpSession. */ public static HttpSession getSession() { return getRequest().getSession(); } /** * ?HttpSession. */ public static HttpSession getSession(boolean isNew) { return getRequest().getSession(isNew); } /** * ?HttpSessionAttribute. */ public static Object getSessionAttribute(String name) { // HttpSession session = getSession(false); // return (session != null ? session.getAttribute(name) : null); Map<String, Object> session = ActionContext.getContext().getSession(); return (session != null ? session.get(name) : null); } /** * HttpSessionAttribute,session */ public static void setSessionAttribute(String name, Object obj) { Map<String, Object> session = ActionContext.getContext().getSession(); session.put(name, obj); } /** * ?HttpRequest. */ public static HttpServletRequest getRequest() { return ServletActionContext.getRequest(); } /** * ?HttpRequestParameter. */ public static String getParameter(String name) { return getRequest().getParameter(name); } /** * ?HttpResponse. */ public static HttpServletResponse getResponse() { return ServletActionContext.getResponse(); } // -- jsp/freemaker --// /** * . * * eg. render("text/plain", "hello", "encoding:GBK"); render("text/plain", * "hello", "no-cache:false"); render("text/plain", "hello", "encoding:GBK", * "no-cache:false"); * * @param headers * ??header??"encoding:""no-cache:",UTF-8true. */ public static void render(final String contentType, final String content, final String... headers) { HttpServletResponse response = initResponseHeader(contentType, headers); try { response.getWriter().write(content); response.getWriter().flush(); } catch (IOException e) { throw new RuntimeException(e.getMessage(), e); } } public static void renderServlet(final String contentType, final String content, HttpServletResponse response, final String... headers) { response = initResponseHeaderServlet(contentType, response, headers); try { response.getWriter().write(content); response.getWriter().flush(); } catch (IOException e) { throw new RuntimeException(e.getMessage(), e); } } /** * . * * @see #render(String, String, String...) */ public static void renderText(final String text, final String... headers) { render(ServletUtils.TEXT_TYPE, text, headers); } /** * HTML. * * @see #render(String, String, String...) */ public static void renderHtml(final String html, final String... headers) { render(ServletUtils.HTML_TYPE, html, headers); } /** * XML. * * @see #render(String, String, String...) */ public static void renderXml(final String xml, final String... headers) { render(ServletUtils.XML_TYPE, xml, headers); } public static void renderXmlServlet(final String xml, HttpServletResponse response, final String... headers) { renderServlet(ServletUtils.XML_TYPE, xml, response, headers); } /** * JSON. * * @param jsonString * json. * @see #render(String, String, String...) */ public static void renderJson(final String jsonString, final String... headers) { render(ServletUtils.JSON_TYPE, jsonString, headers); } /** * JSON,Jackson?Java. * * @param data * ?List<POJO>, POJO[], POJO, ?Map??. * @see #render(String, String, String...) */ public static void renderJson(final Object data, final String... headers) { HttpServletResponse response = initResponseHeader(ServletUtils.JSON_TYPE, headers); try { getObjectMapper().writeValue(response.getWriter(), data); } catch (IOException e) { throw new IllegalArgumentException(e); } } /** * ?MashupJSONP. * * @param callbackName * callback??. * @param object * Java,?List<POJO>, POJO[], POJO ,?Map??, json. */ public static void renderJsonp(final String callbackName, final Object object, final String... headers) { String jsonString = null; try { jsonString = getObjectMapper().writeValueAsString(object); } catch (IOException e) { throw new IllegalArgumentException(e); } String result = new StringBuilder().append(callbackName).append("(").append(jsonString).append(");") .toString(); // Content-Typejavascript,javascript?, // callback197("{html:'Hello World!!!'}"); render(ServletUtils.JS_TYPE, result, headers); } /** * ?contentTypeheaders. */ private static HttpServletResponse initResponseHeader(final String contentType, final String... headers) { // ?headers? String encoding = DEFAULT_ENCODING; boolean noCache = DEFAULT_NOCACHE; for (String header : headers) { String headerName = StringUtils.substringBefore(header, ":"); String headerValue = StringUtils.substringAfter(header, ":"); if (StringUtils.equalsIgnoreCase(headerName, HEADER_ENCODING)) { encoding = headerValue; } else if (StringUtils.equalsIgnoreCase(headerName, HEADER_NOCACHE)) { noCache = Boolean.parseBoolean(headerValue); } else { throw new IllegalArgumentException(headerName + "??header"); } } HttpServletResponse response = getResponse(); // headers? String fullContentType = contentType + ";charset=" + encoding; response.setContentType(fullContentType); if (noCache) { ServletUtils.setNoCacheHeader(response); } return response; } private static HttpServletResponse initResponseHeaderServlet(final String contentType, HttpServletResponse response, final String... headers) { // ?headers? String encoding = DEFAULT_ENCODING; boolean noCache = DEFAULT_NOCACHE; for (String header : headers) { String headerName = StringUtils.substringBefore(header, ":"); String headerValue = StringUtils.substringAfter(header, ":"); if (StringUtils.equalsIgnoreCase(headerName, HEADER_ENCODING)) { encoding = headerValue; } else if (StringUtils.equalsIgnoreCase(headerName, HEADER_NOCACHE)) { noCache = Boolean.parseBoolean(headerValue); } else { throw new IllegalArgumentException(headerName + "??header"); } } // headers? String fullContentType = contentType + ";charset=" + encoding; response.setContentType(fullContentType); if (noCache) { ServletUtils.setNoCacheHeader(response); } return response; } }