com.baoqilai.core.util.WebUtils.java Source code

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Here is the source code for com.baoqilai.core.util.WebUtils.java

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/**
 * Copyright (c) 2005-2010 springside.org.cn
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * 
 * $Id: Struts2Utils.java 1211 2010-09-10 16:20:45Z calvinxiu $
 */
package com.baoqilai.core.util;

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 org.slf4j.Logger;

/**
 * Web.
 * 
 * ?Request/Response/Sessionjsp/freemaker.
 * 
 * @author calvin
 */
public final class WebUtils {

    // -- 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;

    // -- Content Type  --//
    public static final String TEXT_TYPE = "text/plain";
    public static final String JSON_TYPE = "application/json";
    public static final String XML_TYPE = "text/xml";
    public static final String HTML_TYPE = "text/html";
    public static final String JS_TYPE = "text/javascript";
    public static final String EXCEL_TYPE = "application/vnd.ms-excel";

    private static ObjectMapper mapper = new ObjectMapper();

    private static Logger logger = LoggerUtils.getLogger(WebUtils.class);

    private WebUtils() {

    }

    // -- ?Request/Response/Session --//
    /**
     * ?HttpSession.
     */
    public static HttpSession getSession() {
        return ServletActionContext.getRequest().getSession();
    }

    /**
     * ?HttpSession.
     */
    public static HttpSession getSession(boolean isNew) {
        return ServletActionContext.getRequest().getSession(isNew);
    }

    /**
     * ?HttpSessionAttribute.
     */
    public static Object getSessionAttribute(String name) {
        HttpSession session = getSession(false);
        return (session != null ? session.getAttribute(name) : null);
    }

    /**
     * ?web?
     * @param path 
     * @return
     */
    public static String getRealPath() {
        return getRealPath("");
    }

    public static String getRealPath(String path) {
        return ServletActionContext.getServletContext().getRealPath(path);
    }

    /**
     * ?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 (Exception e) {
            logger.warn(e.getMessage(), e);
        }
    }

    /**
     * .
     * 
     * @see #render(String, String, String...)
     */
    public static void renderText(final String text, final String... headers) {
        render(TEXT_TYPE, text, headers);
    }

    /**
     * HTML.
     * 
     * @see #render(String, String, String...)
     */
    public static void renderHtml(final String html, final String... headers) {
        render(HTML_TYPE, html, headers);
    }

    /**
     * XML.
     * 
     * @see #render(String, String, String...)
     */
    public static void renderXml(final String xml, final String... headers) {
        render(XML_TYPE, xml, headers);
    }

    /**
     * JSON.
     * 
     * @param jsonString
     *            json.
     * @see #render(String, String, String...)
     */
    public static void renderJson(final String jsonString, final String... headers) {
        render(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(JSON_TYPE, headers);
        try {
            mapper.writeValue(response.getWriter(), data);
        } catch (Exception e) {
            logger.warn(e.getMessage(), 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 = mapper.writeValueAsString(object);
        } catch (Exception e) {
            logger.warn(e.getMessage(), e);
        }

        String result = new StringBuilder().append(callbackName).append("(").append(jsonString).append(");")
                .toString();

        // Content-Typejavascript,javascript?, callback197("{html:'Hello World!!!'}");
        render(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 = ServletActionContext.getResponse();

        // headers?
        String fullContentType = contentType + ";charset=" + encoding;
        response.setContentType(fullContentType);
        if (noCache) {
            setDisableCacheHeader(response);
        }

        return response;
    }

    /**
     * ?Header.
     */
    public static void setDisableCacheHeader(HttpServletResponse response) {
        // Http 1.0 header
        response.setDateHeader("Expires", 1L);
        response.addHeader("Pragma", "no-cache");
        // Http 1.1 header
        response.setHeader("Cache-Control", "no-cache, no-store, max-age=0");
    }

}