Struts2工具类[实现获取Request/Response/Session与绕过jsp/freemaker直接输出文本的简化函数]

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package org.eline.web.struts2;
import java.io.IOException;
import java.util.Map;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import net.sf.json.JSONObject;
import org.apache.commons.lang.StringUtils;
import org.apache.struts2.ServletActionContext;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* Struts2 Utils类.
* 实现获取Request/Response/Session与绕过jsp/freemaker直接输出文本的简化函数.
*/
public class Struts2Utils
{
// header 常量定义
private static final String ENCODING_PREFIX = "encoding:";
private static final String NOCACHE_PREFIX = "no-cache:";
private static final String ENCODING_DEFAULT = "UTF-8";
private static final boolean NOCACHE_DEFAULT = true;
private static Logger logger = LoggerFactory.getLogger(Struts2Utils.class);
private Struts2Utils()
{
}
// 取得Request/Response/Session的简化函数 //
/**
* 取得HttpSession的简化方法.
*/
public static HttpSession getSession()
{
return ServletActionContext.getRequest().getSession();
}
/**
* 取得HttpRequest的简化方法.
*/
public static HttpServletRequest getRequest()
{
return ServletActionContext.getRequest();
}
/**
* 取得HttpResponse的简化方法.
*/
public static HttpServletResponse getResponse()
{
return ServletActionContext.getResponse();
}
// 绕过jsp/freemaker直接输出文本的函数 //
/**
* 直接输出内容的简便函数.
*
* 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
* 可变的header数组，目前接受的值为"encoding:"或"no-cache:",见示例代码.
* 不设置时默认值分别为UTF-8和true.
*/
public static void render(final String contentType, final String content,
final String... headers)
{
try
{
// 分析headers参数
String encoding = ENCODING_DEFAULT;
boolean noCache = NOCACHE_DEFAULT;
for (String header : headers)
{
String headerName = StringUtils.substringBefore(header, ":");
String headerValue = StringUtils.substringAfter(header, ":");
if (StringUtils.equalsIgnoreCase(headerName, ENCODING_PREFIX))
{
encoding = headerValue;
}
else if (StringUtils.equalsIgnoreCase(headerName,
NOCACHE_PREFIX))
{
noCache = Boolean.parseBoolean(headerValue);
}
else
throw new IllegalArgumentException(headerName
+ "不是一个合法的header类型");
}
HttpServletResponse response = ServletActionContext.getResponse();
// 设置headers参数
String fullContentType = contentType + ";charset=" + encoding;
response.setContentType(fullContentType);
if (noCache)
{
response.setHeader("Pragma", "No-cache");
response.setHeader("Cache-Control", "no-cache");
response.setDateHeader("Expires", 0);
}
response.getWriter().write(content);
}
catch (IOException e)
{
logger.error(e.getMessage(), e);
}
}
/**
* 直接输出文本.
*
* @see #render(String, String, String...)
*/
public static void renderText(final String text, final String... headers)
{
render("text/plain", text, headers);
}
/**
* 直接输出HTML.
*
* @see #render(String, String, String...)
*/
public static void renderHtml(final String html, final String... headers)
{
render("text/html", html, headers);
}
/**
* 直接输出XML.
*
* @see #render(String, String, String...)
*/
public static void renderXml(final String xml, final String... headers)
{
render("text/xml", xml, headers);
}
/**
* 直接输出JSON.
*
* @param string
* json字符串.
* @see #render(String, String, String...)
*/
public static void renderJson(final String string, final String... headers)
{
render("application/json", string, headers);
}
/**
* 直接输出JSON.???/
*
* @param map
* Map对象,将被转化为json字符串.
* @see #render(String, String, String...)
*/
@SuppressWarnings("unchecked")
public static void renderJson(final Map map, final String... headers)
{
String jsonString = new JSONObject().toString();
renderJson(jsonString, headers);
}
/**
* 直接输出JSON.???
*
* @param object
* Java对象,将被转化为json字符串.
* @see #render(String, String, String...)
*/
public static void renderJson(final Object object, final String... headers)
{
String jsonString = new JSONObject().toString();
renderJson(jsonString, headers);
}
}