CommonUtil.java

package cn.edu.njupt.allgo.service.utils;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.List;
import java.util.Map;

import javax.servlet.http.HttpServletResponse;

import net.sf.json.JSONArray;
import net.sf.json.JSONObject;
import net.sf.json.JsonConfig;
import net.sf.json.processors.JsDateJsonBeanProcessor;

import org.apache.commons.lang.StringUtils;

public class CommonUtil {
	// 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;

	// content-type 定义 //
	private static final String TEXT = "text/plain";
	private static final String JSON = "application/json";
	private static final String XML = "text/xml";
	private static final String HTML = "text/html";

	// 绕过jsp/freemaker直接输出文本的函串//

	/**
	 * 直接输出内容的简便函串kkkkkkk
	 * 
	 * 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:"串no-cache:",默认值分别为UTF-8和true.
	 */
	public static void render(final HttpServletResponse response, 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 + "不是串��合法的header类型");
			}

			// 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);
			}

			PrintWriter writer = response.getWriter();
			writer.write(content);
			response.getWriter().flush();
			writer.close();
		} catch (IOException e) {
			e.printStackTrace();
		}
	}

	/**
	 * 直接输出文本.
	 * 
	 * @see #render(String, String, String...)
	 */
	public static void renderText(final HttpServletResponse response, final String text, final String... headers) {
		render(response, TEXT, text, headers);
	}

	/**
	 * 直接输出HTML.
	 * 
	 * @see #render(String, String, String...)
	 */
	public static void renderHtml(final HttpServletResponse response, final String html, final String... headers) {
		render(response, HTML, html, headers);
	}

	/**
	 * 直接输出XML.
	 * 
	 * @see #render(String, String, String...)
	 */
	public static void renderXml(final HttpServletResponse response, final String xml, final String... headers) {
		render(response, XML, xml, headers);
	}

	/**
	 * 直接输出JSON.
	 * 
	 * @param string
	 *            json字符串
	 * @see #render(String, String, String...)
	 */
	public static void renderJson(final HttpServletResponse response, final String jsonString, final String... headers) {
		render(response, JSON, jsonString, 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...)
	 */
	public static void renderJson(final HttpServletResponse response, @SuppressWarnings("rawtypes") final Map map,
			final String... headers) {
		String jsonString = JSONObject.fromObject(map).toString();
		render(response, JSON, 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 HttpServletResponse response, final Object object, final String... headers) {
		String jsonString = JSONObject.fromObject(object).toString();
		render(response, JSON, jsonString, headers);
	}

	/**
	 * 直接输出JSON.
	 * 
	 * @param response
	 * @param list
	 * @param headers
	 */
	public static void renderJson(final HttpServletResponse response, final List<?> list, final String... headers) {
		String jsonString = JSONArray.fromObject(list).toString();
		render(response, JSON, jsonString, headers);
	}

	/**
	 * 直接输出JSON.含有java.sql.date数据类型
	 * 
	 * @param response
	 * @param object
	 * @param headers
	 */
	public static void renderJsonForSqlDate(final HttpServletResponse response, final Object object,
			final String... headers) {
		JsDateJsonBeanProcessor beanProcessor = new JsDateJsonBeanProcessor();
		JsonConfig config = new JsonConfig();
		config.registerJsonBeanProcessor(java.sql.Date.class, beanProcessor);
		JSONObject json = JSONObject.fromObject(object, config);
		render(response, JSON, json.toString(), headers);
	}

	public static void main(String args[]) {

	}

	/**
	 * 直接输出内容与转串
	 * 
	 * @param rep
	 * @param message
	 * @param URL
	 * @param headers
	 */
	public static void renderScript(final HttpServletResponse rep, final String message, final String... headers) {
		PrintWriter printer = null;
		try {
			rep.setContentType("text/html;charset=UTF-8");
			printer = rep.getWriter();
			printer.write("<script language = 'javascript'>");
			printer.write("alert('" + message + "'),");
			printer.write("window.history.go(-1)");
			printer.write("</script>");
		} catch (IOException e) {
			System.err.println(e.getLocalizedMessage());
		} finally {
			if (printer != null) {
				printer.close();
			}
		}
	}

	/**
	 * json To List<?>
	 * 
	 * @param jsonStr
	 * @param objClass
	 * @return
	 */
	@SuppressWarnings("deprecation")
	public static List<?> toList(final String jsonStr, Class<?> objClass) {
		JSONArray jsArray = JSONArray.fromObject(jsonStr);
		List<?> list = JSONArray.toList(jsArray, objClass);
		return list;
	}

	/**
	 * json to object
	 * 
	 * @param jsonStr
	 * @param objClass
	 * @return
	 */
	public static Object toObject(final String jsonStr, Class<?> objClass) {
		JSONObject jsObject = JSONObject.fromObject(jsonStr);
		return JSONObject.toBean(jsObject, objClass);
	}
}