Java tutorial
package com.lll.util; /** * Copyright (c) 2005-2009 springside.org.cn * * Licensed under the Apache License, Version 2.0 (the "License"); * * $Id: ServletUtils.java 1048 2010-04-17 11:23:09Z calvinxiu $ */ import java.io.IOException; import java.io.UnsupportedEncodingException; import java.util.Enumeration; import java.util.Map; import java.util.StringTokenizer; import java.util.TreeMap; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import org.apache.commons.lang.StringUtils; import org.codehaus.jackson.map.ObjectMapper; import org.codehaus.jackson.map.SerializationConfig.Feature; /** * HttpServlet. * */ public class ServletUtils { //-- 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"; //-- Header --// public static final String AUTHENTICATION_HEADER = "Authorization"; //-- --// public static final long ONE_YEAR_SECONDS = 60 * 60 * 24 * 365; //-- 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 = new ObjectMapper(); /** * Header. */ public static void setExpiresHeader(HttpServletResponse response, long expiresSeconds) { //Http 1.0 header response.setDateHeader("Expires", System.currentTimeMillis() + expiresSeconds * 1000); //Http 1.1 header response.setHeader("Cache-Control", "private, max-age=" + expiresSeconds); } /** * Header. */ public static void setNoCacheHeader(HttpServletResponse response) { //Http 1.0 header response.setDateHeader("Expires", 0); response.addHeader("Pragma", "no-cache"); //Http 1.1 header response.setHeader("Cache-Control", "no-cache"); } /** * LastModified Header. */ public static void setLastModifiedHeader(HttpServletResponse response, long lastModifiedDate) { response.setDateHeader("Last-Modified", lastModifiedDate); } /** * Etag Header. */ public static void setEtag(HttpServletResponse response, String etag) { response.setHeader("ETag", etag); } /** * ??If-Modified-Since Header, ?. * * , checkIfModifyfalse ,304 not modify status. * * @param lastModified ?. */ public static boolean checkIfModifiedSince(HttpServletRequest request, HttpServletResponse response, long lastModified) { long ifModifiedSince = request.getDateHeader("If-Modified-Since"); if ((ifModifiedSince != -1) && (lastModified < ifModifiedSince + 1000)) { response.setStatus(HttpServletResponse.SC_NOT_MODIFIED); return false; } return true; } /** * ?? If-None-Match Header, Etag?. * * Etag, checkIfNoneMatchfalse, 304 not modify status. * * @param etag ETag. */ public static boolean checkIfNoneMatchEtag(HttpServletRequest request, HttpServletResponse response, String etag) { String headerValue = request.getHeader("If-None-Match"); if (headerValue != null) { boolean conditionSatisfied = false; if (!"*".equals(headerValue)) { StringTokenizer commaTokenizer = new StringTokenizer(headerValue, ","); while (!conditionSatisfied && commaTokenizer.hasMoreTokens()) { String currentToken = commaTokenizer.nextToken(); if (currentToken.trim().equals(etag)) { conditionSatisfied = true; } } } else { conditionSatisfied = true; } if (conditionSatisfied) { response.setStatus(HttpServletResponse.SC_NOT_MODIFIED); response.setHeader("ETag", etag); return false; } } return true; } /** * ??Header. * * @param fileName ???. */ public static void setFileDownloadHeader(HttpServletResponse response, String fileName) { try { //??? String encodedfileName = new String(fileName.getBytes(), "ISO8859-1"); response.setHeader("Content-Disposition", "attachment; filename=\"" + encodedfileName + "\""); } catch (UnsupportedEncodingException e) { } } /** * ???Request Parameters. * * Parameter???. */ @SuppressWarnings({ "unchecked", "rawtypes" }) public static Map getParametersStartingWith(HttpServletRequest request, String prefix) { Enumeration paramNames = request.getParameterNames(); Map params = new TreeMap(); if (prefix == null) { prefix = ""; } while (paramNames != null && paramNames.hasMoreElements()) { String paramName = (String) paramNames.nextElement(); if ("".equals(prefix) || paramName.startsWith(prefix)) { String unprefixed = paramName.substring(prefix.length()); String[] values = request.getParameterValues(paramName); if (values == null || values.length == 0) {//NOSONAR // Do nothing, no values found at all. } else if (values.length > 1) { params.put(unprefixed, (Object) values); } else { params.put(unprefixed, values[0]); } } } return params; } /** * Http Basic? Header?. */ public static String encodeHttpBasic(String userName, String password) { String encode = userName + ":" + password; return "Basic " + EncodeUtils.base64Encode(encode.getBytes()); } //-- 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(HttpServletResponse response, final String contentType, final String content, final String... headers) { initResponseHeader(response, contentType, 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(HttpServletResponse response, final String text, final String... headers) { render(response, ServletUtils.TEXT_TYPE, text, headers); } /** * HTML. * @see #render(String, String, String...) */ public static void renderHtml(HttpServletResponse response, final String html, final String... headers) { render(response, ServletUtils.HTML_TYPE, html, headers); } /** * XML. * @see #render(String, String, String...) */ public static void renderXml(HttpServletResponse response, final String xml, final String... headers) { render(response, ServletUtils.XML_TYPE, xml, headers); } /** * JSON. * * @param jsonString json. * @see #render(String, String, String...) */ public static void renderJson(HttpServletResponse response, final String jsonString, final String... headers) { render(response, ServletUtils.JSON_TYPE, jsonString, headers); } /** * JSON,Jackson?Java. * * @param data ?List<POJO>, POJO[], POJO, ?Map??. * @see #render(String, String, String...) */ public static void renderJson(HttpServletResponse response, final Object data, final String... headers) { initResponseHeader(response, ServletUtils.JSON_TYPE, headers); try { mapper.getSerializationConfig().set(Feature.FAIL_ON_EMPTY_BEANS, false); mapper.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(HttpServletResponse response, final String callbackName, final Object object, final String... headers) { String jsonString = null; try { jsonString = mapper.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(response, ServletUtils.JS_TYPE, result, headers); } /** * ?contentTypeheaders. */ private static void initResponseHeader(HttpServletResponse response, 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"); } } //headers? String fullContentType = contentType + ";charset=" + encoding; response.setContentType(fullContentType); if (noCache) { ServletUtils.setNoCacheHeader(response); } } }