JAVA 非常实用的servlet工具类

import java.io.UnsupportedEncodingException;import java.util.Enumeration;import java.util.Map;import java.util.StringTokenizer;import java.util.TreeMap;import javax.servlet.ServletRequest;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;/*** Http与Servlet工具类.*/public abstract class ServletUtils {//-- Content Type 定义 --//public static final String EXCEL_TYPE = "application/vnd.ms-excel";public static final String HTML_TYPE = "text/html";public static final String JS_TYPE = "text/javascript";public static final String JSON_TYPE = "application/json";public static final String XML_TYPE = "text/xml";public static final String TEXT_TYPE = "text/plain";//-- Header 定义 --//public static final String AUTHENTICATION_HEADER = "Authorization";//-- 常用数值定义 --//public static final long ONE_YEAR_SECONDS = 60 * 60 * 24 * 365;/*** 设置客户端缓存过期时间 的Header.*/public static void setExpiresHeader(HttpServletResponse response, long expiresSeconds) {//Http 1.0 headerresponse.setDateHeader("Expires", System.currentTimeMillis() + expiresSeconds * 1000);//Http 1.1 headerresponse.setHeader("Cache-Control", "private, max-age=" + expiresSeconds);}/*** 设置禁止客户端缓存的Header.*/public static void setDisableCacheHeader(HttpServletResponse response) {//Http 1.0 headerresponse.setDateHeader("Expires", 1L);response.addHeader("Pragma", "no-cache");//Http 1.1 headerresponse.setHeader("Cache-Control", "no-cache, no-store, max-age=0");}/*** 设置LastModified Header.*/public static void setLastModifiedHeader(HttpServletResponse response, long lastModifiedDate) {response.setDateHeader("Last-Modified", lastModifiedDate);}/*** 设置Etag Header.*/public static void setEtag(HttpServletResponse response, String etag) {response.setHeader("ETag", etag);}/*** 根据浏览器If-Modified-Since Header, 计算文件是否已被修改.** 如果无修改, checkIfModify返回false ,设置304 not modify status.** @param lastModified 内容的最后修改时间.*/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;}/*** 根据浏览器 If-None-Match Header, 计算Etag是否已无效.** 如果Etag有效, checkIfNoneMatch返回false, 设置304 not modify status.** @param etag 内容的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;}/*** 设置让浏览器弹出下载对话框的Header.** @param fileName 下载后的文件名.*/public static void setFileDownloadHeader(HttpServletResponse response, String fileName) {try {//中文文件名支持String encodedfileName = new String(fileName.getBytes(), "ISO8859-1");response.setHeader("Content-Disposition", "attachment; filename=\"" + encodedfileName + "\"");} catch (UnsupportedEncodingException e) {}}/*** 取得带相同前缀的Request Parameters.* 返回的结果的Parameter名已去除前缀.*/public static Map<String, Object> getParametersStartingWith(ServletRequest request, String prefix) {AssertUtils.notNull(request, "Request must not be null");Enumeration paramNames = request.getParameterNames();Map<String, Object> params = new TreeMap<String, Object>();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) {// Do nothing, no values found at all.} else if (values.length > 1) {params.put(unprefixed, values);} else {params.put(unprefixed, values[0]);}}}return params;}/*** 对Http Basic验证的 Header进行编码.*/public static String encodeHttpBasic(String userName, String password) {String encode = userName + ":" + password;return "Basic " + EncodeUtils.base64Encode(encode.getBytes());}}