Spring最近换域名了,去转转,发现了一个有意思的项目:spring mobile。
http://projects.spring.io/spring-mobile/
这个项目有很多实用的功能,如识别访问我们网站的设备是什么类型的(手机,平板,PC),据域名或者url来切换不同访问内容,据不同的访问设备转到不同的view中。
识别访问设备类型的核心代码在org.springframework.mobile.device.LiteDeviceResolver 类中,这个类实际上根据http请求头部的User-Agent的内容来判断设备到底是哪种类型的。
可以看到,这个类实际上是很简单的。不过字符串的匹配算法可能可以优化下。
[java] view
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- public class LiteDeviceResolver implements DeviceResolver {
- private final List<String> mobileUserAgentPrefixes = new ArrayList<String>();
- private final List<String> mobileUserAgentKeywords = new ArrayList<String>();
- private final List<String> tabletUserAgentKeywords = new ArrayList<String>();
- private final List<String> normalUserAgentKeywords = new ArrayList<String>();
- public LiteDeviceResolver() {
- init();
- }
- public LiteDeviceResolver(List<String> normalUserAgentKeywords) {
- init();
- this.normalUserAgentKeywords.addAll(normalUserAgentKeywords);
- }
- public Device resolveDevice(HttpServletRequest request) {
- String userAgent = request.getHeader("User-Agent");
- // UserAgent keyword detection of Normal devices
- if (userAgent != null) {
- userAgent = userAgent.toLowerCase();
- for (String keyword : normalUserAgentKeywords) {
- if (userAgent.contains(keyword)) {
- return resolveFallback(request);
- }
- }
- }
- // UAProf detection
- if (request.getHeader("x-wap-profile") != null || request.getHeader("Profile") != null) {
- return LiteDevice.MOBILE_INSTANCE;
- }
- // User-Agent prefix detection
- if (userAgent != null && userAgent.length() >= 4) {
- String prefix = userAgent.substring(0, 4).toLowerCase();
- if (mobileUserAgentPrefixes.contains(prefix)) {
- return LiteDevice.MOBILE_INSTANCE;
- }
- }
- // Accept-header based detection
- String accept = request.getHeader("Accept");
- if (accept != null && accept.contains("wap")) {
- return LiteDevice.MOBILE_INSTANCE;
- }
- // UserAgent keyword detection for Mobile and Tablet devices
- if (userAgent != null) {
- userAgent = userAgent.toLowerCase();
- // Android special case
- if (userAgent.contains("android") && !userAgent.contains("mobile")) {
- return LiteDevice.TABLET_INSTANCE;
- }
- // Kindle Fire special case
- if (userAgent.contains("silk") && !userAgent.contains("mobile")) {
- return LiteDevice.TABLET_INSTANCE;
- }
- for (String keyword : tabletUserAgentKeywords) {
- if (userAgent.contains(keyword)) {
- return LiteDevice.TABLET_INSTANCE;
- }
- }
- for (String keyword : mobileUserAgentKeywords) {
- if (userAgent.contains(keyword)) {
- return LiteDevice.MOBILE_INSTANCE;
- }
- }
- }
- // OperaMini special case
- @SuppressWarnings("rawtypes")
- Enumeration headers = request.getHeaderNames();
- while (headers.hasMoreElements()) {
- String header = (String) headers.nextElement();
- if (header.contains("OperaMini")) {
- return LiteDevice.MOBILE_INSTANCE;
- }
- }
- return resolveFallback(request);
- }
- // subclassing hooks
- /**
- * List of user agent prefixes that identify mobile devices.
- * Used primarily to match by operator or handset manufacturer.
- */
- protected List<String> getMobileUserAgentPrefixes() {
- return mobileUserAgentPrefixes;
- }
- /**
- * List of user agent keywords that identify mobile devices.
- * Used primarily to match by mobile platform or operating system.
- */
- protected List<String> getMobileUserAgentKeywords() {
- return mobileUserAgentKeywords;
- }
- /**
- * List of user agent keywords that identify tablet devices.
- * Used primarily to match by tablet platform or operating system.
- */
- protected List<String> getTabletUserAgentKeywords() {
- return tabletUserAgentKeywords;
- }
- /**
- * List of user agent keywords that identify normal devices.
- * Any items in this list take precedence over the mobile and
- * tablet user agent keywords, effectively overriding those.
- */
- protected List<String> getNormalUserAgentKeywords() {
- return normalUserAgentKeywords;
- }
- /**
- * Initialize this device resolver implementation.
- * Registers the known set of device signature strings.
- * Subclasses may override to register additional strings.
- */
- protected void init() {
- getMobileUserAgentPrefixes().addAll(Arrays.asList(KNOWN_MOBILE_USER_AGENT_PREFIXES));
- getMobileUserAgentKeywords().addAll(Arrays.asList(KNOWN_MOBILE_USER_AGENT_KEYWORDS));
- getTabletUserAgentKeywords().addAll(Arrays.asList(KNOWN_TABLET_USER_AGENT_KEYWORDS));
- }
- /**
- * Fallback called if no mobile device is matched by this resolver.
- * The default implementation of this method returns a "normal" {@link Device} that is neither mobile or a tablet.
- * Subclasses may override to try additional mobile or tablet device matching before falling back to a "normal" device.
- */
- protected Device resolveFallback(HttpServletRequest request) {
- return LiteDevice.NORMAL_INSTANCE;
- }
- // internal helpers
- private static final String[] KNOWN_MOBILE_USER_AGENT_PREFIXES = new String[] { "w3c ", "w3c-", "acs-", "alav",
- "alca", "amoi", "audi", "avan", "benq", "bird", "blac", "blaz", "brew", "cell", "cldc", "cmd-", "dang",
- "doco", "eric", "hipt", "htc_", "inno", "ipaq", "ipod", "jigs", "kddi", "keji", "leno", "lg-c", "lg-d",
- "lg-g", "lge-", "lg/u", "maui", "maxo", "midp", "mits", "mmef", "mobi", "mot-", "moto", "mwbp", "nec-",
- "newt", "noki", "palm", "pana", "pant", "phil", "play", "port", "prox", "qwap", "sage", "sams", "sany",
- "sch-", "sec-", "send", "seri", "sgh-", "shar", "sie-", "siem", "smal", "smar", "sony", "sph-", "symb",
- "t-mo", "teli", "tim-", "tosh", "tsm-", "upg1", "upsi", "vk-v", "voda", "wap-", "wapa", "wapi", "wapp",
- "wapr", "webc", "winw", "winw", "xda ", "xda-" };
- private static final String[] KNOWN_MOBILE_USER_AGENT_KEYWORDS = new String[] { "blackberry", "webos", "ipod",
- "lge vx", "midp", "maemo", "mmp", "mobile", "netfront", "hiptop", "nintendo DS", "novarra", "openweb",
- "opera mobi", "opera mini", "palm", "psp", "phone", "smartphone", "symbian", "up.browser", "up.link",
- "wap", "windows ce" };
- private static final String[] KNOWN_TABLET_USER_AGENT_KEYWORDS = new String[] { "ipad", "playbook", "hp-tablet",
- "kindle" };
- }