java获取ip地址慢，webSocket获取ip

java 中 InetSocketAddress

 remoteAddress.getHostName() //获取hostName时耗时长，改方法要慎用；（先从本地取，如果本地没取到从远程dns中取）

remoteAddress.getAddress().getHostAddress() ； //改用这种方式获取ip

public class WebsocketUtil {

public static InetSocketAddress getRemoteAddress(Session session) {
if (session == null) {
return null;
}
Async async = session.getAsyncRemote();

//在Tomcat 8.0.x版本有效
// InetSocketAddress addr = (InetSocketAddress) getFieldInstance(async,"base#sos#socketWrapper#socket#sc#remoteAddress");
//在Tomcat 8.5以上版本有效
InetSocketAddress addr = (InetSocketAddress) getFieldInstance(async,"base#socketWrapper#socket#sc#remoteAddress");
return addr;
}

private static Object getFieldInstance(Object obj, String fieldPath) {
String fields[] = fieldPath.split("#");
for (String field : fields) {
obj = getField(obj, obj.getClass(), field);
if (obj == null) {
return null;
}
}

return obj;
}

private static Object getField(Object obj, Class<?> clazz, String fieldName) {
for (; clazz != Object.class; clazz = clazz.getSuperclass()) {
try {
Field field;
field = clazz.getDeclaredField(fieldName);
field.setAccessible(true);
return field.get(obj);
} catch (Exception e) {
}
}

return null;
}

}