java-8

问题 Is there anyway to find the standard time that comes under time zone regions, for example America/New_York and America/NewJersey -> EST I am developing a REST service where the request will have region-based timezone(America/NewJersey) as a parameter and I need to find the standard time it comes under and pass it to legacy API, which only accepts 3 digit timezone(EST/MST/CST/AET). I am using Java 8 and I checked Time API, but it doesn't have any such feature/functionality. As a workaround I

问题 I have this code, it's a simple string that I want to parse it to a LocalDateTime import java.time.LocalDateTime; import java.time.format.DateTimeFormatter; import java.time.format.DateTimeFormatterBuilder; public class DateClass { /** * @param args the command line arguments */ public static void main(String[] args) { String dateRaw = "2019-05-03 7:05:03"; DateTimeFormatter dtf = new DateTimeFormatterBuilder().appendPattern("uuuu-mm-dd HH:mm:ss").toFormatter(); LocalDateTime date=

问题 I have this code, it's a simple string that I want to parse it to a LocalDateTime import java.time.LocalDateTime; import java.time.format.DateTimeFormatter; import java.time.format.DateTimeFormatterBuilder; public class DateClass { /** * @param args the command line arguments */ public static void main(String[] args) { String dateRaw = "2019-05-03 7:05:03"; DateTimeFormatter dtf = new DateTimeFormatterBuilder().appendPattern("uuuu-mm-dd HH:mm:ss").toFormatter(); LocalDateTime date=

问题 I am trying to send a JMS message to remote ActiveMQ Artemis queue that is embedded in JBoss EAP 7.2. I have defined the following in standalone-full.xml : Remote Connector Pooled Connection Factory Remote binding <subsystem xmlns="urn:jboss:domain:messaging-activemq:4.0"> <server name="default"> <journal pool-files="10"/> <security-setting name="#"> <role name="guest" send="true" consume="true" create-non-durable-queue="true" delete-non-durable-queue="true"/> </security-setting> <address

问题 I am using Jackson 2.8.5 with ParameterNamesModule for Java 8 (https://github.com/FasterXML/jackson-modules-java8). My problem is very specific for one use case, when I want to de-serialize a class with a single constructor using a single argument. Here is a test to reproduces the behavior: public class JacksonTest { @Test public void TestReadValue() throws IOException { ObjectMapper objectMapper = new ObjectMapper() .setVisibility(PropertyAccessor.FIELD, JsonAutoDetect.Visibility.ANY)

问题 What I have: A text-file which is read line by line. Each String contains a line. What I want: Group ALL words by first character using Java Streams. What I have so far: public static Map<Character, List<String>> groupByFirstChar(String fileName) throws IOException { return Files.lines(Paths.get(PATH)). flatMap(s -> Stream.of(s.split("[^a-zA-Z]"))). map(s -> s.toLowerCase()). sorted((s1, s2) -> s1.compareTo(s2)). collect(Collectors.groupingBy(s -> s.charAt(0))); } Problem: I get an Exception

问题 Scenario : there are two stages 2nd stage is to be executed only after the 1st one is completed 2nd stage is not interested in the 1st stage result but merely in the fact that the first stage is completed Consider the existing method: public <U> CompletionStage<U> thenApply(Function<? super T,? extends U> fn); It doesn't quite satisfy my needs cause the function is aware of the 1st stage result value ? super T What I would rather like to have is something like: public <U> CompletionStage<U>

问题 I want to convert int array to Map<Integer,Integer> using Java 8 stream api int[] nums={2, 7, 11, 15, 2, 11, 2}; Map<Integer,Integer> map=Arrays .stream(nums) .collect(Collectors.toMap(e->e,1)); I want to get a map like below, key will be integer value, value will be total count of each key map={2->3, 7->1, 11->2, 15->1} compiler complains " no instance(s) of type variable(s) T, U exist so that Integer confirms to Function " appreciate any pointers to resolve this 回答1: You need to box the

问题 I want to print hi GrandFather But it seems to print hi father. And I am not understand how to diff the use between findSpecial and findVirtual I want someone can help me. Thank you class GrandFather{ void thinking(){ System.out.println("hi GrandFather"); } } class Father extends GrandFather{ void thinking(){ System.out.println("hi Father"); } } class Son extends Father{ void thinking(){ MethodType mt=MethodType.methodType(void.class); //MethodHandle mh=MethodHandles.lookup().findVirtual

问题 I need to translate between IANA timezone & windows timezone & vice-versa. There is another question reported: How to translate between Windows and IANA time zones? It specifies that Noda time library can be used in .Net Do we have any library to be used in Java? Or any other utility to be used in java? 回答1: This may be what you need, but I don't know if it will work for all your use cases: for (String tzId : TimeZone.getAvailableIDs()) { TimeZone tz = TimeZone.getTimeZone(tzId); if (tz