本文整理了Java中java.util.Comparator类的一些代码示例，展示了Comparator类的具体用法。这些代码示例主要来源于Github/Stackoverflow/Maven等平台，是从一些精选项目中提取出来的代码，具有较强的参考意义，能在一定程度帮忙到你。Comparator类的具体详情如下：
包路径：java.util.Comparator
类名称：Comparator

Comparator介绍

[英]A Comparator is used to compare two objects to determine their ordering with respect to each other. On a given Collection, a Comparator can be used to obtain a sorted Collection which is totally ordered. For a Comparatorto be consistent with equals, its {code #compare(Object, Object)} method has to return zero for each pair of elements (a,b) where a.equals(b) holds true. It is recommended that a Comparator implements java.io.Serializable.
[中]比较器用于比较两个对象，以确定它们之间的顺序。在给定集合上，可以使用比较器获得完全有序的已排序集合。为了使comparator与equals一致，它的{code#compare（Object，Object）}方法必须为a.equals（b）为真的每对元素（a，b）返回零。建议比较器实现java。木卫一。可序列化。

代码示例

代码示例来源：origin: square/okhttp

public static int indexOf(Comparator<String> comparator, String[] array, String value) {
 for (int i = 0, size = array.length; i < size; i++) {
  if (comparator.compare(array[i], value) == 0) return i;
 }
 return -1;
}

代码示例来源：origin: hs-web/hsweb-framework

private static Map<String, ClassProperty> createProperty(Class type) {
  List<String> fieldNames = Arrays.stream(type.getDeclaredFields())
      .map(Field::getName).collect(Collectors.toList());
  return Stream.of(propertyUtils.getPropertyDescriptors(type))
      .filter(property -> !property.getName().equals("class") && property.getReadMethod() != null && property.getWriteMethod() != null)
      .map(BeanClassProperty::new)
      //让字段有序
      .sorted(Comparator.comparing(property -> fieldNames.indexOf(property.name)))
      .collect(Collectors.toMap(ClassProperty::getName, Function.identity(), (k, k2) -> k, LinkedHashMap::new));
}

代码示例来源：origin: goldmansachs/gs-collections

@Benchmark
public void serial_lazy_jdk()
{
  Map<Alphagram, List<String>> groupBy = this.jdkWords.stream().collect(Collectors.groupingBy(Alphagram::new));
  groupBy.entrySet()
      .stream()
      .map(Map.Entry::getValue)
      .filter(list -> list.size() >= SIZE_THRESHOLD)
      .sorted(Comparator.<List<String>>comparingInt(List::size).reversed())
      .map(list -> list.size() + ": " + list)
      .forEach(e -> Assert.assertFalse(e.isEmpty()));
}

代码示例来源：origin: dropwizard/dropwizard

@Override
  public int compare(EndpointLogLine endpointA, EndpointLogLine endpointB) {
    return Comparator.<EndpointLogLine, String>comparing(endpoint -> endpoint.basePath)
        .thenComparing(endpoint -> endpoint.httpMethod, Comparator.nullsLast(Comparator.naturalOrder()))
        .compare(endpointA, endpointB);
  }
}

代码示例来源：origin: apache/incubator-druid

@Override
public Comparator<String> getComparator()
{
 return Comparator.nullsFirst(Comparator.naturalOrder());
}

代码示例来源：origin: google/guava

/**
 * Returns a comparator of {@link Optional} values which treats {@link Optional#empty} as less
 * than all other values, and orders the rest using {@code valueComparator} on the contained
 * value.
 *
 * @since 22.0
 */
@Beta
public static <T> Comparator<Optional<T>> emptiesFirst(Comparator<? super T> valueComparator) {
 checkNotNull(valueComparator);
 return Comparator.comparing(o -> o.orElse(null), Comparator.nullsFirst(valueComparator));
}

代码示例来源：origin: apache/flink

default List<MessageHeaders> getSpecs() {
    Comparator<String> comparator = new RestServerEndpoint.RestHandlerUrlComparator.CaseInsensitiveOrderComparator();
    return initializeHandlers(CompletableFuture.completedFuture(null)).stream()
      .map(tuple -> tuple.f0)
      .filter(spec -> spec instanceof MessageHeaders)
      .map(spec -> (MessageHeaders) spec)
      .sorted((spec1, spec2) -> comparator.compare(spec1.getTargetRestEndpointURL(), spec2.getTargetRestEndpointURL()))
      .collect(Collectors.toList());
  }
}

代码示例来源：origin: biezhi/learn-java8

.filter(transaction -> transaction.year == 2011)
.sorted(Comparator.comparing(Transaction::getValue))
.collect(Collectors.toList());
.map(Trader::getCity)
.distinct()
.collect(Collectors.toList());
.map(Transaction::getTrader)
.filter(trader -> trader.getCity().equals("Cambridge"))
.sorted(Comparator.comparing(Trader::getName))
.collect(Collectors.toList());
.map(Transaction::getTrader)
.map(Trader::getName)
.sorted(Comparator.naturalOrder())
.collect(Collectors.toList());
.mapToInt(Transaction::getValue)
.max();

代码示例来源：origin: SonarSource/sonarqube

private void writeScannerProps(BufferedWriter fileWriter, Map<String, String> props) throws IOException {
 for (Map.Entry<String, String> prop : props.entrySet().stream().sorted(Comparator.comparing(Map.Entry::getKey)).collect(toList())) {
  if (isSystemProp(prop.getKey()) || isEnvVariable(prop.getKey()) || !isSqProp(prop.getKey())) {
   continue;
  }
  dumpPropIfNotSensitive(fileWriter, prop.getKey(), prop.getValue());
 }
}

代码示例来源：origin: Alluxio/alluxio

private List<URIStatus> sortByFieldAndOrder(
    List<URIStatus> statuses, String sortField, boolean reverse) throws IOException {
 Optional<Comparator<URIStatus>> sortToUse = Optional.ofNullable(
     SORT_FIELD_COMPARATORS.get(sortField));
 if (!sortToUse.isPresent()) {
  throw new InvalidArgumentException(ExceptionMessage.INVALID_ARGS_SORT_FIELD
    .getMessage(sortField));
 }
 Comparator<URIStatus> sortBy = sortToUse.get();
 if (reverse) {
  sortBy = sortBy.reversed();
 }
 return statuses.stream().sorted(sortBy).collect(Collectors.toList());
}

代码示例来源：origin: SonarSource/sonarqube

protected void assertResultOrder(String query, String... resultsInOrder) {
 ComponentDto project = indexProject("key-1", "Quality Product");
 List<ComponentDto> files = Arrays.stream(resultsInOrder)
  .map(r -> ComponentTesting.newFileDto(project).setName(r))
  .peek(f -> f.setUuid(f.uuid() + "_" + f.name().replaceAll("[^a-zA-Z0-9]", "")))
  .collect(Collectors.toList());
 // index them, but not in the expected order
 files.stream()
  .sorted(Comparator.comparing(ComponentDto::uuid).reversed())
  .forEach(this::index);
 assertExactResults(query, files.toArray(new ComponentDto[0]));
}

代码示例来源：origin: SonarSource/sonarqube

@Override
public Optional<ReadError> read(DbFileSources.Line.Builder lineBuilder) {
 Predicate<Map.Entry<TextBlock, Integer>> containsLine = new TextBlockContainsLine(lineBuilder.getLine());
 // list is sorted to cope with the non-guaranteed order of Map entries which would trigger false detection of changes
 // in {@link DbFileSources.Line#getDuplicationList()}
 duplicatedTextBlockIndexByTextBlock.entrySet().stream()
  .filter(containsLine)
  .map(Map.Entry::getValue)
  .sorted(Comparator.naturalOrder())
  .forEach(lineBuilder::addDuplication);
 return Optional.empty();
}

代码示例来源：origin: prestodb/presto

public Expression toPredicate(TupleDomain<Symbol> tupleDomain)
{
  if (tupleDomain.isNone()) {
    return FALSE_LITERAL;
  }
  Map<Symbol, Domain> domains = tupleDomain.getDomains().get();
  return domains.entrySet().stream()
      .sorted(comparing(entry -> entry.getKey().getName()))
      .map(entry -> toPredicate(entry.getValue(), entry.getKey().toSymbolReference()))
      .collect(collectingAndThen(toImmutableList(), ExpressionUtils::combineConjuncts));
}

代码示例来源：origin: spring-projects/spring-framework

@Test
public void testStringArrayToResourceArray() {
  conversionService.addConverter(new MyStringArrayToResourceArrayConverter());
  Resource[] converted = conversionService.convert(new String[] { "x1", "z3" }, Resource[].class);
  List<String> descriptions = Arrays.stream(converted).map(Resource::getDescription).sorted(naturalOrder()).collect(toList());
  assertEquals(Arrays.asList("1", "3"), descriptions);
}

代码示例来源：origin: zstackio/zstack

logger.debug(String.format("before PrimaryStoragePrioritySortFlow adjustCandidates: %s", candidates.stream().map(HostInventory::getName).collect(Collectors.toList())));
String psPriorityCondition = String.join(" ", priMap.stream()
    .map(it -> String.format("when '%s' then %d", it.PS, it.priority))
    .collect(Collectors.toList()));
logger.debug(String.format("ps priority condition : %s", psPriorityCondition));
    " and pr.uuid=ref.primaryStorageUuid " +
    " group by h.uuid", Tuple.class)
    .param("huuids", candidates.stream().map(HostInventory::getUuid).collect(Collectors.toList()))
    .param("defaultPriority", defaultPriroty)
    .list();
    .peek(it -> hostPriority.put(it.get(1, String.class), it.get(0, Integer.class)))
    .mapToInt(it -> it.get(0, Integer.class))
    .min().orElse(defaultPriroty);
    .sorted(Comparator.comparingInt(it -> hostPriority.get(it.getUuid())))
    .collect(Collectors.toList());
candidates.clear();

代码示例来源：origin: apache/flink

private static void printJobStatusMessages(List<JobStatusMessage> jobs) {
  SimpleDateFormat dateFormat = new SimpleDateFormat("dd.MM.yyyy HH:mm:ss");
  Comparator<JobStatusMessage> startTimeComparator = (o1, o2) -> (int) (o1.getStartTime() - o2.getStartTime());
  Comparator<Map.Entry<JobStatus, List<JobStatusMessage>>> statusComparator =
    (o1, o2) -> String.CASE_INSENSITIVE_ORDER.compare(o1.getKey().toString(), o2.getKey().toString());
  Map<JobStatus, List<JobStatusMessage>> jobsByState = jobs.stream().collect(Collectors.groupingBy(JobStatusMessage::getJobState));
  jobsByState.entrySet().stream()
    .sorted(statusComparator)
    .map(Map.Entry::getValue).flatMap(List::stream).sorted(startTimeComparator)
    .forEachOrdered(job ->
      System.out.println(dateFormat.format(new Date(job.getStartTime()))
        + " : " + job.getJobId() + " : " + job.getJobName()
        + " (" + job.getJobState() + ")"));
}

代码示例来源：origin: neo4j/neo4j

@Override
  public String toString()
  {
    return params.entrySet().stream()
        .sorted( Comparator.comparing( Map.Entry::getKey ) )
        .map( entry -> entry.getKey() + "=" + obsfucateIfSecret( entry ) )
        .collect( Collectors.joining( ", ") );
  }
}

代码示例来源：origin: RankSys/RankSys

/**
 * Constructor.
 *
 * @param data preference data
 */
public PopularityRecommender(FastPreferenceData<U, I> data) {
  super(data, data);
  popList = data.getIidxWithPreferences()
      .mapToObj(iidx -> tuple(iidx, (double) data.numUsers(iidx)))
      .sorted(comparingDouble(Tuple2id::v2).reversed())
      .collect(toList());
}

代码示例来源：origin: neo4j/neo4j

public String usage()
{
  StringBuilder sb = new StringBuilder();
  if ( !namedArgs.isEmpty() )
  {
    sb.append( namedArgs.values().stream().map( NamedArgument::usage ).collect( Collectors.joining( " " ) ) );
  }
  if ( !positionalArgs.isEmpty() )
  {
    sb.append( " " );
    positionalArgs.sort( Comparator.comparingInt( PositionalArgument::position ) );
    sb.append( positionalArgs.stream().map( PositionalArgument::usage ).collect( Collectors.joining( " " ) ) );
  }
  return sb.toString().trim();
}

代码示例来源：origin: SonarSource/sonarqube

private String printStatusesAndTypes(@Nullable Set<NodeHealth> nodeHealths) {
 if (nodeHealths == null) {
  return "<null>";
 }
 return nodeHealths.stream()
  // sort by type then status for debugging convenience
  .sorted(Comparator.<NodeHealth>comparingInt(s1 -> s1.getDetails().getType().ordinal())
   .thenComparingInt(s -> s.getStatus().ordinal()))
  .map(s -> ImmutableList.of(s.getDetails().getType().name(), s.getStatus().name()))
  .map(String::valueOf)
  .collect(Collectors.joining(","));
}