本文整理了Java中java.util.stream.Stream.mapToInt()方法的一些代码示例，展示了Stream.mapToInt()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。Stream.mapToInt()方法的具体详情如下：
包路径：java.util.stream.Stream
类名称：Stream
方法名：mapToInt

Stream.mapToInt介绍

[英]Returns an IntStream consisting of the results of applying the given function to the elements of this stream.

This is an intermediate operation.
[中]返回一个IntStream，该IntStream包含将给定函数应用于该流元素的结果。
这是一个intermediate operation。

代码示例

代码示例来源：origin: prestodb/presto

public InputChannels(List<Integer> inputChannels)
{
  this.inputChannels = inputChannels.stream().mapToInt(Integer::intValue).toArray();
}

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

@Override
public DefaultDataBuffer write(ByteBuffer... buffers) {
  if (!ObjectUtils.isEmpty(buffers)) {
    int capacity = Arrays.stream(buffers).mapToInt(ByteBuffer::remaining).sum();
    ensureCapacity(capacity);
    Arrays.stream(buffers).forEach(this::write);
  }
  return this;
}

代码示例来源：origin: neo4j/neo4j

private int[] getOrCreatePropertyKeyIds( String[] properties )
{
  return Arrays.stream( properties )
      .mapToInt( BatchInserterImpl.this::getOrCreatePropertyKeyId )
      .toArray();
}

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

/**
 * {@inheritDoc}
 * <p>This implementation creates a single {@link DefaultDataBuffer}
 * to contain the data in {@code dataBuffers}.
 */
@Override
public DefaultDataBuffer join(List<? extends DataBuffer> dataBuffers) {
  Assert.notEmpty(dataBuffers, "DataBuffer List must not be empty");
  int capacity = dataBuffers.stream().mapToInt(DataBuffer::readableByteCount).sum();
  DefaultDataBuffer result = allocateBuffer(capacity);
  dataBuffers.forEach(result::write);
  dataBuffers.forEach(DataBufferUtils::release);
  return result;
}

代码示例来源：origin: apache/flink

private int computeTotalMainWidth() {
  final List<AttributedString> mainLines = getMainLines();
  final List<AttributedString> mainHeaderLines = getMainHeaderLines();
  final int max1 = mainLines.stream().mapToInt(AttributedString::length).max().orElse(0);
  final int max2 = mainHeaderLines.stream().mapToInt(AttributedString::length).max().orElse(0);
  return Math.max(max1, max2);
}

代码示例来源：origin: apache/incubator-druid

public Collection<ServerHolder> getAllServers()
{
 final int historicalSize = historicals.values().stream().mapToInt(Collection::size).sum();
 final int realtimeSize = realtimes.size();
 final List<ServerHolder> allServers = new ArrayList<>(historicalSize + realtimeSize);
 historicals.values().forEach(allServers::addAll);
 allServers.addAll(realtimes);
 return allServers;
}

代码示例来源：origin: Vedenin/useful-java-links

private static void testFlatMapToInt() {
  System.out.println();
  System.out.println("Test flat map start");
  Collection<String> collection = Arrays.asList("1,2,0", "4,5");
  // Get sum all digit from strings
  int sum = collection.stream().flatMapToInt((p) -> Arrays.asList(p.split(",")).stream().mapToInt(Integer::parseInt)).sum();
  System.out.println("sum = " + sum); // print  sum = 12
}

代码示例来源：origin: stackoverflow.com

List<Integer> list = Arrays.asList(1, 2, 3, 4);
int[] arr = list.stream().mapToInt(i -> i).toArray(); //[1, 2, 3, 4]

list.set(1, null); //[1, null, 3, 4]
arr = list.stream().filter(i -> i != null).mapToInt(i -> i).toArray(); //[1, 3, 4]

代码示例来源：origin: Vedenin/useful-java-links

private static void testMapToInt() {
  System.out.println();
  System.out.println("Test mapToInt start");
  Collection<String> collection = Arrays.asList("a1", "a2", "a3", "a1");
  // Delete first char of element and returns number
  int[] number = collection.stream().mapToInt((s) -> Integer.parseInt(s.substring(1))).toArray();
  System.out.println("number = " + Arrays.toString(number)); // print  number = [1, 2, 3, 1]
}

代码示例来源：origin: shekhargulati/99-problems

public static <T> long lengthStream1(List<T> list) {
  return list.stream().mapToInt(x -> 1).sum();
}

代码示例来源：origin: prestodb/presto

public InterpretedHashGenerator(List<Type> hashChannelTypes, List<Integer> hashChannels)
{
  this(hashChannelTypes, requireNonNull(hashChannels).stream().mapToInt(i -> i).toArray());
}

代码示例来源：origin: ben-manes/caffeine

public IntStream getTopK(int k) {
 return stream.topK(k).stream().mapToInt(counter -> (int) counter.getCount());
}

代码示例来源：origin: apache/pulsar

@Override
public int getAvailablePermits() {
  return consumers.values().stream().mapToInt(ConsumerImpl::getAvailablePermits).sum();
}

代码示例来源：origin: stackoverflow.com

List<Integer> primes = Arrays.asList(2, 3, 5, 7, 11, 13, 17, 19, 23, 29);
IntSummaryStatistics stats = primes.stream()
                  .mapToInt((x) -> x)
                  .summaryStatistics();
System.out.println(stats);

代码示例来源：origin: EngineHub/WorldEdit

@Nullable
public int[] getLegacyFromItem(ItemType itemType) {
  if (!itemToStringMap.containsKey(itemType)) {
    return null;
  } else {
    String value = itemToStringMap.get(itemType).stream().findFirst().get();
    return Arrays.stream(value.split(":")).mapToInt(Integer::parseInt).toArray();
  }
}

代码示例来源：origin: apache/incubator-druid

static long requiredBufferCapacity(
  int cardinality,
  AggregatorFactory[] aggregatorFactories
)
{
 final int cardinalityWithMissingValue = cardinality + 1;
 final int recordSize = Arrays.stream(aggregatorFactories)
                .mapToInt(AggregatorFactory::getMaxIntermediateSizeWithNulls)
                .sum();
 return getUsedFlagBufferCapacity(cardinalityWithMissingValue) +  // total used flags size
   (long) cardinalityWithMissingValue * recordSize;                 // total values size
}

代码示例来源：origin: biezhi/30-seconds-of-java8

/**
 * Input a line of numbers separated by space as integers
 * and return ArrayList of Integers.
 * eg. the String "1 2 3 4 5 6 7 8 9" is returned as an ArrayList of Integers.
 *
 * @param numbers range of numbers separated by space as a string
 * @return ArrayList of Integers
 */
public static int[] stringToIntegers(String numbers) {
  return Arrays.stream(numbers.split(" ")).mapToInt(Integer::parseInt).toArray();
}

代码示例来源：origin: apache/incubator-druid

@Override
public int getQueryCount()
{
 return rels.stream().mapToInt(rel -> ((DruidRel) rel).getQueryCount()).sum();
}

代码示例来源：origin: prestodb/presto

private static Function<Page, Page> enforceLayoutProcessor(List<Symbol> expectedLayout, Map<Symbol, Integer> inputLayout)
{
  int[] channels = expectedLayout.stream()
      .peek(symbol -> checkArgument(inputLayout.containsKey(symbol), "channel not found for symbol: %s", symbol))
      .mapToInt(inputLayout::get)
      .toArray();
  if (Arrays.equals(channels, range(0, inputLayout.size()).toArray())) {
    // this is an identity mapping
    return Function.identity();
  }
  return new PageChannelSelector(channels);
}

代码示例来源：origin: prestodb/presto

private static VarcharType varcharType(List<String> values)
{
  if (values.stream().anyMatch(Objects::isNull)) {
    return VARCHAR;
  }
  return createVarcharType(values.stream().mapToInt(String::length).max().getAsInt());
}