public class CollectorKit extends Object
| 限定符和类型 | 字段 | 说明 |
|---|---|---|
static Collector.Characteristics[] |
CH_ALL |
|
static Collector.Characteristics[] |
CH_CONCURRENT |
|
static Collector.Characteristics[] |
CH_CONCURRENT_ID |
|
static Collector.Characteristics[] |
CH_CONCURRENT_UNORDERED |
|
static Collector.Characteristics[] |
CH_EMPTY |
|
static Collector.Characteristics[] |
CH_ID |
|
static Collector.Characteristics[] |
CH_UNORDERED |
|
static Collector.Characteristics[] |
CH_UNORDERED_ID |
| 限定符 | 构造器 | 说明 |
|---|---|---|
private |
CollectorKit() |
| 限定符和类型 | 方法 | 说明 |
|---|---|---|
static <T,K> Collector<T,?,Map<K,List<T>>> |
groupingByAllowNullKey(Function<? super T,? extends K> classifier) |
创建一个Map分组收集器,允许key为null
|
private static void |
throwDuplicateKeyException(Object key) |
|
static <T,K,U,M extends Map<K,U>> |
toConcurrentMap(Function<? super T,? extends K> keyMapper,
Function<? super T,? extends U> valueMapper) |
|
static <T,K,U,M extends Map<K,U>> |
toConcurrentMap(Function<? super T,? extends K> keyMapper,
Function<? super T,? extends U> valueMapper,
boolean isAllowDuplicateKeys) |
|
static <T,K,U,M extends Map<K,U>> |
toLinkedMap(Function<? super T,? extends K> keyMapper,
Function<? super T,? extends U> valueMapper) |
|
static <T,K,U,M extends Map<K,U>> |
toLinkedMap(Function<? super T,? extends K> keyMapper,
Function<? super T,? extends U> valueMapper,
boolean isAllowDuplicateKeys) |
|
static <T,K,U,M extends Map<K,U>> |
toMap(Function<? super T,? extends K> keyMapper,
Function<? super T,? extends U> valueMapper) |
|
static <T,K,U,M extends Map<K,U>> |
toMap(Function<? super T,? extends K> keyMapper,
Function<? super T,? extends U> valueMapper,
boolean isAllowDuplicateKeys) |
|
static <T,K,U,M extends Map<K,U>> |
toMap(Supplier<M> mapSupplier,
Function<? super T,? extends K> keyMapper,
Function<? super T,? extends U> valueMapper,
boolean isAllowDuplicateKeys) |
创建一个Map收集器
|
public static final Collector.Characteristics[] CH_ALL
public static final Collector.Characteristics[] CH_CONCURRENT_UNORDERED
public static final Collector.Characteristics[] CH_CONCURRENT_ID
public static final Collector.Characteristics[] CH_UNORDERED_ID
public static final Collector.Characteristics[] CH_CONCURRENT
public static final Collector.Characteristics[] CH_UNORDERED
public static final Collector.Characteristics[] CH_ID
public static final Collector.Characteristics[] CH_EMPTY
public static <T,K> Collector<T,?,Map<K,List<T>>> groupingByAllowNullKey(Function<? super T,? extends K> classifier)
T - Stream流中的元素类型K - Map的Key的类型classifier - 分类器public static <T,K,U,M extends Map<K,U>> Collector<T,?,M> toMap(Supplier<M> mapSupplier, Function<? super T,? extends K> keyMapper, Function<? super T,? extends U> valueMapper, boolean isAllowDuplicateKeys)
T - Stream流中的元素类型K - Map的Key的类型U - Map的Value的类型M - MapmapSupplier - map对象提供keyMapper - map key的映射器valueMapper - map value的映射器isAllowDuplicateKeys - 是否允许相同的 key,如果 false,遇到相同的 key,抛出异常;如果 true,遇到相同的 key,则会覆盖IllegalStateException - 如果参数isAllowDuplicateKeys为 true 且转换过程存在相同的key,则抛出此异常public static <T,K,U,M extends Map<K,U>> Collector<T,?,M> toMap(Function<? super T,? extends K> keyMapper, Function<? super T,? extends U> valueMapper)
public static <T,K,U,M extends Map<K,U>> Collector<T,?,M> toMap(Function<? super T,? extends K> keyMapper, Function<? super T,? extends U> valueMapper, boolean isAllowDuplicateKeys)
public static <T,K,U,M extends Map<K,U>> Collector<T,?,M> toLinkedMap(Function<? super T,? extends K> keyMapper, Function<? super T,? extends U> valueMapper)
public static <T,K,U,M extends Map<K,U>> Collector<T,?,M> toLinkedMap(Function<? super T,? extends K> keyMapper, Function<? super T,? extends U> valueMapper, boolean isAllowDuplicateKeys)
public static <T,K,U,M extends Map<K,U>> Collector<T,?,M> toConcurrentMap(Function<? super T,? extends K> keyMapper, Function<? super T,? extends U> valueMapper)
public static <T,K,U,M extends Map<K,U>> Collector<T,?,M> toConcurrentMap(Function<? super T,? extends K> keyMapper, Function<? super T,? extends U> valueMapper, boolean isAllowDuplicateKeys)
private static void throwDuplicateKeyException(Object key)
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