20230531 java.util.Objects

介绍

• java.util.Objects
• public final class Objects

API

static

• equals
• deepEquals
  • 比较数组元素
• hashCode
• hash
  • 为一系列输入值生成哈希码
• toString
  • String toString(Object o)
  • String toString(Object o, String nullDefault)
• compare
  • <T> int compare(T a, T b, Comparator<? super T> c)

null 判断，抛出 NullPointerException

• isNull
• nonNull
• requireNonNull
  • <T> T requireNonNull(T obj)
  • <T> T requireNonNull(T obj, String message)
  • <T> T requireNonNull(T obj, Supplier<String> messageSupplier)
• requireNonNullElse
  • <T> T requireNonNullElse(T obj, T defaultObj)
• requireNonNullElseGet
  • <T> T requireNonNullElseGet(T obj, Supplier<? extends T> supplier)

检查索引越界，抛出 IndexOutOfBoundsException

• checkIndex
  • int checkIndex(int index, int length)
  • long checkIndex(long index, long length)
• checkFromToIndex
  • int checkFromToIndex(int fromIndex, int toIndex, int length)
  • long checkFromToIndex(long fromIndex, long toIndex, long length)
• checkFromIndexSize
  • int checkFromIndexSize(int fromIndex, int size, int length)
  • long checkFromIndexSize(long fromIndex, long size, long length)