ThreadLocalRandom

java.lang.Object
- java.util.Random
- - java.util.concurrent.ThreadLocalRandom

所有已实现的接口:

Serializable
```
public class ThreadLocalRandom
extends Random
```
A random number generator isolated to the current thread. Like the global Random generator used by the Math class, a ThreadLocalRandom is initialized with an internally generated seed that may not otherwise be modified. When applicable, use of ThreadLocalRandom rather than shared Random objects in concurrent programs will typically encounter much less overhead and contention. Use of ThreadLocalRandom is particularly appropriate when multiple tasks (for example, each a ForkJoinTask) use random numbers in parallel in thread pools.
Usages of this class should typically be of the form: ThreadLocalRandom.current().nextX(...) (where X is Int, Long, etc). When all usages are of this form, it is never possible to accidently share a ThreadLocalRandom across multiple threads.
This class also provides additional commonly used bounded random generation methods.
Instances of ThreadLocalRandom are not cryptographically secure. Consider instead using SecureRandom in security-sensitive applications. Additionally, default-constructed instances do not use a cryptographically random seed unless the System#getProperty java.util.secureRandomSeed is set to true.

从以下版本开始:

1.7

另请参阅:

序列化表格

方法概要

所有方法静态方法实例方法具体方法
限定符和类型	方法	说明
`static ThreadLocalRandom`	`current()`	Returns the current thread's `ThreadLocalRandom`.
`DoubleStream`	`doubles()`	Returns an effectively unlimited stream of pseudorandom `double` values, each between zero (inclusive) and one (exclusive).
`DoubleStream`	`doubles(double randomNumberOrigin, double randomNumberBound)`	Returns an effectively unlimited stream of pseudorandom `double` values, each conforming to the given origin (inclusive) and bound (exclusive).
`DoubleStream`	`doubles(long streamSize)`	Returns a stream producing the given `streamSize` number of pseudorandom `double` values, each between zero (inclusive) and one (exclusive).
`DoubleStream`	`doubles(long streamSize, double randomNumberOrigin, double randomNumberBound)`	Returns a stream producing the given `streamSize` number of pseudorandom `double` values, each conforming to the given origin (inclusive) and bound (exclusive).
`IntStream`	`ints()`	Returns an effectively unlimited stream of pseudorandom `int` values.
`IntStream`	`ints(int randomNumberOrigin, int randomNumberBound)`	Returns an effectively unlimited stream of pseudorandom `int` values, each conforming to the given origin (inclusive) and bound (exclusive).
`IntStream`	`ints(long streamSize)`	Returns a stream producing the given `streamSize` number of pseudorandom `int` values.
`IntStream`	`ints(long streamSize, int randomNumberOrigin, int randomNumberBound)`	Returns a stream producing the given `streamSize` number of pseudorandom `int` values, each conforming to the given origin (inclusive) and bound (exclusive).
`LongStream`	`longs()`	Returns an effectively unlimited stream of pseudorandom `long` values.
`LongStream`	`longs(long streamSize)`	Returns a stream producing the given `streamSize` number of pseudorandom `long` values.
`LongStream`	`longs(long randomNumberOrigin, long randomNumberBound)`	Returns an effectively unlimited stream of pseudorandom `long` values, each conforming to the given origin (inclusive) and bound (exclusive).
`LongStream`	`longs(long streamSize, long randomNumberOrigin, long randomNumberBound)`	Returns a stream producing the given `streamSize` number of pseudorandom `long`, each conforming to the given origin (inclusive) and bound (exclusive).
`protected int`	`next(int bits)`	Generates the next pseudorandom number.
`boolean`	`nextBoolean()`	Returns a pseudorandom `boolean` value.
`double`	`nextDouble()`	Returns a pseudorandom `double` value between zero (inclusive) and one (exclusive).
`double`	`nextDouble(double bound)`	Returns a pseudorandom `double` value between 0.0 (inclusive) and the specified bound (exclusive).
`double`	`nextDouble(double origin, double bound)`	Returns a pseudorandom `double` value between the specified origin (inclusive) and bound (exclusive).
`float`	`nextFloat()`	Returns a pseudorandom `float` value between zero (inclusive) and one (exclusive).
`double`	`nextGaussian()`	Returns the next pseudorandom, Gaussian ("normally") distributed `double` value with mean `0.0` and standard deviation `1.0` from this random number generator's sequence.
`int`	`nextInt()`	Returns a pseudorandom `int` value.
`int`	`nextInt(int bound)`	Returns a pseudorandom `int` value between zero (inclusive) and the specified bound (exclusive).
`int`	`nextInt(int origin, int bound)`	Returns a pseudorandom `int` value between the specified origin (inclusive) and the specified bound (exclusive).
`long`	`nextLong()`	Returns a pseudorandom `long` value.
`long`	`nextLong(long bound)`	Returns a pseudorandom `long` value between zero (inclusive) and the specified bound (exclusive).
`long`	`nextLong(long origin, long bound)`	Returns a pseudorandom `long` value between the specified origin (inclusive) and the specified bound (exclusive).
`void`	`setSeed(long seed)`	Throws `UnsupportedOperationException`.

从类继承的方法 java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

从类继承的方法 java.util.Random
nextBytes

- 方法详细资料
  - current
```
public static ThreadLocalRandom current()
```
    Returns the current thread's ThreadLocalRandom.
    
    返回:
    
    the current thread's ThreadLocalRandom
  - setSeed
```
public void setSeed(long seed)
```
    Throws UnsupportedOperationException. Setting seeds in this generator is not supported.
    
    覆盖:
    
    setSeed 在类中 Random
    
    参数:
    
    seed - the initial seed
    
    抛出:
    
    UnsupportedOperationException - always
  - next
```
protected int next(int bits)
```
    从类复制的说明: Random
    Generates the next pseudorandom number. Subclasses should override this, as this is used by all other methods.
    The general contract of next is that it returns an int value and if the argument bits is between 1 and 32 (inclusive), then that many low-order bits of the returned value will be (approximately) independently chosen bit values, each of which is (approximately) equally likely to be 0 or 1. The method next is implemented by class Random by atomically updating the seed to
```
(seed * 0x5DEECE66DL + 0xBL) & ((1L << 48) - 1)
```
    and returning
```
(int)(seed >>> (48 - bits)).
```
    This is a linear congruential pseudorandom number generator, as defined by D. H. Lehmer and described by Donald E. Knuth in The Art of Computer Programming, Volume 3: Seminumerical Algorithms, section 3.2.1.
    覆盖:
    
    next 在类中 Random
    
    参数:
    
    bits - random bits
    
    返回:
    
    the next pseudorandom value from this random number generator's sequence
  - nextInt
```
public int nextInt()
```
    Returns a pseudorandom int value.
    
    覆盖:
    
    nextInt 在类中 Random
    
    返回:
    
    a pseudorandom int value
  - nextInt
```
public int nextInt(int bound)
```
    Returns a pseudorandom int value between zero (inclusive) and the specified bound (exclusive).
    
    覆盖:
    
    nextInt 在类中 Random
    
    参数:
    
    bound - the upper bound (exclusive). Must be positive.
    
    返回:
    
    a pseudorandom int value between zero (inclusive) and the bound (exclusive)
    
    抛出:
    
    IllegalArgumentException - if bound is not positive
  - nextInt
```
public int nextInt(int origin,
                   int bound)
```
    Returns a pseudorandom int value between the specified origin (inclusive) and the specified bound (exclusive).
    
    参数:
    
    origin - the least value returned
    
    bound - the upper bound (exclusive)
    
    返回:
    
    a pseudorandom int value between the origin (inclusive) and the bound (exclusive)
    
    抛出:
    
    IllegalArgumentException - if origin is greater than or equal to bound
  - nextLong
```
public long nextLong()
```
    Returns a pseudorandom long value.
    
    覆盖:
    
    nextLong 在类中 Random
    
    返回:
    
    a pseudorandom long value
  - nextLong
```
public long nextLong(long bound)
```
    Returns a pseudorandom long value between zero (inclusive) and the specified bound (exclusive).
    
    参数:
    
    bound - the upper bound (exclusive). Must be positive.
    
    返回:
    
    a pseudorandom long value between zero (inclusive) and the bound (exclusive)
    
    抛出:
    
    IllegalArgumentException - if bound is not positive
  - nextLong
```
public long nextLong(long origin,
                     long bound)
```
    Returns a pseudorandom long value between the specified origin (inclusive) and the specified bound (exclusive).
    
    参数:
    
    origin - the least value returned
    
    bound - the upper bound (exclusive)
    
    返回:
    
    a pseudorandom long value between the origin (inclusive) and the bound (exclusive)
    
    抛出:
    
    IllegalArgumentException - if origin is greater than or equal to bound
  - nextDouble
```
public double nextDouble()
```
    Returns a pseudorandom double value between zero (inclusive) and one (exclusive).
    
    覆盖:
    
    nextDouble 在类中 Random
    
    返回:
    
    a pseudorandom double value between zero (inclusive) and one (exclusive)
    
    另请参阅:
    
    Math.random()
  - nextDouble
```
public double nextDouble(double bound)
```
    Returns a pseudorandom double value between 0.0 (inclusive) and the specified bound (exclusive).
    
    参数:
    
    bound - the upper bound (exclusive). Must be positive.
    
    返回:
    
    a pseudorandom double value between zero (inclusive) and the bound (exclusive)
    
    抛出:
    
    IllegalArgumentException - if bound is not positive
  - nextDouble
```
public double nextDouble(double origin,
                         double bound)
```
    Returns a pseudorandom double value between the specified origin (inclusive) and bound (exclusive).
    
    参数:
    
    origin - the least value returned
    
    bound - the upper bound (exclusive)
    
    返回:
    
    a pseudorandom double value between the origin (inclusive) and the bound (exclusive)
    
    抛出:
    
    IllegalArgumentException - if origin is greater than or equal to bound
  - nextBoolean
```
public boolean nextBoolean()
```
    Returns a pseudorandom boolean value.
    
    覆盖:
    
    nextBoolean 在类中 Random
    
    返回:
    
    a pseudorandom boolean value
  - nextFloat
```
public float nextFloat()
```
    Returns a pseudorandom float value between zero (inclusive) and one (exclusive).
    
    覆盖:
    
    nextFloat 在类中 Random
    
    返回:
    
    a pseudorandom float value between zero (inclusive) and one (exclusive)
  - nextGaussian
```
public double nextGaussian()
```
    从类复制的说明: Random
    Returns the next pseudorandom, Gaussian ("normally") distributed double value with mean 0.0 and standard deviation 1.0 from this random number generator's sequence.
    The general contract of nextGaussian is that one double value, chosen from (approximately) the usual normal distribution with mean 0.0 and standard deviation 1.0, is pseudorandomly generated and returned.
    The method nextGaussian is implemented by class Random as if by a threadsafe version of the following:
```
 
 private double nextNextGaussian;
 private boolean haveNextNextGaussian = false;

 public double nextGaussian() {
   if (haveNextNextGaussian) {
     haveNextNextGaussian = false;
     return nextNextGaussian;
   } else {
     double v1, v2, s;
     do {
       v1 = 2 * nextDouble() - 1;   // between -1.0 and 1.0
       v2 = 2 * nextDouble() - 1;   // between -1.0 and 1.0
       s = v1 * v1 + v2 * v2;
     } while (s >= 1 || s == 0);
     double multiplier = StrictMath.sqrt(-2 * StrictMath.log(s)/s);
     nextNextGaussian = v2 * multiplier;
     haveNextNextGaussian = true;
     return v1 * multiplier;
   }
 }
```
    This uses the polar method of G. E. P. Box, M. E. Muller, and G. Marsaglia, as described by Donald E. Knuth in The Art of Computer Programming, Volume 3: Seminumerical Algorithms, section 3.4.1, subsection C, algorithm P. Note that it generates two independent values at the cost of only one call to StrictMath.log and one call to StrictMath.sqrt.
    覆盖:
    
    nextGaussian 在类中 Random
    
    返回:
    
    the next pseudorandom, Gaussian ("normally") distributed double value with mean 0.0 and standard deviation 1.0 from this random number generator's sequence
  - ints
```
public IntStream ints(long streamSize)
```
    Returns a stream producing the given streamSize number of pseudorandom int values.
    
    覆盖:
    
    ints 在类中 Random
    
    参数:
    
    streamSize - the number of values to generate
    
    返回:
    
    a stream of pseudorandom int values
    
    抛出:
    
    IllegalArgumentException - if streamSize is less than zero
    
    从以下版本开始:
    
    1.8
  - ints
```
public IntStream ints()
```
    Returns an effectively unlimited stream of pseudorandom int values.
    
    覆盖:
    
    ints 在类中 Random
    
    返回:
    
    a stream of pseudorandom int values
    
    从以下版本开始:
    
    1.8
  - ints
```
public IntStream ints(long streamSize,
                      int randomNumberOrigin,
                      int randomNumberBound)
```
    Returns a stream producing the given streamSize number of pseudorandom int values, each conforming to the given origin (inclusive) and bound (exclusive).
    
    覆盖:
    
    ints 在类中 Random
    
    参数:
    
    streamSize - the number of values to generate
    
    randomNumberOrigin - the origin (inclusive) of each random value
    
    randomNumberBound - the bound (exclusive) of each random value
    
    返回:
    
    a stream of pseudorandom int values, each with the given origin (inclusive) and bound (exclusive)
    
    抛出:
    
    IllegalArgumentException - if streamSize is less than zero, or randomNumberOrigin is greater than or equal to randomNumberBound
    
    从以下版本开始:
    
    1.8
  - ints
```
public IntStream ints(int randomNumberOrigin,
                      int randomNumberBound)
```
    Returns an effectively unlimited stream of pseudorandom int values, each conforming to the given origin (inclusive) and bound (exclusive).
    
    覆盖:
    
    ints 在类中 Random
    
    参数:
    
    randomNumberOrigin - the origin (inclusive) of each random value
    
    randomNumberBound - the bound (exclusive) of each random value
    
    返回:
    
    a stream of pseudorandom int values, each with the given origin (inclusive) and bound (exclusive)
    
    抛出:
    
    IllegalArgumentException - if randomNumberOrigin is greater than or equal to randomNumberBound
    
    从以下版本开始:
    
    1.8
  - longs
```
public LongStream longs(long streamSize)
```
    Returns a stream producing the given streamSize number of pseudorandom long values.
    
    覆盖:
    
    longs 在类中 Random
    
    参数:
    
    streamSize - the number of values to generate
    
    返回:
    
    a stream of pseudorandom long values
    
    抛出:
    
    IllegalArgumentException - if streamSize is less than zero
    
    从以下版本开始:
    
    1.8
  - longs
```
public LongStream longs()
```
    Returns an effectively unlimited stream of pseudorandom long values.
    
    覆盖:
    
    longs 在类中 Random
    
    返回:
    
    a stream of pseudorandom long values
    
    从以下版本开始:
    
    1.8
  - longs
```
public LongStream longs(long streamSize,
                        long randomNumberOrigin,
                        long randomNumberBound)
```
    Returns a stream producing the given streamSize number of pseudorandom long, each conforming to the given origin (inclusive) and bound (exclusive).
    
    覆盖:
    
    longs 在类中 Random
    
    参数:
    
    streamSize - the number of values to generate
    
    randomNumberOrigin - the origin (inclusive) of each random value
    
    randomNumberBound - the bound (exclusive) of each random value
    
    返回:
    
    a stream of pseudorandom long values, each with the given origin (inclusive) and bound (exclusive)
    
    抛出:
    
    IllegalArgumentException - if streamSize is less than zero, or randomNumberOrigin is greater than or equal to randomNumberBound
    
    从以下版本开始:
    
    1.8
  - longs
```
public LongStream longs(long randomNumberOrigin,
                        long randomNumberBound)
```
    Returns an effectively unlimited stream of pseudorandom long values, each conforming to the given origin (inclusive) and bound (exclusive).
    
    覆盖:
    
    longs 在类中 Random
    
    参数:
    
    randomNumberOrigin - the origin (inclusive) of each random value
    
    randomNumberBound - the bound (exclusive) of each random value
    
    返回:
    
    a stream of pseudorandom long values, each with the given origin (inclusive) and bound (exclusive)
    
    抛出:
    
    IllegalArgumentException - if randomNumberOrigin is greater than or equal to randomNumberBound
    
    从以下版本开始:
    
    1.8
  - doubles
```
public DoubleStream doubles(long streamSize)
```
    Returns a stream producing the given streamSize number of pseudorandom double values, each between zero (inclusive) and one (exclusive).
    
    覆盖:
    
    doubles 在类中 Random
    
    参数:
    
    streamSize - the number of values to generate
    
    返回:
    
    a stream of double values
    
    抛出:
    
    IllegalArgumentException - if streamSize is less than zero
    
    从以下版本开始:
    
    1.8
  - doubles
```
public DoubleStream doubles()
```
    Returns an effectively unlimited stream of pseudorandom double values, each between zero (inclusive) and one (exclusive).
    
    覆盖:
    
    doubles 在类中 Random
    
    返回:
    
    a stream of pseudorandom double values
    
    从以下版本开始:
    
    1.8
  - doubles
```
public DoubleStream doubles(long streamSize,
                            double randomNumberOrigin,
                            double randomNumberBound)
```
    Returns a stream producing the given streamSize number of pseudorandom double values, each conforming to the given origin (inclusive) and bound (exclusive).
    
    覆盖:
    
    doubles 在类中 Random
    
    参数:
    
    streamSize - the number of values to generate
    
    randomNumberOrigin - the origin (inclusive) of each random value
    
    randomNumberBound - the bound (exclusive) of each random value
    
    返回:
    
    a stream of pseudorandom double values, each with the given origin (inclusive) and bound (exclusive)
    
    抛出:
    
    IllegalArgumentException - if streamSize is less than zero
    
    IllegalArgumentException - if randomNumberOrigin is greater than or equal to randomNumberBound
    
    从以下版本开始:
    
    1.8
  - doubles
```
public DoubleStream doubles(double randomNumberOrigin,
                            double randomNumberBound)
```
    Returns an effectively unlimited stream of pseudorandom double values, each conforming to the given origin (inclusive) and bound (exclusive).
    
    覆盖:
    
    doubles 在类中 Random
    
    参数:
    
    randomNumberOrigin - the origin (inclusive) of each random value
    
    randomNumberBound - the bound (exclusive) of each random value
    
    返回:
    
    a stream of pseudorandom double values, each with the given origin (inclusive) and bound (exclusive)
    
    抛出:
    
    IllegalArgumentException - if randomNumberOrigin is greater than or equal to randomNumberBound
    
    从以下版本开始:
    
    1.8

类 ThreadLocalRandom

方法概要

从类继承的方法 java.lang.Object

从类继承的方法 java.util.Random

方法详细资料

current

setSeed

next

nextInt

nextInt

nextInt

nextLong

nextLong

nextLong

nextDouble

nextDouble

nextDouble

nextBoolean

nextFloat

nextGaussian

ints

ints

ints

ints

longs

longs

longs

longs

doubles

doubles

doubles

doubles