生成随即的数值

 1 Random rand = new Random();
 2 
 3 // Random integers
 4 int i = rand.nextInt();
 5 // Continually call nextInt() for more random integers ...
 6 
 7 // Random integers that range from from 0 to n
 8 int n = 10;
 9 i = rand.nextInt(n+1);
10 
11 // Random bytes
12 byte[] bytes = new byte[5];
13 rand.nextBytes(bytes);
14 
15 // Other primitive types
16 boolean b = rand.nextBoolean();
17 long l = rand.nextLong();
18 float f = rand.nextFloat();     // 0.0 <= f < 1.0
19 double d = rand.nextDouble();   // 0.0 <= d < 1.0
20 
21 
22 // Create two random number generators with the same seed
23 long seed = rand.nextLong();
24 rand = new Random(seed);
25 Random rand2 = new Random(seed);
26