java Random.nextInt()方法

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public int nextInt(int n)

該方法的作用是產生一個隨機的int值，該值介於[0,n)的區間，也就是0到n之間的隨機int值，包含0而不包含n。

 

直接上代碼：

package org.xiaowu.random.demo;import java.util.Random;import org.junit.Test;public class RandomDemo {        @Test    public void Demo(){        Random rnd = new Random();        int code = rnd.nextInt(8999) + 1000;        System.out.println("code:"+code);    }        @Test    public void Demo1(){        Random r = new Random();        int nextInt = r.nextInt();        Random r1 = new Random(10);        int nextInt2 = r1.nextInt();        System.out.println("nextInt:"+nextInt);        System.out.println("nextInt2:"+nextInt2);    }        /**     * 產生[0,1.0)區間的小數     *      */    @Test    public void Demo2(){        Random r = new Random();        double d1 = r.nextDouble();        System.out.println("d1:"+d1);    }        /**     * 產生[0,5.0)區間的小數     *      */    @Test    public void Demo3(){        Random r = new Random();        double d2 = r.nextDouble()* 5;        System.out.println("d1:"+d2);    }        /**     * 產生[1,2.5)區間的小數     *      */    @Test    public void Demo4(){        Random r = new Random();        double d3 = r.nextDouble() * 1.5 + 1;        System.out.println("d1:"+d3);    }        /**     * 產生任意整數     *      */    @Test    public void Demo5(){        Random r = new Random();        int n1 = r.nextInt();        System.out.println("d1:"+n1);    }            /**     * 產生[0,10)區間的整數     *      */    @Test    public void Demo6(){        Random r = new Random();        int n2 = r.nextInt(10);        int n3 = Math.abs(r.nextInt() % 10);        System.out.println("n2:"+n2);        System.out.println("n3:"+n3);    }            /**     * 產生[0,10]區間的整數     *      */    @Test    public void Demo7(){        Random r = new Random();        int n3 = r.nextInt(11);        int n4 = Math.abs(r.nextInt() % 11);        System.out.println("n3:"+n3);        System.out.println("n4:"+n4);    }        /**     * 產生[-3,15)區間的整數     *      */    @Test    public void Demo8(){        Random r = new Random();        int n4 = r.nextInt(18) - 3;        int n5 = Math.abs(r.nextInt() % 18) - 3;        System.out.println("n4:"+n4);        System.out.println("n5:"+n5);    }    }

 

java Random.nextInt()方法