Java编程思想学习笔记（—）

Java编程思想学习笔记（—）

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（美） Bruce Eckel 著 《Java编程思想》部分学习日记（随手记录的笔记）

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???????? 代码：

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public class JavaTest {      /**       * @param args       */      public static void main(String[] args) {            // TODO Auto-generated method stub            Dog spot = new Dog();            spot.name = "zengxiao";            spot.say = "汪汪";            Dog spot1 =new Dog();            spot1.name ="zengxiao";            spot1.say="汪汪";            Integer intNum =new Integer(47);            Integer intNum1 =new Integer(47);            System.out.println(intNum==intNum1);            System.out.println(intNum.equals(intNum1));            System.out.println(spot==spot1);            System.out.println(spot.equals(spot1));      }}class Dog {      String name;      String say;}

?输出的结果就是：
? false
? true
? false
? false

??????? 代码：

public class JavaTest {      /**       * @param args       */      public static void main(String[] args) {            // TODO Auto-generated method stub        int i1= 0x2f;        System.out.println(Integer.toBinaryString(i1));        long l1 =02567;        System.out.println(Long.toBinaryString(l1));      }}

? ?把十六进制和八进制转化成二进制的数时用，toBinaryString

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生成一个随机小写字母的方法：

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Random rnd = new Random();char c =(char)(rnd.nextInt(26)+'a');

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??? 生成随机数的方法：

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            Random rnd = new Random();            ArrayList<Integer> listInt = new ArrayList();            int i = 0;            while (i < 25) {                  int j =rnd.nextInt(500);                  if (!listInt.contains(j)) {                        listInt.add(j);                        i++;                  }            }            for (Integer integer : listInt) {                  System.out.println(integer);            }

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??? Arrays.toString()将产生一维数组的可打印版本

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public class JavaTest {      /**       * @param args       */      public static void main(String[] args) {            // TODO Auto-generated method stub     Random rndRandom =new Random();     int[] intNum =new int[rndRandom.nextInt(20)];     System.out.println(intNum.length);     for (int i = 0; i < intNum.length; i++) {            intNum[i]=rndRandom.nextInt(200);      }            System.out.println(Arrays.toString(intNum));      }}

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??代码：

public class JavaTest {      /**       * @param args       */      public static void main(String[] args) {            // TODO Auto-generated method stub        for (Spiciness s : Spiciness.values()) {                  System.out.println(s+",ordinal"+s.ordinal());            }      }      public enum Spiciness {            Not,mild,zengxiao,zeng,xiao      }}

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