(1)枚举类型enum
1 package JavaEE.JavaBaseExampleTest.Functions; 2 3 /** 4 * Java 创建枚举类型要使用 enum 关键字,隐含了所创建的类型都是 java.lang.Enum 类的子类 5 */ 6 7 enum Car { 8 lamborghini, fiveLight, audi, fiat, honda 9 } 10 public class EnumAndSwitch { 11 public static void main(String[] args){ 12 Car c; 13 c = Car.fiveLight; 14 switch (c){ 15 case lamborghini: 16 System.out.println("你选择了 lamborghini"); 17 break; 18 case fiveLight: 19 System.out.println("你选择了 fiveLight"); 20 break; 21 case audi: 22 System.out.println("你选择了 audi"); 23 break; 24 case fiat: 25 System.out.println("你选择了 fiat"); 26 break; 27 case honda: 28 System.out.println("你选择了 honda"); 29 break; 30 default: 31 System.out.println("我不知道你的车型..."); 32 break; 33 } 34 } 35 }
(2)枚举类型构造函数的使用
1 package JavaEE.JavaBaseExampleTest.Functions; 2 3 /** 4 * Enum(枚举)构造函数及方法的使用 5 */ 6 7 enum NewCar{ 8 lamborghini(900), tata(2), audi(50), fiat(15), honda(12); 9 private int price; 10 NewCar(int p){ 11 price = p; 12 } 13 int getPrice(){return price;} 14 } 15 public class EnumFunction { 16 public static void main(String[] args){ 17 System.out.println("所有汽车价格:"); 18 for (NewCar c:NewCar.values()) 19 System.out.println(c + "需要" + c.getPrice() + "千美元"); 20 } 21 }
(3)阶乘计算
1 package JavaEE.JavaBaseExampleTest.Functions; 2 3 /** 4 * 阶乘 5 */ 6 public class Factorial { 7 public static void main(String[] args){ 8 for (int counter = 0; counter <= 10; counter++){ 9 System.out.printf("%d! = %d\n", counter, factorial(counter)); 10 } 11 } 12 public static long factorial(long number){ 13 if (number <= 1) return 1; 14 else return number * factorial(number - 1); 15 } 16 }
(4)斐波那契数列
1 package JavaEE.JavaBaseExampleTest.Functions; 2 3 /** 4 * 斐波那契数列: 5 * 第0项是0,第1项是第一个1 6 * 这个数列从第三项开始,每一项都等于前两项之和 7 */ 8 public class Fibonacci { 9 public static void main(String[] args){ 10 for (int counter = 0; counter <= 10; counter++){ 11 System.out.printf("Fibonacci of %d is : %d\n", counter, fibonacci(counter)); 12 } 13 } 14 15 public static long fibonacci(long number) { 16 if ((number == 0 ) || (number == 1)){ 17 return number; 18 }else { 19 return fibonacci(number - 1) + fibonacci(number - 2); 20 } 21 } 22 }
(5)foreach循环遍历
1 package JavaEE.JavaBaseExampleTest.Functions; 2 3 /** 4 * foreach语句是java5的新特征之一,在遍历数组、集合方面,foreach为开发人员提供了极大的方便 5 */ 6 public class ForAndForeach { 7 public static void main(String[] args){ 8 int[] intary = {1, 2, 3, 4}; 9 forDisplay(intary); 10 foreachDisplay(intary); 11 } 12 public static void forDisplay(int[] a){ 13 System.out.println("使用 for 循环数组: "); 14 for (int i = 0; i < a.length; i++){ 15 System.out.print(a[i] + " "); 16 } 17 System.out.println(); 18 } 19 public static void foreachDisplay(int[] data){ 20 System.out.println("使用 foreach 循环数组: "); 21 for (int a:data) 22 System.out.print(a + " "); 23 } 24 }
(6)方法覆盖
1 package JavaEE.JavaBaseExampleTest.Functions; 2 3 /** 4 * 方法重载与方法覆盖区别如下: 5 * 方法重载(Overloading): 6 * 如果有两个方法的方法名相同,但参数不一致,哪么可以说一个方法是另一个方法的重载 7 * 方法覆盖(Overriding): 8 * 如果在子类中定义一个方法,其名称、返回类型及参数签名正好与父类中某个方法的名称、返回类型及参数签名相匹配, 9 * 那么可以说,子类的方法覆盖了父类的方法 10 */ 11 public class FunctionCover { 12 public static void main(String[] args){ 13 Figure f = new Figure(10, 10); 14 Rectangle r = new Rectangle(9, 5); 15 Figure figure; 16 figure = f; 17 System.out.println("Area is : " + figure.area()); 18 figure = r; 19 System.out.println("Area is : " + figure.area()); 20 } 21 } 22 23 class Figure{ 24 double dim1; 25 double dim2; 26 Figure(double a, double b){ 27 dim1 = a; 28 dim2 = b; 29 } 30 Double area(){ 31 System.out.println("Inside area for figure."); 32 return (dim2 * dim1); 33 } 34 } 35 36 class Rectangle extends Figure{ 37 Rectangle(double a, double b){ 38 super(a, b); 39 } 40 Double area(){ 41 System.out.println("Inside area for rectangle."); 42 return (dim1 * dim2); 43 } 44 }
(7)方法重载
1 package JavaEE.JavaBaseExampleTest.Functions; 2 3 /** 4 * 方法重载(Overloading)定义: 5 * 如果有两个方法的方法名相同,但参数不一致,哪么可以说一个方法是另一个方法的重载 6 * 7 * 原则: 8 * 1 方法名相同 9 * 2 方法的参数类型,个数顺序至少有一项不同 10 * 3 方法的返回类型可以不相同 11 * 4 方法的修饰符可以不相同 12 * 5 main方法也可以被重载 13 */ 14 public class FunctionLoad { 15 public static void main(String[] args) { 16 MyClass t = new MyClass(3); 17 t.info(); 18 t.info("重载方法\n"); 19 //重载构造函数 20 new MyClass(); 21 } 22 } 23 24 25 class MyClass{ 26 int height; 27 MyClass(){ 28 System.out.println("无参构造函数"); 29 height = 4; 30 } 31 MyClass(int i){ 32 System.out.println("房子高度为:" + i + "米"); 33 height = i; 34 } 35 void info(){ 36 System.out.println("房子高度为 " + height + "米"); 37 } 38 void info(String s){ 39 System.out.println(s + "房子高度为" + height + "米"); 40 } 41 }
(8)汉诺塔
1 package JavaEE.JavaBaseExampleTest.Functions; 2 3 /** 4 * 汉诺塔游戏,玩法如下: 5 * 1 有三根杆子A,B,C 6 * 2 A杆上有若干碟子 7 * 3 每次移动一块碟子,小的只能叠在大的上面 8 * 4 把所有碟子从A杆全部移到 C 杆上 9 */ 10 public class HanNuoTower { 11 public static void main(String[] args) { 12 int nDisks = 3; 13 doTowers(nDisks, 'A', 'B', 'C'); 14 } 15 16 public static void doTowers(int topN, char from, char inter, char to) { 17 if (topN == 1) { 18 System.out.println("Disk 1 from " + from + " to " + to); 19 } else { 20 doTowers(topN - 1, from, to, inter); 21 System.out.println("Disk " + topN + " from " + from + " to " + to); 22 doTowers(topN - 1, inter, from, to); 23 } 24 } 25 }
(9)标签Label
1 package JavaEE.JavaBaseExampleTest.Functions; 2 3 /** 4 * Java 中的标签是为循环设计的,是为了在多重循环中方便的使用break 和 continue 5 */ 6 public class Label { 7 public static void main(String[] args){ 8 String strSearch = "This is the string in which you have to search for a substring."; 9 String subString = "substring"; 10 boolean found = false; 11 int max = strSearch.length() - subString.length(); 12 testLabel: 13 for (int i = 0; i <= max; i++){ 14 int length = subString.length(); 15 int j = i; 16 int k = 0; 17 while (length-- != 0){ 18 if (strSearch.charAt(j++) != subString.charAt(k++)){ 19 continue testLabel; 20 } 21 } 22 found = true; 23 break testLabel; 24 } 25 if(found){ 26 System.out.println("发现子字符串..."); 27 }else { 28 System.out.println("字符串中未发现子字符串..."); 29 } 30 } 31 }
(10)通过重载方法输出不同类型数组
1 package JavaEE.JavaBaseExampleTest.Functions; 2 3 /** 4 * 通过重载 OutputArray 类的 printArray 方法输出不同类型(整型, 双精度及字符型)的数组 5 */ 6 public class OutputArray { 7 public static void printArray(Integer[] inputArray){ 8 for (Integer element:inputArray){ 9 System.out.printf("%s", element); 10 System.out.println(); 11 } 12 } 13 public static void printArray(Double[] inputArray){ 14 for (Double element:inputArray){ 15 System.out.printf("%s", element); 16 System.out.println(); 17 } 18 } 19 public static void printArray(Character[] inputArray){ 20 for (Character element:inputArray){ 21 System.out.printf("%s", element); 22 System.out.println(); 23 } 24 } 25 public static void main(String[] args){ 26 Integer[] interArray = {1, 2, 3, 4, 5}; 27 Double[] doubleArray = {1.1, 2.2, 3.3, 4.4, 5.5}; 28 Character[] charArray = {'J', 'A', 'V', 'A'}; 29 System.out.println("输出整形数组 : "); 30 printArray(interArray); 31 System.out.println("\n输出双精度数组 : "); 32 printArray(doubleArray); 33 System.out.println("\n输出字符数组 : "); 34 printArray(charArray); 35 } 36 37 }
(11)可变参数
1 package JavaEE.JavaBaseExampleTest.Functions; 2 3 /** 4 * 在重载方法中使用可变参数 5 */ 6 public class OvreloadingOfVarargs { 7 static void vaTest(int... no) { 8 System.out.println("vaTest(int...):" + "参数个数:" + no.length + "内容:"); 9 for (int n : no) 10 System.out.print(n + " "); 11 System.out.println(); 12 } 13 14 static void vaTest(boolean... bl) { 15 System.out.println("vaTest(boolean...):" + "参数个数:" + bl.length + "内容:"); 16 for (boolean n : bl) 17 System.out.print(n + " "); 18 System.out.println(); 19 } 20 21 static void vaTest(String msg, int... no) { 22 System.out.println("vaTest(String, int...):" + msg + "参数个数:" + no.length + "内容:"); 23 for (int n : no) 24 System.out.print(n + " "); 25 System.out.println(); 26 } 27 28 public static void main(String[] args) { 29 vaTest(1, 2, 3); 30 vaTest("测试", 10, 20); 31 vaTest(true, false, false); 32 } 33 }
(12)实参个数可变
1 package JavaEE.JavaBaseExampleTest.Functions; 2 3 /** 4 * 定义实参个数可变的方法:只要在一个形参的"类型"与"参数名"之间加上三个连续的"." 5 * (即"...",英文里的句中省略号),就可以让它和不确定个实参相匹配 6 */ 7 public class Varargs { 8 static int sumVarargs(int... intArrays){ 9 int sum,i; 10 sum = 0; 11 for (i = 0; i < intArrays.length; i++){ 12 sum += intArrays[i]; 13 } 14 return (sum); 15 } 16 public static void main(String[] args){ 17 int sum = 0; 18 sum = sumVarargs(new int[]{10, 12, 33, 45}); 19 System.out.println("数字相加之和 :" + sum); 20 } 21 }