public class HelloWorld { /* 第一個Java程序 * 它將輸出字符串 Hello World */ public static void main(String[] args) { System.out.println("Hello World"); // 輸出 Hello World } }
class FreshJuice { enum FreshJuiceSize{ SMALL, MEDIUM , LARGE } FreshJuiceSize size; } public class FreshJuiceTest { public static void main(String[] args){ FreshJuice juice = new FreshJuice(); juice.size = FreshJuice.FreshJuiceSize.MEDIUM ; } }
1 public class Puppy{ 2 int puppyAge; 3 public Puppy(String name){ 4 // 這個構造器僅有一個參數:name 5 System.out.println("小狗的名字是 : " + name ); 6 } 7 8 public void setAge( int age ){ 9 puppyAge = age; 10 } 11 12 public int getAge( ){ 13 System.out.println("小狗的年齡為 : " + puppyAge ); 14 return puppyAge; 15 } 16 17 public static void main(String[] args){ 18 /* 創建對象 */ 19 Puppy myPuppy = new Puppy( "tommy" ); 20 /* 通過方法來設定age */ 21 myPuppy.setAge( 2 ); 22 /* 調用另一個方法獲取age */ 23 myPuppy.getAge( ); 24 /*你也可以像下面這樣訪問成員變量 */ 25 System.out.println("變量值 : " + myPuppy.puppyAge ); 26 } 27 }
1 import java.io.*; 2 3 public class Employee{ 4 String name; 5 int age; 6 String designation; 7 double salary; 8 // Employee 類的構造器 9 public Employee(String name){ 10 this.name = name; 11 } 12 // 設置age的值 13 public void empAge(int empAge){ 14 age = empAge; 15 } 16 /* 設置designation的值*/ 17 public void empDesignation(String empDesig){ 18 designation = empDesig; 19 } 20 /* 設置salary的值*/ 21 public void empSalary(double empSalary){ 22 salary = empSalary; 23 } 24 /* 打印信息 */ 25 public void printEmployee(){ 26 System.out.println("名字:"+ name ); 27 System.out.println("年齡:" + age ); 28 System.out.println("職位:" + designation ); 29 System.out.println("薪水:" + salary); 30 } 31 }
1 import java.io.*; 2 public class EmployeeTest{ 3 4 public static void main(String[] args){ 5 /* 使用構造器創建兩個對象 */ 6 Employee empOne = new Employee("RUNOOB1"); 7 Employee empTwo = new Employee("RUNOOB2"); 8 9 // 調用這兩個對象的成員方法 10 empOne.empAge(26); 11 empOne.empDesignation("高級程序員"); 12 empOne.empSalary(1000); 13 empOne.printEmployee(); 14 15 empTwo.empAge(21); 16 empTwo.empDesignation("菜鳥程序員"); 17 empTwo.empSalary(500); 18 empTwo.printEmployee(); 19 } 20 }