1 package zl_ObjectTest1; 2  3 public class Animal { 4  5 private String name; 6 private String Color; 7 private int age; 8  9 10 public Animal() {11 super();12 13 }14 15 16 17 18 public Animal(String name, String color, int age) {19 super();20 this.name = name;21 Color = color;22 this.age = age;23 }24 25  26 27 28 public String getName() {29 return name;30 }31 public void setName(String name) {32 this.name = name;33 }34 public String getColor() {35 return Color;36 }37 public void setColor(String color) {38 Color = color;39 }40 public int getAge() {41 return age;42 }43 public void setAge(int age) {44 this.age = age;45 }46 47  48 49 50 public String toString() {51 return "Animal [name=" + name + ", Color=" + Color + ", age=" + age52 + "]";53 }54 }

 1 package zl_ObjectTest1; 2  3 import java.util.ArrayList; 4 import java.util.Collection; 5  6  7 public class AnimalCollection { 8  9 public static void main(String[] args) {10 11 // 创建集合对象12 Collection animal = new ArrayList();13 14 // 创建集合对象15 Animal a1 = new Animal("猫", "虎纹", 2);16 Animal a2 = new Animal("荷兰猪", "粉色", 1);17 Animal a3 = new Animal("老鹰", "黑白", 4);18 Animal a4 = new Animal("鹦鹉", "五颜六色", 2);19 Animal a5 = new Animal("警犬", "黑色", 3);20 21 // 把动物对象添加进集合中22 // animal.add(a1); /这里进行了一次向上转型 Object abj = "a1";23 animal.add(a2);24 animal.add(a3);25 animal.add(a4);26 animal.add(a5);27 28 // 把集合转换成数组29 // Object[] toArray():把集合转成数组，可以实现集合的遍历30 31 Object[] abj = animal.toArray();32 33 // 遍历数组34 for (int x = 0; x < abj.length; x++) {35 // System.out.println(abj[x]);//这个打印出来的是地址值36 37 // 要进行次向下转型 ,这样就可以调用Animal里面的方法38 Animal s = (Animal) abj[x];39 System.out.println(s);// 这样调用的是Animal里面的toStrin()40 // 自己调用想要显示的格式41 System.out.println("种类：" + s.getName() + "\t颜色：" + s.getColor()42 + "\t年龄：" + s.getAge());43 }44 45 }46 47 }