ArrayList集合 本质上相当于长度可变数组，所以用法有相似之处。
package collection;
import java.util.ArrayList;
class Dog{
private String name;
private String sex;
public Dog() {
super();
}
public Dog(String name, String sex) {
super();
this.name = name;
this.sex = sex;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getSex() {
return sex;
}
public void setSex(String sex) {
this.sex = sex;
}
}
public class ArrayLi {
public static void main(String[] args) {
ArrayList list = new ArrayList();
Dog dog1 = new Dog("jerry","female");
Dog dog2 =new Dog("tom","male");
list.add(dog1);//添加对象
list.add(0, dog2);
list.add(new Dog("lucy","female"));
System.out.println("删除之前有"+list.size()+"条狗狗");
Dog dog[] = new Dog[3] ;
dog[0]= (Dog)list.get(0);//获取对象
dog[1] = (Dog)list.get(1);
dog[2] = (Dog)list.get(2);
for (Dog dg : dog) {
System.out.println("我的名字是"+dg.getName());
}
Dog g = (Dog)list.remove(0);
System.out.println("删除的狗狗是"+g.getName());
System.out.println(list.remove(dog2));//因为dog1已被删除，所以结果为false
System.out.println(list.remove(dog1));//true
System.out.println("删除之后有"+list.size()+"条狗狗");
for(int i = 0;i Dog dg = (Dog)list.get(i);//获取对象 System.out.println("我的名字是"+dg.getName()); } } } 参考于在线api（Collection接口） package collection; import java.util.ArrayList; import java.util.Collection; import java.util.Iterator; public class Demo1 { public static void main(String[] args) { Collection col = new ArrayList(); Collection col2 = new ArrayList(); //Collection为接口所以col调用的所有方法 //皆为ArrayList类中的实现Collection接口中的方法 System.out.println(col);//结果:[] //col自动调了col.toString()方法进行了转换 //所以输出的不是地址 System.out.println("------------------"); col.add("tom"); col.add("tom"); System.out.println(col); //结果：[tom, tom] col2.addAll(col); System.out.println(col2); //结果：[tom, tom] col2.clear(); System.out.println("------------------"); System.out.println(col2);//结果:[] System.out.println(col.contains("tom"));//结果:true System.out.println(col.equals(col2));//结果：false col2.addAll(col); System.out.println(col.equals("tom"));//结果：false System.out.println(col.equals(col2));//结果：true Object[] a = col.toArray(); System.out.println(a);//地址 System.out.println(a[0]);//tom System.out.println(a[1]);//tom Iterator ite = col.iterator(); while(ite.hasNext()){ System.out.print(ite.next());//tomtom } int size = col.size(); System.out.println(size);//2 } }
