java集合的概念与Collection体系
概念:对象的容器,实现了对象的常用操作,类似数组功能,长度不固定,只能存储引用类型。
Collction特点:无序,无下标
集合添加学生类代码
//学生类
package qianfeng;
public class Student {
private int age;
private String name;
public Student(int age, String name) {
super();
this.age = age;
this.name = name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
@Override
public String toString() {
return "Student [age=" + age + ", name=" + name + "]";
}
private int age;
private String name;
public Student(int age, String name) {
super();
this.age = age;
this.name = name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
@Override
public String toString() {
return "Student [age=" + age + ", name=" + name + "]";
}
}
**************************
测试类
public class Demo4 {
public static void main(String[] args) {
// TODO Auto-generated method stub
Collection cl=new ArrayList();//声明集合
Student s1=new Student(19,"ZG");//实例化学生类
Student s2=new Student(12,"FE");
Student s3=new Student(22,"KG");
cl.add(s1);
cl.add(s2);
cl.add(s3);
// cl.clear();清空集合,实例化的对象不消失
System.out.println(cl.size());
Iterator it=cl.iterator();
while(it.hasNext()) {//如果他又下个值
Object ob=it.next();
System.out.println(ob);
}
}
// TODO Auto-generated method stub
Collection cl=new ArrayList();//声明集合
Student s1=new Student(19,"ZG");//实例化学生类
Student s2=new Student(12,"FE");
Student s3=new Student(22,"KG");
cl.add(s1);
cl.add(s2);
cl.add(s3);
// cl.clear();清空集合,实例化的对象不消失
System.out.println(cl.size());
Iterator it=cl.iterator();
while(it.hasNext()) {//如果他又下个值
Object ob=it.next();
System.out.println(ob);
}
}
}