面向对象：oop object oriented proogramming
面向对象特征：封装继承多态 类与对象的关系：类是抽象的，对象是类的实例 类是由类得成员组成(成员变量，成员方法）； 默认初始化，少不了。
类的定义
Public class className{} 对于基本数据类型中的布尔类型，getter方法用isMale This写在方法里，谁调用谁就是this 构造方法，专门来创造对象的方法 注意事项 必须和类名大小写一样 3. 不要返回值类型 4. 构造方法不能返回值 5. 如果没有构造方法 系统会赠送一个构造方法 6. 一旦编写一个构造方法系统将不会赠送。
例子 一个学生类
package student.java;
public class Person {
//成员变量
private int age;
private String name;
private String school;
private String major;
//有参构造
public Person(int age, String name, String school, String major) {
super();
this.age = age;
this.name = name;
this.school = school;
this.major = major;
}
//因为属性私有，只能本类访问，所以加入gettersetter方法方便其他的类调用
public String getSchool() {
return school;
}
public void setSchool(String school) {
this.school = school;
}
public String getMajor() {
return major;
}
public void setMajor(String major) {
this.major = major;
}
//构造方法重载
public Person(int age, String name,String school) {
this.name=name;
this.age=age;
this.school=school;
}
public Person(int age, String name) {
this.age = age;
this.name = name;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
if(age>0&&age<130){
this.age = age;
}else{
System.out.println("输入年龄有误");
}
}
}
类的实例化—创建对象
package student.java;
public class PersonTest {
public static void main(String[] args) {
// TODO Auto-generated method stub
/*
* Person p1=new Person(18,"hcl");
*
* System.out.println(p1.getAge()+p1.getName());
* System.out.println("================"); Person p2=new Person();
* p2.setAge(18); p2.setName("smz");
* System.out.println(p2.getAge()+p2.getName());
*/
Person p1 = new Person(18, "hcl");
System.out.println("age: "+p1.getAge()+" name: "+p1.getName());
System.out.println("============================================");
Person p2 = new Person(18, "hcl", "梵蒂冈");
System.out.println("age: "+p2.getAge()+" name: "+p2.getName()+" school: "+p2.getSchool());
System.out.println("============================================");
Person p3 = new Person(18, "hcl", "梵帝高", "计算机科学与技术（软件开发）");
System.out.println("age: "+p3.getAge()+" name: "+p3.getName()+" school: "+p3.getSchool()+" major: "+p3.getMajor());
System.out.println("============================================");
p3.setAge(21);
System.out.println("age: "+p3.getAge()+" name: "+p3.getName()+" school: "+p3.getSchool()+" major: "+p3.getMajor());
}
}
