class Telphone{ private float screen=5.0f; private float cpu=1.4f; private float mem=2.0f; public float getScreen(){ return screen; } public float setScreen(float newScreen){ screen=newScreen; }
//其他getter/setter方法 }
蓝色体为访问修饰符
作用：可修饰属性和方法的访问范围
同包：指在一个路径下
访问修饰符 本类 同包 子类 其他
private √
默认 √ √
protected √ √ √
public √ √ √ √
class Telphone{
private float screen; //若将“private”改为“public”，
private float cpu;
private float mem;
public void sendMessage(){
System.out.println("sendMessage");
}
public float getScreen(){
return screen;
}
public void setScreen(float screen){
this.screen=screen; //为了区分属性和参数名，所以在参数名前+this,意思为：将参数的值赋给当前对象的属性
this.sendMessage(); //调用当前对象的方法
}
public float getCpu(){
return cpu;
}
public void setCpu(float cpu){
this.cpu=cpu;
}
public float getMem(){
return mem;
}
public void setMem(float mem){
this.mem=mem;
}
public Telphone(){
System.out.println("无参的构造方法执行了");
}
public Telphone(float newScreen,float newCpu,float newMem){
if(newScreen<3.5f){
System.out.println("输入的数据错误");
screen=3.5f;
}
cpu=newCpu;
mem=newMem;
System.out.println("有参的构造方法执行了");
}
}
class Ex17{
public static void main(String[] args){
Telphone phone2=new Telphone(1.5f,1.4f,2.0f);
//若将“private”改为“public”，则在此添加 “phone2.screen=6.0f;” 不会报错
System.out.println("screen:"+phone2.getScreen());
}
}