在java中，throw与throws有什么区别
1、throw是在代码块内的，即在捕获方法内的异常并抛出时用的；
2、throws是针对方法的，即将方法的异常信息抛出去
3、可以理解为throw是主动（在方法内容里我们是主动捕获并throw的），而throws是被动（在方法上是没有捕获异常进行处理，直接throws的）
4、例子：
public void str2int(String str) throws Exception { //这里将得到的异常向外抛出
try {
System.out.println(Integer.parseInt(str));
} catch(NumberFormatException e) {
//TODO 这里可以做一些处理，处理完成后将异常报出，让外层可以得到异常信息
throw new Exception("格式化异常");
}
}
throw用于方法体中，抛出某种类型的异常。
上代码：
public void fun() throws Exception {
try {
...
if (boolean) {
...
} else {
throw new MyException();
}
} catch (Exception e) {
...
throw e;
} finally {
... ...
]
}
前者说你会扔某些异常。 后者是你真的扔某异常
package practice;
public class pracrice_1 {
public static void main(String[] args) {
Vehicle vehicle = new Vehicle(4,5);
Vehicle car=new Car(4, 3, 4);
Vehicle truck = new Truck(4,3,4,5);
vehicle.showInfo();
car.showInfo();
truck.showInfo();
System.out.println(Integer.BYTES);
}
}
class Vehicle{
private int wheels;
private int weight;
public Vehicle(int wheels,int weight) {
this.weight=weight;
this.setWheels(wheels);
}
void showInfo(){
System.out.println("车轮个数为："+this.getWheels()+"车重为："+this.weight);
}
public int getWheels() {
return wheels;
}
public void setWheels(int wheels) {
this.wheels = wheels;
}
public int getWeight() {
return weight;
}
public void setWeight(int weight) {
this.weight = weight;
}
}
class Car extends Vehicle{
int loader;
public Car(int wheels,int weight,int loader) {
super(wheels,weight);
this.loader=loader;
}
void showInfo() {
System.out.println("车轮个数为："+super.getWheels()+"车重为："+this.getWeight()+"载人数为"+this.loader);
}
public int getloader() {
return loader;
}
public void setloader(int loader) {
this.loader = loader;
}
}
class Truck extends Car{
private int payload;
public Truck(int wheels, int weight, int loader,int payload) {
super(wheels, weight, loader);
this.payload=payload;
}
@Override
void showInfo() {
System.out.println("车轮个数为："+super.getWheels()+"车重为："+this.getWeight()+"载人数为"+this.loader+"载重量："+this.payload);
}
}
建议你这样试试看：
这样做的好处：
注意事项：
