1，常见异常

• ArrayIndexOutOfBoundsException,数组下标越界异常
• NullPointerException,空指针异常
• ArithmeticException,算术异常
• ClassCastException,类型转换异常

2，throws与throw

• throws在方法声明处，throw在方法中
• throws后面跟异常类名，throw后跟异常对象
• throws是处理异常，throw是手动产生异常

package ExceptionDemo;
/*
 * 处理异常的两种方式
 * throws抛出异常，try/catch手动捕捉异常
 * throw是手动产生异常
 */
public class ThrowAndThrows {
    public static void main(String[] args) {
        show();
    }
public static void show(){
    int i = 10;
    int b = 2;
    int c = i/b;
    if (b == 2) {
        try {
            throw new Exception();//认为添加异常
        } catch (Exception e) {
            // TODO: handle exception
            System.out.println("b不能为2");
        }
    }
}
}

3，手动抛出自定义异常

package ExceptionDemo;

public class CustomDemo {

    public static void main(String[] args) {
        int a=10;
        if (a==10) {
            try {
                throw new Custom1("a不能为10");//手动抛出自定义异常
            } catch (Custom1 e) {
                e.printStackTrace();
            }
        }
    }
}
class Custom1 extends Exception{
    public Custom1(String message) {
        //将信息传递给Exception
        super(message);
    }
}