Java异常

1.throw和throws

    private static void printArr(int[] arr){
        if (arr == null){
            throw new NullPointerException();
        } else {
            for (int i = 0; i < arr.length; i++) {
                System.out.print(arr[i] + " ");
            }
        }
    }

public void myMethod() throws IOException {
    // 可能会引发IOException的代码
}

2.try catch

        try {
            Scanner sc = new Scanner(System.in);
            System.out.println("请输入你的年纪:");
            String name = sc.nextLine();
            int age =Integer.parseInt(name);
            System.out.println(name);
            System.out.println(2/0);
        } catch (NumberFormatException e) {
            System.out.println("解析错误发生了");
        } catch (ArithmeticException e){
            System.out.println("数学运算错误发生了");
        }
        System.out.println("嘿嘿嘿 我是最帅的!");

3.Throwable的成员方法

public String getMessage() //返回此throwable的详细消息字符串

    public static void main(String[] args) {
        int[] arr = new int[] { 1, 2, 3, 4, 5 };
        try {
            System.out.println(arr[10]);
        } catch (ArrayIndexOutOfBoundsException e){
            System.out.println(e.getMessage());
        }
    }
//结果是:  Index 10 out of bounds for length 5

public String toString()//返回此可抛出的简短描述

    public static void main(String[] args) {
        int[] arr = new int[] { 1, 2, 3, 4, 5 };
        try {
            System.out.println(arr[10]);
        } catch (ArrayIndexOutOfBoundsException e){
            System.out.println(e.toString());
        }
    }
//结果: java.lang.ArrayIndexOutOfBoundsException: Index 10 out of bounds for length 5

public void printStackTrace() //把异常的错误信息输出在控制台(字体是红色的)

    public static void main(String[] args) {
        int[] arr = new int[] { 1, 2, 3, 4, 5 };
        try {
            System.out.println(arr[10]);
        } catch (ArrayIndexOutOfBoundsException e){
            e.printStackTrace();
        }
        System.out.println("我的牛牛很大");
    }
/*运行结果:
D:\JavaDevelop\Java\java17\bin\java.exe "-javaagent:D:\JavaDevelop\idea\IntelliJ IDEA 2024.1.4\lib\idea_rt.jar=51228:D:\JavaDevelop\idea\IntelliJ IDEA 2024.1.4\bin" -Dfile.encoding=UTF-8 -classpath D:\JavaWorkSpace\xing-xi-guan-li\out\production\ExceptionDemo1 ExceptionDemo1.ExceptionDemo1
java.lang.ArrayIndexOutOfBoundsException: Index 10 out of bounds for length 5
    at ExceptionDemo1.ExceptionDemo1.main(ExceptionDemo1.java:9)
我的牛牛很大
*/