70 lines
1.9 KiB
Java
70 lines
1.9 KiB
Java
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// 当出现继承关系时，异常处理中要注意下面三中情况：
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// * A:子类重写父类方法时，子类的方法必须抛出相同的异常或父类异常的子类。
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// * B:如果父类抛出了多个异常,子类重写父类时，只能抛出相同的异常或者是他的子集，子类不能抛出父类没有的异常
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// * C:如果被重写的方法没有异常抛出，那么子类的方法绝对不可以抛出异常，如果子类方法内有异常发生，那么子类只能try，不能throws。
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// 请在下面代码的基础上，通过增加、修改代码对上面三种情况进行测试。
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package exp9;
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import java.io.FileReader;
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import java.io.IOException;
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import java.text.ParseException;
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import java.text.SimpleDateFormat;
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import java.util.Date;
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public class ExceptionDemo {
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public static void main(String[] args) {
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Fu o = new Zi();
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try{
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o.show();
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o.method2();
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o.method();
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}catch(Exception e){
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}
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}
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}
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class Fu {
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public void show() throws Exception {
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}
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public void method() {
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}
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public void method2() throws Exception{
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}
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}
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class Zi extends Fu {
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@Override
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// public void show() throws Exception{
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// [* A]
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public void show() throws ArithmeticException {
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System.out.println(1/0);
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}
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@Override
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//[* B]
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public void method2() throws IOException, ArrayIndexOutOfBoundsException/*, RuntimeException*/{
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new FileReader("NotExistFile").close();
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int[] arr = new int[3];
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System.out.println(arr[5]);
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}
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//测试throws和try方法
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// [* C]
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@Override
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public void method()/*throws ParseException*/{
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try{
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String s = "2014-11-20";
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SimpleDateFormat sdf = new SimpleDateFormat();
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Date d = sdf.parse(s);
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System.out.println(d);
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}catch(ParseException e){
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System.out.println("解析日期格式失败!");
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}
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}
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}
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