第 1 关:Java 中的异常处理机制
1.在 Java 中,源文件 Test.java 中包含如下代码段,则程序编译运行结果是( )
答案:b
2.下列关于检测性异常和非检测性异常正确的是( )
A、IOException及其子类(FileNotFoundException等),都属于检测型异常
答案:ace
3.关于下列代码,说法正确的是()
答案:d
第二关 捕获异常
package step2;import java.util.Scanner;public class Task {public static void main(String[] args) {Scanner sc = new Scanner(System.in);int num1 = sc.nextInt();int num2 = sc.nextInt();try{System.out.println(num1/num2);}catch(ArithmeticException e){System.out.print("除数不能为0");}}}
第 3 关:抛出异常
package step3;import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;public class Task {public static void main(String[] args)throws FileNotFoundException { test();}public static void test() throws FileNotFoundException {File file = new File("abc");if(!file.exists()){ throw new FileNotFoundException("该文件不存在");}else{FileInputStream fs = new FileInputStream(file);}}
}
第 4 关:自定义异常
package step4;import java.util.Scanner;public class Task {
public static void main(String[] args) throws MyException {
Scanner sc = new Scanner(System.in);
String username = sc.next();
if(username.length()❤️){
throw new MyException(“用户名小于三位Exception”);}System.out.println("用户名格式正确");
}
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2
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}class MyException extends Exception{
public MyException(){
}
public MyException(String msg)
{
super(msg);
}
}