throwtest.java

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import java.io.*;
class ThrowTest
{
	//定义throwTest1()方法，并抛出ArithmeticException异常
	public void throwTest1() throws ArithmeticException
	{
		//方法中输出3/0的值，会出现异常
		System.out.println(3/0);
	}
    //定义throwTest2()方法，并抛出ArrayIndexOutOfBoundsException异常
	public void throwTest2() throws ArrayIndexOutOfBoundsException
	{
		int a[] = {1,2};
		//方法中输出数组a[2]的值，由于数组只包含a[0]=1,a[1]=2两个元素，所以出现异常
		System.out.println(a[2]);
	}
    //定义throwTest3()方法，并抛出FileNotFoundException异常
	public void throwTest3() throws FileNotFoundException
	{
		File file = new File("abc.txt");
		//方法中打开文件使用BufferedReader类打开文件，由于文件不存在出现异常
		new BufferedReader(new FileReader(file));
	}
    //定义throwTest4()方法，并抛出FileNotFoundException异常
	public void throwTest4() throws FileNotFoundException
	{
		//直接用throw语句抛出FileNotFoundException异常
		throw new FileNotFoundException("abc.txt");
	}	
	public static void main(String argv[])
	{
		ThrowTest throwTest = new ThrowTest();
		//调用抛出算术异常的方法throwTest1()，并捕获处理异常
		try             //检查是否出现异常
		{
			throwTest.throwTest1();  
		}
		catch(ArithmeticException e1)   //捕捉异常
		{
	    	System.out.print("3/0: " );
	    	System.out.println("This is ArithmeticException");
		}
        //调用抛出数组越界异常的方法throwTest2()，并捕获处理异常
		try     //检查是否出现异常
		{
			throwTest.throwTest2();
		}
		catch(ArrayIndexOutOfBoundsException e2)  //捕捉异常
		{
	    	System.out.print("a[2] is out of Array: " );
	    	System.out.println("This is ArrayIndexOutOfBoundsException");
		}
		//调用抛出I/O异常的方法throwTest3()，并捕获处理异常
		try    //检查是否出现异常
		{
			throwTest.throwTest3();
		}
		catch(FileNotFoundException e3)   //捕捉异常
		{
	    	System.out.print("abc.txt is not found: " );
	    	System.out.println("This is FileNotFoundException");
		}
        //调用抛出I/O异常的方法throwTest4()，并捕获处理异常
		try    //检查是否出现异常
		{
			throwTest.throwTest4();
		}
		catch(FileNotFoundException e4)    //捕捉异常
		{
	    	System.out.print("abc.txt is not found: " );
	    	System.out.println("This is FileNotFoundException");
		}
	}
}