package ch6;

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;

public class TestEx {

	public static void main(String[] args){ // part5 main方法抛出异常 throws Exception,实际编程中不要写。
		// Part 1:异常出现示例
		int [] arr = {1, 2, 3};
		System.out.println(arr[3]);
		
		
		//System.out.println(2/0);
		
		/*try { 
			System.out.println(2/0);
		} catch(ArithmeticException ae) {
			System.out.println("系统正在维护中,请与管理员联系"); // good or not
			// ae.printStackTrace();
		}*/
		
		// Part 2:抛出异常示例
		/*TestEx ex = new TestEx();
		ex.m(0);*/
		
		/*try {
			new TextEx().m(0);
		} catch(ArithmeticException e ) {
			System.out.println("出错了");
		}*/
		
		
		// Part 3: 必须处理的异常继承于Exception
		/*
		FileInputStream in = null;
		try {
			in = new FileInputStream("test.txt");
			int b;
			b = in.read();
			while(b != -1) {
				System.out.print(b);
				b = in.read();
			}
		} catch (FileNotFoundException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		} finally {
			try {
				in.close();
			} catch (IOException e) {
				e.printStackTrace();
			}
		} */
		
		// Part 4: try-catch-finally关系
		TestEx te = new TestEx();
		try {
			new TestEx().f2();
		} catch(FileNotFoundException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		}
	}

	public void m(int n) throws ArithmeticException {
		if (n == 0) {
			throw new ArithmeticException("被除数为0");
		}
	}

	void f() throws FileNotFoundException, IOException {
		FileInputStream in = new FileInputStream("test.txt");
		int b;
		b = in.read();
		while( b != -1) {
			System.out.println((char)b);
			b = in.read();
		}
	}
	
	void f2() throws FileNotFoundException, IOException { //处理,或者继续抛出
		f();
	}
}