1. 程式人生 > >11-10 動手動腦

11-10 動手動腦

AboutException.java
package main;

import javax.swing.*;

public class AboutException {
   public static void main(String[] a) 
   {
      int i=1, j=0, k;
      k=i/j;


    try
    {
        
        k = i/j;    // Causes division-by-zero exception
        //throw new Exception("Hello.Exception!");
    }
    
    
catch ( ArithmeticException e) { System.out.println("被0除. "+ e.getMessage()); } catch (Exception e) { if (e instanceof ArithmeticException) System.out.println("被0除"); else { System.out.println(e.getMessage()); } }
finally { JOptionPane.showConfirmDialog(null,"OK"); } } }

 

CatchWho 。Java
public class CatchWho { 
    public static void main(String[] args) { 
        try { 
                try { 
                    throw new ArrayIndexOutOfBoundsException(); 
                } 
                
catch(ArrayIndexOutOfBoundsException e) { System.out.println( "ArrayIndexOutOfBoundsException" + "/內層try-catch"); } throw new ArithmeticException(); } catch(ArithmeticException e) { System.out.println("發生ArithmeticException"); } catch(ArrayIndexOutOfBoundsException e) { System.out.println( "ArrayIndexOutOfBoundsException" + "/外層try-catch"); } }

CatchWho2。Java

public class CatchWho2 { 
    public static void main(String[] args) { 
        try {
                try { 
                    throw new ArrayIndexOutOfBoundsException(); 
                } 
                catch(ArithmeticException e) { 
                    System.out.println( "ArrayIndexOutOfBoundsException" + "/內層try-catch"); 
                }
            throw new ArithmeticException(); 
        } 
        catch(ArithmeticException e) { 
            System.out.println("發生ArithmeticException"); 
        } 
        catch(ArrayIndexOutOfBoundsException e) { 
            System.out.println( "ArrayIndexOutOfBoundsException" + "/外層try-catch"); 
        } 
    } 

EmbededFinally。Java

public class EmbededFinally {

    
    public static void main(String args[]) {
        
        int result;
        
        try {
            
            System.out.println("in Level 1");

           
             try {
                
                System.out.println("in Level 2");
  // result=100/0;  //Level 2
               
                 try {
                   
                     System.out.println("in Level 3");
                      
                     result=100/0;  //Level 3
                
                } 
                
                catch (Exception e) {
                    
                    System.out.println("Level 3:" + e.getClass().toString());
                
                }
                
                
                finally {
                    
                    System.out.println("In Level 3 finally");
                
                }
                
               
                // result=100/0;  //Level 2

            
                }
            
            catch (Exception e) {
               
                 System.out.println("Level 2:" + e.getClass().toString());
           
             }
             finally {
                
                System.out.println("In Level 2 finally");
           
             }
             
            // result = 100 / 0;  //level 1
        
        } 
        
        catch (Exception e) {
            
            System.out.println("Level 1:" + e.getClass().toString());
        
        }
        
        finally {
           
.             System.out.println("In Level 1 finally");
        
        }
    
    }

}

SystemExitAndFinally.java

public class SystemExitAndFinally {

    
    public static void main(String[] args)
    {
        
        try{

            
            System.out.println("in main");
            
            throw new Exception("Exception is thrown in main");

                    //System.exit(0);

        
        }
        
        catch(Exception e)

            {
            
            System.out.println(e.getMessage());
            
            System.exit(0);
        
        }
        
        finally
        
        {
            
            System.out.println("in finally");
        
        }
    
    }


}

PrintExpressionStack.java
// UsingExceptions.java
// Demonstrating the getMessage and printStackTrace
// methods inherited into all exception classes.
public class PrintExceptionStack {
   public static void main( String args[] )
   {
      try {
         method1();
      }
      catch ( Exception e ) {
         System.err.println( e.getMessage() + "\n" );
         e.printStackTrace();
      }
   }

   public static void method1() throws Exception
   {
      method2();
   }

   public static void method2() throws Exception
   {
      method3();
   }

   public static void method3() throws Exception
   {
      throw new Exception( "Exception thrown in method3" );
   }
}

ThrowMultiExceptionsDemo.java
import java.io.*;
public class ThrowMultiExceptionsDemo { 
    public static void main(String[] args) 
        { 
      try { 
            throwsTest(); 
       } 
        catch(IOException e) { 
            System.out.println("捕捉異常"); 
        }
    }

    private static void throwsTest()  throws ArithmeticException,IOException { 
        System.out.println("這只是一個測試"); 
        // 程式處理過程假設發生異常
        throw new IOException(); 
        //throw new ArithmeticException(); 
    } 
}

OverrideThrows.java

import java.io.*;


public class OverrideThrows
{
    public void test()throws IOException
    {
        FileInputStream fis = new FileInputStream("a.txt");
    }
}
class Sub extends OverrideThrows
{
    //如果test方法宣告丟擲了比父類方法更大的異常,比如Exception
    //則程式碼將無法編譯……
    public void test() throws FileNotFoundException
    {
            //...
    }
}

ExceptionLinkInRealWorld.java
/**
 * 自定義的異常類
 * @author JinXuLiang
 *
 */
class MyException extends Exception
{
    public MyException(String Message) {
        super(Message);
    }
    public MyException(String message, Throwable cause) {
        super(message, cause);
    }
     public MyException( Throwable cause) {
        super(cause);
    }

}

public class ExceptionLinkInRealWorld {
   public static void main( String args[] )
   {
      try {
         throwExceptionMethod();  //有可能丟擲異常的方法呼叫
      }
      catch ( MyException e )
      {
         System.err.println( e.getMessage() );
         System.err.println(e.getCause().getMessage());
      }
      catch ( Exception e )
      {
         System.err.println( "Exception handled in main" );
      }
      doesNotThrowException(); //不丟擲異常的方法呼叫
   }

   public static void throwExceptionMethod() throws MyException
   {
      
      try {
         System.out.println( "Method throwException" );

         throw new Exception("系統執行時引發的特定的異常");  // 產生了一個特定的異常
      }
      catch( Exception e )
      {
         System.err.println(
            "Exception handled in method throwException" );
         //轉換為一個自定義異常,再丟擲
         throw new MyException("在方法執行時出現異常",e);

         
      }
      finally {
         System.err.println(
            "Finally executed in throwException" );
      }

      // any code here would not be reached
   }

   public static void doesNotThrowException()
   {
      try {
         System.out.println( "Method doesNotThrowException" );
      }
      catch( Exception e )
      {
         System.err.println( e.toString() );
      }
      finally {
         System.err.println(
            "Finally executed in doesNotThrowException" );
      }

      System.out.println(
         "End of method doesNotThrowException" );
   }
}