吴裕雄--天生自然 JAVA开发学习：异常处理

Posted 2021-12-18 tszr

try

   // 程序代码
catch(ExceptionName e1)

   //Catch 块

import java.io.*;
public class ExcepTest
 
   public static void main(String args[])
      try
         int a[] = new int[2];
         System.out.println("Access element three :" + a[3]);
      catch(ArrayIndexOutOfBoundsException e)
         System.out.println("Exception thrown  :" + e);
      
      System.out.println("Out of the block");
   

try
   // 程序代码
catch(异常类型1 异常的变量名1)
  // 程序代码
catch(异常类型2 异常的变量名2)
  // 程序代码
catch(异常类型2 异常的变量名2)
  // 程序代码

try 
    file = new FileInputStream(fileName);
    x = (byte) file.read();
 catch(FileNotFoundException f)  // Not valid!
    f.printStackTrace();
    return -1;
 catch(IOException i) 
    i.printStackTrace();
    return -1;

import java.io.*;
public class className

  public void deposit(double amount) throws RemoteException
  
    // Method implementation
    throw new RemoteException();
  
  //Remainder of class definition

import java.io.*;
public class className

   public void withdraw(double amount) throws RemoteException,
                              InsufficientFundsException
   
       // Method implementation
   
   //Remainder of class definition

try
  // 程序代码
catch(异常类型1 异常的变量名1)
  // 程序代码
catch(异常类型2 异常的变量名2)
  // 程序代码
finally
  // 程序代码

public class ExcepTest
  public static void main(String args[])
    int a[] = new int[2];
    try
       System.out.println("Access element three :" + a[3]);
    catch(ArrayIndexOutOfBoundsException e)
       System.out.println("Exception thrown  :" + e);
    
    finally
       a[0] = 6;
       System.out.println("First element value: " +a[0]);
       System.out.println("The finally statement is executed");
    
  

class MyException extends Exception

import java.io.*;
 
//自定义异常类，继承Exception类
public class InsufficientFundsException extends Exception

  //此处的amount用来储存当出现异常（取出钱多于余额时）所缺乏的钱
  private double amount;
  public InsufficientFundsException(double amount)
  
    this.amount = amount;
   
  public double getAmount()
  
    return amount;
  

import java.io.*;
 
//此类模拟银行账户
public class CheckingAccount

  //balance为余额，number为卡号
   private double balance;
   private int number;
   public CheckingAccount(int number)
   
      this.number = number;
   
  //方法：存钱
   public void deposit(double amount)
   
      balance += amount;
   
  //方法：取钱
   public void withdraw(double amount) throws
                              InsufficientFundsException
   
      if(amount <= balance)
      
         balance -= amount;
      
      else
      
         double needs = amount - balance;
         throw new InsufficientFundsException(needs);
      
   
  //方法：返回余额
   public double getBalance()
   
      return balance;
   
  //方法：返回卡号
   public int getNumber()
   
      return number;
   

public class BankDemo

   public static void main(String [] args)
   
      CheckingAccount c = new CheckingAccount(101);
      System.out.println("Depositing $500...");
      c.deposit(500.00);
      try
      
         System.out.println("\nWithdrawing $100...");
         c.withdraw(100.00);
         System.out.println("\nWithdrawing $600...");
         c.withdraw(600.00);
      catch(InsufficientFundsException e)
      
         System.out.println("Sorry, but you are short $"
                                  + e.getAmount());
         e.printStackTrace();