public class TestException {
 public static void main(String[] args) {
  int c = 0;
  try
  {
   int a = 3;
   int b = 0;
   // 這塊代碼出現(xiàn)了異常
   c = a / b;
   // 那么異常之后的代碼都不會(huì)被執(zhí)行
   System.out.println("Hello World");
  }
  catch (ArithmeticException e)
  {
   System.out.println("除數(shù)不能為零");
  }
  finally
  {
   //不管有沒有發(fā)生異常，finally語句塊都會(huì)被執(zhí)行
   System.out.println("Welcome");
  }
  System.out.println(c);
  // 當(dāng)b為0時(shí)，有異常，輸出為c的初始值0
 }
 }
 //輸出結(jié)果：除數(shù)不能為零 Welcome 0

try異常

import java.io.FileInputStream;
import java.io.FileNotFoundException;
public class DemoException {
 public static void main(String[] args) {
 int a=test3();
 System.out.println(a); 
 }
 @SuppressWarnings("finally")
 public static int test3(){
 try {
  System.out.println(9 / 0);
  return 1;
 } catch (Exception e) {
  System.out.println("捕獲到了異常....");
  return 2;
 }finally{ 
  System.out.println("無論如何都會(huì)執(zhí)行的代碼...");
  return 3;
 }
 }
}
//輸出結(jié)果 "呵呵""哈哈" 3

帶有return異常

 //throws在方法體頭部通過聲明 拋出異常...
 public void dealFile() throws FileNotFoundException{
  FileInputStream fis =new FileInputStream("C:/name.txt");
 }
 //那么那么上面調(diào)用這個(gè)方法可以選擇是繼續(xù)拋出，還是捕獲異常

public class TestException {
 public static void main(String[] args) {
   try {
   Test3(); //這里選擇直接捕獲異常，而不是在拋出異常
   } catch (NumberFormatException e) {
   System.err.println("非數(shù)據(jù)類型不能轉(zhuǎn)換。");
  } //System.err.println();這種輸出方式可以輸出錯(cuò)誤的消息，在控制臺(tái)呈現(xiàn)紅色。
  }
  public static void Test3() throws NumberFormatException{ 
   String s = "abc"; 
  System.out.println(Double.parseDouble(s)); 
  } 
 }

throws異常

public class TestException {
 public static void main(String[] args) {
  String s = "abc"; 
  if(s.equals("abc")) { 
   throw new NumberFormatException("不能相等");
   } else { 
   System.out.println(s); 
  } 
  } 
 }

throw異常

 public class MyException extends Exception
{
 public MyException()
 {
 super();
 } 
 public MyException(String message)
 {
 super(message);
 }
}

public class ExceptionTest4
{
 public void method(String str) throws MyException
 {
 if(null == str)
 {
  throw new MyException("傳入的字符串參數(shù)不能為null！");
 }
 else
 {
  System.out.println(str);
 }
 }
 public static void main(String[] args) throws MyException //異常處理方式1，不斷向外拋出
 {
 ExceptionTest4 test = new ExceptionTest4();
 test.method(null);
 }
}

public class ExceptionTest4
{
 public void method(String str) throws MyException
 {
 if (null == str)
 {
  throw new MyException("傳入的字符串參數(shù)不能為null！");
 }
 else
 {
  System.out.println(str);
 }
 }
 public static void main(String[] args)
 {
 //異常處理方式2，采用try...catch語句
 try
 {
  ExceptionTest4 test = new ExceptionTest4();
  test.method(null);
 }
 catch (MyException e)
 {
  e.printStackTrace();
 } 
 finally
 {
  System.out.println("程序處理完畢");
 }
 }
}