java基础异常处理
异常的定义:中断了正常指令流的事件。
try..catch..finally结构:
class Test{ public static void main(String[] args){ System.out.println(1); try{ System.out.println(2); int i = 1 / 0; System.out.println(3); } catch(Exception e){ e.printStackTrace(); System.out.println(4); } finally{ System.out.println(5); } System.out.println(6); } }
输出结果:
D:\Java\code\练习十二>java Test 1 2 java.lang.ArithmeticException: / by zero at Test.main(Test.java:6) 4 5 6
throw与throws关键字
class User{ private int age; public void setAge(int age) throws Exception{ if(age <= 0){ Exception e = new Exception("input age is error!"); throw e; } else{ this.age=age; } } }
class Test{ public static void main(String[] args){ User u = new User(); try{ u.setAge(-20); } catch(Exception e){ System.out.println(e); } } }
D:\Java\code\练习十二>java Test java.lang.Exception: input age is error!