java异常的捕获和处理
system.exit(输入一个非零的数);
表示程序退出。
system.err.println
表示输出的是红色的字体
java中所有的异常都是Exception(父类)
除数为0的异常,ArithmeticException(子类)
输入格式不正确,InputMismathException(子类)
作业:
1、
package com.yichang; import java.util.Scanner; public class LianXi { public static void main(String[] args) { Scanner sc = new Scanner(System.in); System.out.println("请输入课程代号(1~3之间的数):"); try { int daihao = 0; daihao = sc.nextInt(); if(daihao == 1) { System.out.println("c#编程"); }else if(daihao == 2) { System.out.println("java编程"); }else if(daihao == 3) { System.out.println("php编程"); }else { System.err.println("输入错误!"); } } catch (Exception e) { System.err.println("输入错误!"); }finally { System.out.println("欢迎提出建议!"); } } }
2、
package com.yichang; public class Person { private String name; private String sex; private int age; public String getName() { return name; } public void setName(String name) { this.name = name; } public String getSex() { return sex; } public void setSex(String sex) { this.sex = sex; } public int getAge() { return age; } public void setAge(int age) throws Exception{ if(age>1 && age<100) { this.age = age; }else { throw new Exception("年龄必须在1到100之间"); } } public void print() { System.out.println(this.getName()+"-"+this.getSex()+"-"+this.getAge()); } }
package com.yichang; public class Test2 { public static void main(String[] args) { Person p = new Person(); try { p.setAge(150); p.print(); } catch (Exception e) { e.printStackTrace(); } } }