From 2e366f7d61ac6250374c32359d8ec7be22705b27 Mon Sep 17 00:00:00 2001
From: xuxin <840198532@qq.com>
Date: Wed, 5 Aug 2026 13:59:25 +0800
Subject: [PATCH] =?UTF-8?q?s-day05-=E8=87=AA=E5=AE=9A=E4=B9=89=E5=BC=82?=
 =?UTF-8?q?=E5=B8=B8=E6=A1=88=E4=BE=8B?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 .../com/inmind/custom_exception06/Demo12.java | 41 +++++++++++++++++++
 .../custom_exception06/RegisterException.java | 18 ++++++++
 2 files changed, 59 insertions(+)
 create mode 100644 s-day05/src/com/inmind/custom_exception06/Demo12.java
 create mode 100644 s-day05/src/com/inmind/custom_exception06/RegisterException.java

diff --git a/s-day05/src/com/inmind/custom_exception06/Demo12.java b/s-day05/src/com/inmind/custom_exception06/Demo12.java
new file mode 100644
index 0000000..31bb260
--- /dev/null
+++ b/s-day05/src/com/inmind/custom_exception06/Demo12.java
@@ -0,0 +1,41 @@
+package com.inmind.custom_exception06;
+
+import java.util.Scanner;
+
+/*
+在上述代码中，发现这些异常都是JDK内部定义好的，但是实际开发中也会出现很多异常,这些异常很可能在JDK中没有定义过,
+例如年龄负数问题,考试成绩负数问题.那么能不能自己定义异常呢？
+
+要求：我们模拟注册操作，如果用户名已存在，则抛出异常并提示：亲，该用户名已经被注册。
+使用异常来实现,用户名已注册的信息提示业务逻辑
+ */
+public class Demo12 {
+    //静态变量表示已经注册过的用户名
+    static String[] usernames = {"jack", "tom", "rose"};
+
+    public static void main(String[] args) {
+        try {
+            //接收用户输入的用户名
+            Scanner sc = new Scanner(System.in);
+            System.out.println("请输入用户名：");
+            String username = sc.nextLine();
+            //判断下该用户名是否可用
+            checkUsername(username);
+            System.out.println("恭喜你，注册成功！");
+        } catch (RegisterException e) {
+            System.out.println(e.getMessage());
+            e.printStackTrace();
+        }
+        System.out.println("程序结束");
+    }
+    //使用自定义的异常，来处理用户名已注册的业务场景
+    private static void checkUsername(String username) {
+        for (String u : usernames) {
+            if (u.equals(username)) {
+               //主动抛出异常
+                throw new RegisterException("亲，该用户名已经被注册");
+            }
+        }
+    }
+
+}
diff --git a/s-day05/src/com/inmind/custom_exception06/RegisterException.java b/s-day05/src/com/inmind/custom_exception06/RegisterException.java
new file mode 100644
index 0000000..41a3045
--- /dev/null
+++ b/s-day05/src/com/inmind/custom_exception06/RegisterException.java
@@ -0,0 +1,18 @@
+package com.inmind.custom_exception06;
+/*
+自定义异常:
+        1.编译时异常:提醒代码有语法问题或者声明了某些异常(继承Exception)
+        2.运行时异常:用来处理业务逻辑(继承RuntimeException)
+ */
+public class RegisterException extends RuntimeException{
+    //默认无参构造方法
+    public RegisterException(){
+        super();//不写，编译器也会自动加
+    }
+
+    //有参构造方法
+    public RegisterException(String msg){
+        super(msg);//调用父类的构造方法，将msg保存下来
+    }
+
+}