update:demo2

com/study/demo2/Account_Main.java

@@ -0,0 +1,15 @@
+package com.study.demo2;
+
+public class Main {
+    public static void main(String[] args) {
+        Account acc1 = new Account("A001", "张三", 1000);
+        Account acc2 = new Account("A002", "李四", 500);
+        
+        acc1.deposit(200);
+        acc1.withdraw(100);
+        acc1.transfer(acc2, 300);
+        
+        System.out.println("账户1余额:" + acc1.getBalance());
+        System.out.println("账户2余额:" + acc2.getBalance());
+    }
+}