update:demo5

com/study/demo5/Main.java

@@ -0,0 +1,17 @@
+package com.study.demo5;
+
+ public class Main {
+    public static void main(String[] args) {
+        // 7.1 测试
+        FileCopy fc = new FileCopy();
+        fc.copy("source.txt", "target.txt");
+        // 7.2 测试
+        DataIO dataIO = new DataIO();
+        dataIO.writeConfig("config.bin");
+        dataIO.readConfig("config.bin");
+        // 7.3 测试
+        FileStat fs = new FileStat();
+        long size = fs.countBytes("test3.txt");
+        System.out.println("文件大小: " + size + " 字节");
+    }
+}