[update] java12-example 示例完成

java13-example 示例完成

demo2/java12-example/src/main/java/Java12Main.java

@@ -0,0 +1,50 @@
+import java.io.IOException;
+import java.lang.constant.ClassDesc;
+import java.nio.file.Files;
+import java.nio.file.Path;
+
+/**
+ * @author maxiaofeng
+ * @date 2025/7/18 10:06
+ */
+public class Java12Main {
+    public static void main(String[] args) {
+        System.out.println("Java 12 Features Demo");
+        switchExample();
+        try {
+            fileComparisonExample();
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+        constantAPIExample();
+    }
+
+    // Switch表达式示例
+    public static void switchExample() {
+        int day = 3;
+        String dayType = switch (day) {
+            case 1, 2, 3, 4, 5 -> "Weekday";
+            case 6, 7 -> "Weekend";
+            default -> throw new IllegalArgumentException("Invalid day: " + day);
+        };
+        System.out.println("Switch表达式结果: " + dayType);
+    }
+
+    // 文件对比示例
+    public static void fileComparisonExample() throws IOException {
+        Path file1 = Files.createTempFile("file1", ".txt");
+        Path file2 = Files.createTempFile("file2", ".txt");
+        Files.writeString(file1, "Hello");
+        Files.writeString(file2, "World");
+        // 输出第一个差异字节位置（0-based）
+        System.out.println("文件差异位置: " + Files.mismatch(file1, file2));
+        Files.delete(file1);
+        Files.delete(file2);
+    }
+
+    // 常量API示例
+    public static void constantAPIExample() {
+        ClassDesc c = ClassDesc.of("java.lang.String");
+        System.out.println("类描述: " + c.displayName());
+    }
+}

demo2/java12-example/src/main/java/Main.java

@@ -1,9 +0,0 @@
-/**
- * @author maxiaofeng
- * @date 2025/7/18 10:06
- */
-public class Main {
-    public static void main(String[] args) {
-        System.out.println("hello java8.");
-    }
-}