feat(class36): 代码块的使用

- 新增 Test 类，包含静态代码块和普通代码块
-静态代码块用于初始化类级别的资源，如扑克牌数组- 普通代码块用于初始化对象的实例资源
-通过 main 方法演示代码块的执行顺序和作用

src/class31/Test.java

@@ -0,0 +1,30 @@
+package class31;
+
+public class Test {
+    public static void main(String[] args) {
+        People p = new Student();
+        Driver d = new Student();
+        BoyFriend b = new Student();
+
+        Driver a =new Student();
+        BoyFriend bf = new Student();
+//        br.drive(); 错误, BoyFriend接口没有drive方法
+        a.drive();
+
+
+
+
+    }
+}
+interface Driver{
+    void drive();
+}
+interface BoyFriend{}
+
+class People{}
+class Student extends People implements Driver,BoyFriend{
+    @Override
+    public void drive() {
+
+    }
+}

src/class36/Test.java

@@ -0,0 +1,29 @@
+package class36;
+
+import java.util.Arrays;
+
+public class Test {
+    public static String[] cards = new String[46];
+    static {
+        // 静态代码块 static修饰 属于类 与类一起加载运行 只运行一次
+        System.out.println("静态代码块");
+        cards[0] = "大王";
+        cards[1] = "小王";
+        for (int i = 2; i < 15; i++) {
+            cards[i] = i + "方片";
+            cards[i + 13] = i + "梅花";
+            cards[i + 26] = i + "草花";
+            cards[i + 31] = i + "黑桃";
+        }
+    }
+    //初始化对象的实例资源，随实例创建而运行
+    {
+        System.out.println("普通代码块");
+    }
+    public static void main(String[] args) {
+//        目标：认识代码块，搞清楚代码块的作用
+        System.out.println(Arrays.toString(cards));
+        new Test();
+    }
+
+}