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最后部分JavaSE加强.md

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+# 日志
+
+## 日志框架
+
+![image-20260104152029322](https://gitee.com/icecat2233/picture/raw/master/20260104152038794.png)
+
+![image-20260104152046997](https://gitee.com/icecat2233/picture/raw/master/20260104152050886.png)
+
+# 枚举
+
+**一般用作信息的标记和分类**
+
+![image-20260104152756174](https://gitee.com/icecat2233/picture/raw/master/20260104152757423.png)
+
+## 枚举的特点
+
+<img src="https://gitee.com/icecat2233/picture/raw/master/20260104153711421.png" alt="image-20260104153710216" style="zoom:50%;" />
+
+作用：
+
+代码优雅，可读性高，入参约束严谨
+
+# 类加载器
+
+**过程**
+
+<img src="https://gitee.com/icecat2233/picture/raw/master/20260105160250925.png" alt="image-20260105160242903" style="zoom: 50%;" />
+
+类加载器的分类
+
+![image-20260105161129784](https://gitee.com/icecat2233/picture/raw/master/20260105161131223.png)
+
+**双亲委派模型：**
+
+
+
+# 反射：
+
+## 如何创建类的字节码对象：
+
+
+
+## 反射类中的构造方法
+
+其中返回单个构造方法对象括号中给的参数是可变参数，给的是字节码文件参数，用来代表返回的是有参构造还是无参构造，可看下边例子
+
+![image-20260105170936519](https://gitee.com/icecat2233/picture/raw/master/20260105170937538.png)
+
+**反射到Constructor类中后的创建对象方法**
+
+![image-20260105171056746](https://gitee.com/icecat2233/picture/raw/master/20260105171057963.png)
+
+其中newInstance方法中的参数代表了是走的带参构造还是无参构造
+
+```Java
+public class Demo1 {
+    public static void main(String[] args) throws Exception{
+        //获取类的字节码对象
+        Class<?> class1 = Class.forName("com.ice.cat.domain.Student");
+        //反射构造方法对象
+        Constructor<?> constructor = class1.getDeclaredConstructor(String.class,int.class);//此方法无视权限返回单个所有权限的构造方法对象
+        //设置为true 表示取消访问检查
+        constructor.setAccessible(true);
+        //通过此方法实例化，创建对象
+        Object o = constructor.newInstance("杏菜",15);
+        System.out.println(o);
+    }
+}
+```
+
+## 反射类中的成员变量：
+
+![image-20260105173059327](https://gitee.com/icecat2233/picture/raw/master/20260105173100700.png)
+
+## 设置成员变量的方法
+
+![image-20260105173145296](https://gitee.com/icecat2233/picture/raw/master/20260105173146440.png)
+
+例子：
+
+```Java
+public class Demo2 {
+    public static void main(String[] args)throws Exception{
+        //获取Student的字节码文件
+        Class<Student> studentClass = Student.class;
+        //暴力获取单个所有权限无参构造方法
+        Constructor<Student> constructor = studentClass.getDeclaredConstructor();
+        //取消检查权限
+        constructor.setAccessible(true);
+        //实例化
+        Student stu1 = constructor.newInstance();
+        Student stu2 = constructor.newInstance();
+        //暴力反射内部成员变量
+        Field name = studentClass.getDeclaredField("name");
+        Field age = studentClass.getDeclaredField("age");
+        //因为是暴力获取，得设置访问权限
+        name.setAccessible(true);
+        age.setAccessible(true);
+        //通过set给成员变量赋值
+        name.set(stu1,"杏菜");
+        name.set(stu2,"佳树");
+        age.set(stu1,15);
+        age.set(stu2,13);
+        System.out.println(name.get(stu1));
+        System.out.println(name.get(stu2));
+    }
+}
+```
+
+## 反射的建议：禁止暴力反射
+
+小知识点：Java中的泛型是假的，只有在编译期间有效
+
+```Java
+public class Test1 {
+    //在一个泛型为Integer的集合里面添加一个字符串
+    //思路：Java中的泛型是假的，只有在编译期间有效
+    public static void main(String[] args) throws NoSuchMethodException, InvocationTargetException, IllegalAccessException {
+        ArrayList<Integer> list = new ArrayList<>();
+        Collections.addAll(list,1,2,3,4);
+        Class<? extends ArrayList> class1 = list.getClass();
+        Method add = class1.getMethod("add", Object.class);
+        add.invoke(list,"hhh");
+        System.out.println(list);
+    }
+}
+```
+
+# 方法引用：
+
+<img src="https://gitee.com/icecat2233/picture/raw/master/20260106153308790.png" alt="image-20260106153259853" style="zoom:50%;" />
+
+# Junit单元测试：
+
+<img src="https://gitee.com/icecat2233/picture/raw/master/20260106153753082.png" alt="image-20260106153751296" style="zoom:50%;" />
+
+## 总结：
+
+<img src="https://gitee.com/icecat2233/picture/raw/master/20260106154608910.png" alt="image-20260106154607624" style="zoom:50%;" />