枚举类实现单例，添加枚举类内部方法，反编译文件展示

jad/EnumInstance.java

@@ -5,6 +5,8 @@
 
 package top.fjy8018.designpattern.pattern.creational.singleton;
 
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 public final class EnumInstance extends Enum
 {
@@ -34,12 +36,13 @@ public final class EnumInstance extends Enum
         this.data = data;
     }
 
-    public Object getInstance()
+    public static EnumInstance getInstance()
     {
         return INSTANCE;
     }
 
     public static final EnumInstance INSTANCE;
+    private static final Logger log = LoggerFactory.getLogger(top/fjy8018/designpattern/pattern/creational/singleton/EnumInstance);
     private Object data;
     private static final EnumInstance $VALUES[];
 

jad/EnumInstance_addMethod.java

@@ -0,0 +1,68 @@
+// Decompiled by Jad v1.5.8g. Copyright 2001 Pavel Kouznetsov.
+// Jad home page: http://www.kpdus.com/jad.html
+// Decompiler options: packimports(3) 
+// Source File Name:   EnumInstance.java
+
+package top.fjy8018.designpattern.pattern.creational.singleton;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public abstract class EnumInstance extends Enum
+{
+
+    public static EnumInstance[] values()
+    {
+        return (EnumInstance[])$VALUES.clone();
+    }
+
+    public static EnumInstance valueOf(String name)
+    {
+        return (EnumInstance)Enum.valueOf(top/fjy8018/designpattern/pattern/creational/singleton/EnumInstance, name);
+    }
+
+    private EnumInstance(String s, int i)
+    {
+        super(s, i);
+    }
+
+    protected abstract void logTest();
+
+    public Object getData()
+    {
+        return data;
+    }
+
+    public void setData(Object data)
+    {
+        this.data = data;
+    }
+
+    public static EnumInstance getInstance()
+    {
+        return INSTANCE;
+    }
+
+
+    public static final EnumInstance INSTANCE;
+    private static final Logger log = LoggerFactory.getLogger(top/fjy8018/designpattern/pattern/creational/singleton/EnumInstance);
+    private Object data;
+    private static final EnumInstance $VALUES[];
+
+    static 
+    {
+        INSTANCE = new EnumInstance("INSTANCE", 0) {
+
+            protected void logTest()
+            {
+                EnumInstance.log.info((new StringBuilder()).append(top/fjy8018/designpattern/pattern/creational/singleton/EnumInstance.getSimpleName()).append("\u6253\u5370\u8F93\u51FA").toString());
+            }
+
+        }
+;
+        $VALUES = (new EnumInstance[] {
+            INSTANCE
+        });
+    }
+
+}

src/main/java/top/fjy8018/designpattern/pattern/creational/singleton/EnumInstance.java

@@ -1,5 +1,7 @@
 package top.fjy8018.designpattern.pattern.creational.singleton;
 
+import lombok.extern.slf4j.Slf4j;
+
 /**
  * 枚举单例模式（effective Java推荐）
  * 枚举类天生可序列化，有效防止序列化攻击
@@ -13,11 +15,21 @@ package top.fjy8018.designpattern.pattern.creational.singleton;
  * @author F嘉阳
  * @date 2018-09-24 20:30
  */
+@Slf4j
 public enum EnumInstance {
     /**
      * 单例枚举
      */
-    INSTANCE;
+    INSTANCE {
+        @Override
+        protected void logTest() {
+            log.info(EnumInstance.class.getSimpleName() + "打印输出");
+        }
+    };
+
+    public static EnumInstance getInstance() {
+        return INSTANCE;
+    }
 
     /**
      * 目标实例化对象
@@ -32,7 +44,6 @@ public enum EnumInstance {
         this.data = data;
     }
 
-    public Object getInstance() {
-        return INSTANCE;
-    }
+    // 提供外部访问方法入口
+    protected abstract void logTest();
 }

src/test/java/top/fjy8018/designpattern/pattern/creational/singleton/EnumInstanceTest.java

@@ -0,0 +1,14 @@
+package top.fjy8018.designpattern.pattern.creational.singleton;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class EnumInstanceTest {
+
+    @Test
+    void logTest() {
+        EnumInstance instance = EnumInstance.getInstance();
+        instance.logTest();
+    }
+}

src/test/java/top/fjy8018/designpattern/pattern/creational/singleton/SingletonReflectAttack.java

@@ -7,8 +7,6 @@ import java.lang.reflect.Constructor;
 import java.lang.reflect.Field;
 import java.lang.reflect.InvocationTargetException;
 
-import static org.junit.jupiter.api.Assertions.*;
-
 /**
  * 单例模式反射攻击
  */
@@ -37,7 +35,7 @@ class SingletonReflectAttack {
         // 通过反射获取实例
         EnumInstance reflectInstance = (EnumInstance) constructor.newInstance("fjy", 123);
         // 通过正常方式获取
-        EnumInstance instance = EnumInstance.INSTANCE;
+        EnumInstance instance = EnumInstance.getInstance();
 
         // 判断是否同一个对象
         log.info("反射方式：" + reflectInstance.getData());

src/test/java/top/fjy8018/designpattern/pattern/creational/singleton/SingletonSerializableAttackTest.java

@@ -41,7 +41,7 @@ class SingletonSerializableAttackTest {
     @Test
     void EnumInstanceGetInstance() throws Exception {
 
-        EnumInstance singleton = EnumInstance.INSTANCE;
+        EnumInstance singleton = EnumInstance.getInstance();
         singleton.setData(new Object());
 
         ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream(FILE_NAME));