优化内容

Author: Shusheng Shi

.gitignore

@@ -0,0 +1,26 @@
+# Compiled class file
+*.class
+
+# Log file
+*.log
+
+# BlueJ files
+*.ctxt
+
+# Mobile Tools for Java (J2ME)
+.mtj.tmp/
+
+# Package Files #
+*.jar
+*.war
+*.ear
+*.zip
+*.tar.gz
+*.rar
+
+# virtual machine crash logs, see http://www.java.com/en/download/help/error_hotspot.xml
+hs_err_pid*
+
+/.idea/
+/target/
+/*.iml

LICENSE

@@ -0,0 +1,201 @@
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.

README.md

@@ -0,0 +1,78 @@
+## 1 目标
+致力于构建全球最完善的 Java 高并发理论体系。让我们的程序更加可靠，跳槽面试更轻松。
+
+## 高并发方案概要
+
+### 线程安全性
+线程安全性，主要从原子性、可见性、有序性
+
+### 安全发布对象
+安全发布对象的一些核心方法，主要通过单例类的多种实现方式体会，这也是对线程安全性的巩固，也是把线程安全性涉及的一些关键字和类再一次放到实际场景使用。
+
+### 线程安全策略
+线程安全策略，包括定义不可变对象、线程封闭、同步容器、并发容器等，引出并发里的关键知识J.U.C。
+同时还额外介绍了开发中常见的一些线程不安全类和写法，并给出他们各自对应的替代方案。
+
+### AQS
+J.U.C的重要组件，面试必问考点。
+
+AQS模型设计及相关同步组件的原理和使用，都非常实用，包括：CountDownLatch、Semaphore、CyclicBarrier、ReentrantLock与锁、Condition等。
+
+这些组件需要大家能熟练明白他们的用途及差异，不但会使用，而且还要明确知道不同方法调用后的不同效果。
+
+### J.U.C组件拓展
+
+J.U.C相关组件，主要包括FutureTask、Fork/Join框架、BlockingQueue，其中FutureTask讲解时会对比着Callable、Runnable、Future来讲。
+
+这些组件使用场景相对AQS会少一些，但也是J.U.C的重要组成部分，也是需要掌握的
+
+### 线程调度-线程池
+new Thread弊端、线程池的好处、ThreadPoolExecutor详细介绍（参数、状态、方法）、线程池类图、Executor框架接口
+
+### 多线程并发拓展
+死锁产生的条件及预防、多线程并发编程的最佳实践、Spring与线程安全、以及面试都特别喜欢问的HashMap和ConcurrentMap源码细节
+
+### 扩容
+垂直扩容和水平扩容的区别，数据库读操作扩展和写操作扩展
+
+### 缓存
+缓存特征（命中率、最大元素、清空策略）、影响缓存命中率因素、缓存分类和应用场景（本地缓存、分布式缓存）、高并发场景下缓存常见问题（缓存一致性、缓存并发、缓存穿透、雪崩）
+
+### MQ
+消息队列的特性（业务无关、FIFO、容灾、性能）、为什么需要消息队列以及消息队列的好处（业务解耦、最终一致性、广播、错峰与流控）
+
+### 应用拆分
+
+### 限流
+明确限流的重要作用
+限流常用的四种算法：计数法、滑动窗口、漏桶算法和令牌桶算法
+
+### 服务降级与服务熔断
+服务降级的分类：自动降级（超时、失败次数、故障、限流）和人工降级（开关），总结了服务降级和服务熔断的共性（目的、最终表现、粒度、自治）和区别（出发原因、管理目标层次、实现方式）以及服务降级要考虑的问题
+
+### 分库分表
+
+## QQ 技术交流群
+
+为大家提供一个学习交流平台，在这里你可以自由地讨论技术问题。
+
+<img src="assets/QQ 群.JPG" width="180px">
+
+## 微信交流群
+<img src="assets/微信群.jpeg" width="180px">
+
+### 本人微信
+<img src="assets/个人微信.jpeg" width="180px">
+
+## Java源码模拟面试解析指南
+
+<a href="https://www.nowcoder.com/tutorial/10029/index">
+    <img src="assets/牛客专刊.png" width="80px"></a>
+
+
+### 绘图工具
+
+- [draw.io](https://www.draw.io/)
+- keynote
+## 知识体系
+![](https://uploadfiles.nowcoder.com/files/20190815/5088755_1565799768221_4685968-76a236d781f7dee7.png)

assets/LOGO.png

@@ -0,0 +1,9 @@
+package AppendixA;
+
+public class Main {
+    public static void main(String[] args) {
+        System.out.println(Thread.currentThread().getName() + ":BEGIN");
+        new MyFrame();
+        System.out.println(Thread.currentThread().getName() + ":END");
+    }
+}

assets/QQ 群.JPG

@@ -0,0 +1,63 @@
+package AppendixA;
+
+import javax.swing.JFrame;
+import javax.swing.JButton;
+import javax.swing.JLabel;
+import javax.swing.SwingUtilities;
+import java.awt.FlowLayout;
+import java.awt.event.ActionEvent;
+import java.awt.event.ActionListener;
+
+
+public class MyFrame extends JFrame implements ActionListener {
+    private final JLabel label = new JLabel("Event Dispatching Thread Sample");
+    private final JButton button = new JButton("countUp");
+    public MyFrame() {
+        super("MyFrame");
+        getContentPane().setLayout(new FlowLayout());
+        getContentPane().add(label);
+        getContentPane().add(button);
+        button.addActionListener(this);
+        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
+        pack();
+        setVisible(true);
+    }
+    public void actionPerformed(ActionEvent e) {
+        if (e.getSource() == button) {
+            countUp();
+        }
+    }
+    private void countUp() {
+        System.out.println(Thread.currentThread().getName() + ":countUp:BEGIN");
+
+        // invokerThread��ָ��ʱ����sleep֮�󣬵���SwingUtilities.invokeLater
+        new Thread("invokerThread") {
+            public void run() {
+                System.out.println(Thread.currentThread().getName() + ":invokerThread:BEGIN");
+                for (int i = 0; i < 10; i++) {
+                    final String string = "" + i;
+                    try {
+                        // executor�ᱻ��Event Dispatching Thread����
+                        final Runnable executor = new Runnable() {
+                            public void run() {
+                                System.out.println(Thread.currentThread().getName() + ":executor:BEGIN:string = " + string);
+                                label.setText(string);
+                                System.out.println(Thread.currentThread().getName() + ":executor:END");
+                            }
+                        };
+
+                        // ��Event Dispatching Thread���ó�exector
+                        SwingUtilities.invokeLater(executor);
+
+                        Thread.sleep(1000);
+                    } catch (Exception e) {
+                        e.printStackTrace();
+                    }
+                }
+                System.out.println(Thread.currentThread().getName() + ":invokerThread:END");
+            }
+        }.start();
+
+        System.out.println(Thread.currentThread().getName() + ":countUp:END");
+    }
+}

assets/个人微信.jpeg

@@ -0,0 +1,15 @@
+package Balking.Q5;
+
+public class TestThread extends Thread {
+    public void run() {
+        System.out.print("BEGIN");
+        for (int i = 0; i < 50; i++) {
+            System.out.print(".");
+            try {
+                Thread.sleep(100);
+            } catch (InterruptedException e) {
+            }
+        }
+        System.out.println("END");
+    }
+}