From 7d8fbfcd30d5b3142ddf7505696980bb1cf3ddee Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E5=88=98=E6=B4=AA=E5=AE=9D?= <liuhongbao@zhiguanapp.com>
Date: Thu, 27 Sep 2018 18:09:18 +0800
Subject: [PATCH] update

---
 .idea/golang-design-patterns.iml |   8 +
 .idea/misc.xml                   |   6 +
 .idea/modules.xml                |   8 +
 .idea/vcs.xml                    |   6 +
 .idea/workspace.xml              | 279 +++++++++++++++++++++++++++++++
 README.md                        |  55 +++++-
 singleton/README.md              | 196 ++++++++++++++++++++++
 singleton/double-check-lock.go   |  34 ++++
 singleton/lazy-loading.go        |  35 ++++
 singleton/starving-loading.go    |  31 ++++
 10 files changed, 657 insertions(+), 1 deletion(-)
 create mode 100644 .idea/golang-design-patterns.iml
 create mode 100644 .idea/misc.xml
 create mode 100644 .idea/modules.xml
 create mode 100644 .idea/vcs.xml
 create mode 100644 .idea/workspace.xml
 create mode 100644 singleton/README.md
 create mode 100644 singleton/double-check-lock.go
 create mode 100644 singleton/lazy-loading.go
 create mode 100644 singleton/starving-loading.go

diff --git a/.idea/golang-design-patterns.iml b/.idea/golang-design-patterns.iml
new file mode 100644
index 0000000..c956989
--- /dev/null
+++ b/.idea/golang-design-patterns.iml
@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<module type="WEB_MODULE" version="4">
+  <component name="NewModuleRootManager">
+    <content url="file://$MODULE_DIR$" />
+    <orderEntry type="inheritedJdk" />
+    <orderEntry type="sourceFolder" forTests="false" />
+  </component>
+</module>
\ No newline at end of file
diff --git a/.idea/misc.xml b/.idea/misc.xml
new file mode 100644
index 0000000..28a804d
--- /dev/null
+++ b/.idea/misc.xml
@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="JavaScriptSettings">
+    <option name="languageLevel" value="ES6" />
+  </component>
+</project>
\ No newline at end of file
diff --git a/.idea/modules.xml b/.idea/modules.xml
new file mode 100644
index 0000000..0a86d19
--- /dev/null
+++ b/.idea/modules.xml
@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="ProjectModuleManager">
+    <modules>
+      <module fileurl="file://$PROJECT_DIR$/.idea/golang-design-patterns.iml" filepath="$PROJECT_DIR$/.idea/golang-design-patterns.iml" />
+    </modules>
+  </component>
+</project>
\ No newline at end of file
diff --git a/.idea/vcs.xml b/.idea/vcs.xml
new file mode 100644
index 0000000..94a25f7
--- /dev/null
+++ b/.idea/vcs.xml
@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="VcsDirectoryMappings">
+    <mapping directory="$PROJECT_DIR$" vcs="Git" />
+  </component>
+</project>
\ No newline at end of file
diff --git a/.idea/workspace.xml b/.idea/workspace.xml
new file mode 100644
index 0000000..dafc2b4
--- /dev/null
+++ b/.idea/workspace.xml
@@ -0,0 +1,279 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="ChangeListManager">
+    <list default="true" id="1a1353c4-bdd9-41be-9088-eda7b22a7be5" name="Default" comment="" />
+    <option name="EXCLUDED_CONVERTED_TO_IGNORED" value="true" />
+    <option name="TRACKING_ENABLED" value="true" />
+    <option name="SHOW_DIALOG" value="false" />
+    <option name="HIGHLIGHT_CONFLICTS" value="true" />
+    <option name="HIGHLIGHT_NON_ACTIVE_CHANGELIST" value="false" />
+    <option name="LAST_RESOLUTION" value="IGNORE" />
+  </component>
+  <component name="FileEditorManager">
+    <leaf>
+      <file leaf-file-name="README.md" pinned="false" current-in-tab="false">
+        <entry file="file://$PROJECT_DIR$/README.md">
+          <provider selected="true" editor-type-id="split-provider[text-editor;markdown-preview-editor]">
+            <state split_layout="SPLIT">
+              <first_editor relative-caret-position="135">
+                <caret line="9" lean-forward="true" selection-start-line="9" selection-end-line="9" />
+              </first_editor>
+              <second_editor />
+            </state>
+          </provider>
+        </entry>
+      </file>
+      <file leaf-file-name="README.md" pinned="false" current-in-tab="true">
+        <entry file="file://$PROJECT_DIR$/singleton/README.md">
+          <provider selected="true" editor-type-id="split-provider[text-editor;markdown-preview-editor]">
+            <state split_layout="SPLIT">
+              <first_editor relative-caret-position="426">
+                <caret line="194" column="59" selection-start-line="194" selection-start-column="59" selection-end-line="194" selection-end-column="59" />
+              </first_editor>
+              <second_editor />
+            </state>
+          </provider>
+        </entry>
+      </file>
+      <file leaf-file-name="lazy-loading.go" pinned="false" current-in-tab="false">
+        <entry file="file://$PROJECT_DIR$/singleton/lazy-loading.go">
+          <provider selected="true" editor-type-id="text-editor">
+            <state relative-caret-position="348">
+              <caret line="27" selection-start-line="27" selection-end-line="34" selection-end-column="1" />
+            </state>
+          </provider>
+        </entry>
+      </file>
+      <file leaf-file-name="starving-loading.go" pinned="false" current-in-tab="false">
+        <entry file="file://$PROJECT_DIR$/singleton/starving-loading.go">
+          <provider selected="true" editor-type-id="text-editor">
+            <state relative-caret-position="68">
+              <caret line="9" selection-start-line="9" selection-end-line="31" />
+            </state>
+          </provider>
+        </entry>
+      </file>
+      <file leaf-file-name="double-check-lock.go" pinned="false" current-in-tab="false">
+        <entry file="file://$PROJECT_DIR$/singleton/double-check-lock.go">
+          <provider selected="true" editor-type-id="text-editor">
+            <state relative-caret-position="120">
+              <caret line="11" selection-start-line="11" selection-end-line="33" selection-end-column="1" />
+              <folding>
+                <element signature="e#14#39#0" expanded="true" />
+              </folding>
+            </state>
+          </provider>
+        </entry>
+      </file>
+    </leaf>
+  </component>
+  <component name="FileTemplateManagerImpl">
+    <option name="RECENT_TEMPLATES">
+      <list>
+        <option value="Go File" />
+      </list>
+    </option>
+  </component>
+  <component name="GOROOT" path="/usr/local/Cellar/go/1.10.3/libexec" />
+  <component name="Git.Settings">
+    <option name="RECENT_GIT_ROOT_PATH" value="$PROJECT_DIR$" />
+  </component>
+  <component name="IdeDocumentHistory">
+    <option name="CHANGED_PATHS">
+      <list>
+        <option value="$PROJECT_DIR$/README.md" />
+        <option value="$PROJECT_DIR$/singleton/main.go" />
+        <option value="$PROJECT_DIR$/singleton/starving-loading.go" />
+        <option value="$PROJECT_DIR$/singleton/lazy-loading.go" />
+        <option value="$PROJECT_DIR$/singleton/double-check-lock.go" />
+        <option value="$PROJECT_DIR$/singleton/README.md" />
+      </list>
+    </option>
+  </component>
+  <component name="JsBuildToolGruntFileManager" detection-done="true" sorting="DEFINITION_ORDER" />
+  <component name="JsBuildToolPackageJson" detection-done="true" sorting="DEFINITION_ORDER" />
+  <component name="JsGulpfileManager">
+    <detection-done>true</detection-done>
+    <sorting>DEFINITION_ORDER</sorting>
+  </component>
+  <component name="NodePackageJsonFileManager">
+    <packageJsonPaths />
+  </component>
+  <component name="ProjectFrameBounds" fullScreen="true">
+    <option name="width" value="1440" />
+    <option name="height" value="900" />
+  </component>
+  <component name="ProjectView">
+    <navigator proportions="" version="1">
+      <foldersAlwaysOnTop value="true" />
+    </navigator>
+    <panes>
+      <pane id="Scope" />
+      <pane id="ProjectPane">
+        <subPane>
+          <expand>
+            <path>
+              <item name="golang-design-patterns" type="b2602c69:ProjectViewProjectNode" />
+              <item name="golang-design-patterns" type="462c0819:PsiDirectoryNode" />
+            </path>
+            <path>
+              <item name="golang-design-patterns" type="b2602c69:ProjectViewProjectNode" />
+              <item name="golang-design-patterns" type="462c0819:PsiDirectoryNode" />
+              <item name="singleton" type="462c0819:PsiDirectoryNode" />
+            </path>
+          </expand>
+          <select />
+        </subPane>
+      </pane>
+    </panes>
+  </component>
+  <component name="PropertiesComponent">
+    <property name="DefaultGoTemplateProperty" value="Go File" />
+    <property name="go.gopath.indexing.explicitly.defined" value="true" />
+    <property name="go.sdk.automatically.set" value="true" />
+    <property name="last_opened_file_path" value="$PROJECT_DIR$" />
+    <property name="nodejs_interpreter_path.stuck_in_default_project" value="undefined stuck path" />
+    <property name="nodejs_npm_path_reset_for_default_project" value="true" />
+  </component>
+  <component name="RunDashboard">
+    <option name="ruleStates">
+      <list>
+        <RuleState>
+          <option name="name" value="ConfigurationTypeDashboardGroupingRule" />
+        </RuleState>
+        <RuleState>
+          <option name="name" value="StatusDashboardGroupingRule" />
+        </RuleState>
+      </list>
+    </option>
+  </component>
+  <component name="RunManager" selected="Go Build.go build double-check-lock.go">
+    <configuration name="go build double-check-lock.go" type="GoApplicationRunConfiguration" factoryName="Go Application" temporary="true" nameIsGenerated="true">
+      <module name="golang-design-patterns" />
+      <working_directory value="$PROJECT_DIR$/" />
+      <go_parameters value="-i" />
+      <kind value="FILE" />
+      <filePath value="$PROJECT_DIR$/singleton/double-check-lock.go" />
+      <package value="github.com/silsuer/golang-design-patterns" />
+      <directory value="$PROJECT_DIR$/" />
+    </configuration>
+    <configuration name="go build lazy-loading.go" type="GoApplicationRunConfiguration" factoryName="Go Application" temporary="true" nameIsGenerated="true">
+      <module name="golang-design-patterns" />
+      <working_directory value="$PROJECT_DIR$/" />
+      <go_parameters value="-i" />
+      <kind value="FILE" />
+      <filePath value="$PROJECT_DIR$/singleton/lazy-loading.go" />
+      <package value="github.com/silsuer/golang-design-patterns" />
+      <directory value="$PROJECT_DIR$/" />
+    </configuration>
+    <configuration name="go build main.go" type="GoApplicationRunConfiguration" factoryName="Go Application" temporary="true" nameIsGenerated="true">
+      <module name="golang-design-patterns" />
+      <working_directory value="$PROJECT_DIR$/" />
+      <go_parameters value="-i" />
+      <kind value="FILE" />
+      <filePath value="$PROJECT_DIR$/singleton/main.go" />
+      <package value="github.com/silsuer/golang-design-patterns" />
+      <directory value="$PROJECT_DIR$/" />
+    </configuration>
+    <configuration name="go build starving-loading.go" type="GoApplicationRunConfiguration" factoryName="Go Application" temporary="true" nameIsGenerated="true">
+      <module name="golang-design-patterns" />
+      <working_directory value="$PROJECT_DIR$/" />
+      <go_parameters value="-i" />
+      <kind value="FILE" />
+      <filePath value="$PROJECT_DIR$/singleton/starving-loading.go" />
+      <package value="github.com/silsuer/golang-design-patterns" />
+      <directory value="$PROJECT_DIR$/" />
+    </configuration>
+    <list>
+      <item itemvalue="Go Build.go build main.go" />
+      <item itemvalue="Go Build.go build lazy-loading.go" />
+      <item itemvalue="Go Build.go build starving-loading.go" />
+      <item itemvalue="Go Build.go build double-check-lock.go" />
+    </list>
+    <recent_temporary>
+      <list>
+        <item itemvalue="Go Build.go build double-check-lock.go" />
+        <item itemvalue="Go Build.go build starving-loading.go" />
+        <item itemvalue="Go Build.go build lazy-loading.go" />
+        <item itemvalue="Go Build.go build main.go" />
+      </list>
+    </recent_temporary>
+  </component>
+  <component name="ToolWindowManager">
+    <frame x="0" y="0" width="1440" height="900" extended-state="0" />
+    <editor active="true" />
+    <layout>
+      <window_info active="true" content_ui="combo" id="Project" order="0" visible="true" weight="0.25" />
+      <window_info anchor="bottom" id="TODO" order="6" />
+      <window_info anchor="bottom" id="Docker" show_stripe_button="false" />
+      <window_info anchor="bottom" id="Event Log" side_tool="true" />
+      <window_info anchor="right" id="Database" />
+      <window_info anchor="bottom" id="Database Changes" show_stripe_button="false" />
+      <window_info anchor="bottom" id="Run" order="2" visible="true" weight="0.32969698" />
+      <window_info anchor="bottom" id="Version Control" />
+      <window_info id="Structure" order="1" side_tool="true" weight="0.25" />
+      <window_info anchor="bottom" id="Terminal" weight="0.32969698" />
+      <window_info anchor="bottom" id="Debug" order="3" weight="0.4" />
+      <window_info id="Favorites" side_tool="true" />
+      <window_info anchor="bottom" id="Find" order="1" />
+      <window_info anchor="right" id="Commander" internal_type="SLIDING" order="0" type="SLIDING" weight="0.4" />
+      <window_info anchor="right" content_ui="combo" id="Hierarchy" order="2" weight="0.25" />
+      <window_info anchor="bottom" id="Inspection" order="5" weight="0.4" />
+      <window_info anchor="right" id="Ant Build" order="1" weight="0.25" />
+      <window_info anchor="bottom" id="Message" order="0" />
+      <window_info anchor="bottom" id="Cvs" order="4" weight="0.25" />
+    </layout>
+  </component>
+  <component name="TypeScriptGeneratedFilesManager">
+    <option name="version" value="1" />
+  </component>
+  <component name="VcsContentAnnotationSettings">
+    <option name="myLimit" value="2678400000" />
+  </component>
+  <component name="editorHistoryManager">
+    <entry file="file://$PROJECT_DIR$/README.md">
+      <provider selected="true" editor-type-id="split-provider[text-editor;markdown-preview-editor]">
+        <state split_layout="SPLIT">
+          <first_editor relative-caret-position="135">
+            <caret line="9" lean-forward="true" selection-start-line="9" selection-end-line="9" />
+          </first_editor>
+          <second_editor />
+        </state>
+      </provider>
+    </entry>
+    <entry file="file://$PROJECT_DIR$/singleton/lazy-loading.go">
+      <provider selected="true" editor-type-id="text-editor">
+        <state relative-caret-position="348">
+          <caret line="27" selection-start-line="27" selection-end-line="34" selection-end-column="1" />
+        </state>
+      </provider>
+    </entry>
+    <entry file="file://$PROJECT_DIR$/singleton/starving-loading.go">
+      <provider selected="true" editor-type-id="text-editor">
+        <state relative-caret-position="68">
+          <caret line="9" selection-start-line="9" selection-end-line="31" />
+        </state>
+      </provider>
+    </entry>
+    <entry file="file://$PROJECT_DIR$/singleton/double-check-lock.go">
+      <provider selected="true" editor-type-id="text-editor">
+        <state relative-caret-position="120">
+          <caret line="11" selection-start-line="11" selection-end-line="33" selection-end-column="1" />
+          <folding>
+            <element signature="e#14#39#0" expanded="true" />
+          </folding>
+        </state>
+      </provider>
+    </entry>
+    <entry file="file://$PROJECT_DIR$/singleton/README.md">
+      <provider selected="true" editor-type-id="split-provider[text-editor;markdown-preview-editor]">
+        <state split_layout="SPLIT">
+          <first_editor relative-caret-position="426">
+            <caret line="194" column="59" selection-start-line="194" selection-start-column="59" selection-end-line="194" selection-end-column="59" />
+          </first_editor>
+          <second_editor />
+        </state>
+      </provider>
+    </entry>
+  </component>
+</project>
\ No newline at end of file
diff --git a/README.md b/README.md
index f07525b..5198714 100644
--- a/README.md
+++ b/README.md
@@ -1,2 +1,55 @@
 # golang-design-patterns
-使用golang实现各种设计模式
+
+## 使用golang实现各种设计模式
+
+- 创建型模式
+
+  1. [单例模式]()
+
+  2. 工厂方法模式
+
+  3. 抽象工厂模式
+  
+  4. 建造者模式
+  
+  5. 原型模式 
+
+- 行为型模式
+
+  1. 访问者模式
+  
+  2. 模板模式
+  
+  3. 策略模式
+  
+  4. 状态模式
+  
+  5. 观察者模式
+  
+  6. 备忘录模式
+  
+  7. 中介者模式
+  
+  8. 迭代器模式
+  
+  9. 解释器模式
+  
+  10. 命令模式
+  
+  11. 责任链模式
+
+- 结构型模式
+
+  1. 适配器模式
+  
+  2. 桥接模式
+  
+  3. 组合模式
+  
+  4. 装饰模式
+  
+  5. 外观模式
+  
+  6. 亨元模式
+  
+  7. 代理模式
\ No newline at end of file
diff --git a/singleton/README.md b/singleton/README.md
new file mode 100644
index 0000000..4e14a0f
--- /dev/null
+++ b/singleton/README.md
@@ -0,0 +1,196 @@
+# 单例模式
+
+> wiki百科: 单例模式，也叫单子模式，是一种常用的软件设计模式。在应用这个模式时，单例对象的类必须保证只有一个实例存在。许多时候整个系统只需要拥有一个的全局对象，这样有利于我们协调系统整体的行为。比如在某个服务器程序中，该服务器的配置信息存放在一个文件中，这些配置数据由一个单例对象统一读取，然后服务进程中的其他对象再通过这个单例对象获取这些配置信息。这种方式简化了在复杂环境下的配置管理。
+
+
+单例模式要实现的效果就是，对于应用单例模式的类，整个程序中只存在一个实例化对象
+
+go并不是一种面向对象的语言，所以我们使用结构体来替代
+
+有几种方式:
+
+  - 懒汉模式
+  
+  - 饿汉模式
+  
+  - 双重检查锁机制
+
+下面拆分讲解：
+
+### 懒汉模式
+
+1. 构建一个示例结构体
+
+  ```go
+     type example struct {
+     	name string
+     }
+  ```
+2. 设置一个私有变量作为每次要返回的单例
+
+  ```go
+    var instance *example
+  ```
+  
+3. 写一个可以获取单例的方法
+
+  ```go
+      func GetExample() *example {
+      
+      	// 存在线程安全问题，高并发时有可能创建多个对象
+      	if instance == nil {
+      		instance = new(example)
+      	}
+      	return instance
+      }
+  ```
+  
+4. 测试一下
+
+   ```go
+     func main() {
+     	s := GetExample()
+     	s.name = "第一次赋值单例模式"
+     	fmt.Println(s.name)
+     
+     	s2 := GetExample()
+     	fmt.Println(s2.name)
+     }
+   ```
+   
+懒汉模式存在线程安全问题，在第3步的时候，如果有多个线程同时调用了这个方法，
+那么都会检测到`instance`为`nil`,就会创建多个对象，所以出现了饿汉模式...
+
+
+### 饿汉模式
+
+与懒汉模式类似，不再多说，直接上代码
+
+```go
+
+  // 构建一个结构体，用来实例化单例
+  type example2 struct {
+  	name string
+  }
+  
+  // 声明一个私有变量，作为单例
+  var instance2 *example2
+  
+  // init函数将在包初始化时执行，实例化单例
+  func init() {
+  	instance2 = new(example2)
+  	instance2.name = "初始化单例模式"
+  }
+  
+  func GetInstance2() *example2 {
+  	return instance2
+  }
+  
+  func main() {
+  	s := GetInstance2()
+  	fmt.Println(s.name)
+  }
+
+``` 
+
+饿汉模式将在包加载的时候就创建单例对象，当程序中用不到该对象时，浪费了一部分空间
+
+和懒汉模式相比，更安全，但是会减慢程序启动速度
+
+
+### 双重检查机制
+
+懒汉模式存在线程安全问题，一般我们使用互斥锁来解决有可能出现的数据不一致问题 
+
+所以修改上面的`GetInstance()` 方法如下:
+
+```go
+   var mux Sync.Mutex
+   func GetInstance() *example {
+       mux.Lock()                    
+       defer mux.Unlock()
+       if instance == nil {
+           instance = &example{}
+       }
+      return instance
+   }
+```
+
+如果这样去做，每一次请求单例的时候，都会加锁和减锁，而锁的用处只在于解决对象初始化的时候可能出现的并发问题
+当对象被创建之后，加锁就失去了意义，会拖慢速度，所以我们就引入了双重检查机制（`Check-lock-Check`）,
+也叫`DCL`(`Double Check Lock`), 代码如下:
+
+```go
+  func GetInstance() *example {
+      if instance == nil {  // 单例没被实例化，才会加锁 
+          mux.Lock()
+          defer mux.Unlock()
+          if instance == nil {  // 单例没被实例化才会创建
+  	            instance = &example{}
+          }
+      }
+      return instance
+  }
+```
+
+这样只有当对象未初始化的时候，才会又加锁和减锁的操作
+
+但是又出现了另一个问题：每一次访问都要检查两次，为了解决这个问题，我们可以使用golang标准包中的方法进行原子性操作:
+
+```go
+   import "sync"  
+   import "sync/atomic"
+   
+   var initialized uint32
+   
+   func GetInstance() *example {
+   	
+   	  // 一次判断即可返回
+      if atomic.LoadUInt32(&initialized) == 1 {
+   		return instance
+   	   }
+       mux.Lock()
+       defer mux.Unlock()
+       if initialized == 0 {
+            instance = &example{}
+            atomic.StoreUint32(&initialized, 1) // 原子装载
+   	}
+   	return instance
+   }
+```
+以上代码只需要经过一次判断即可返回单例，但是golang标准包中其实给我们提供了相关的方法:
+
+`sync.Once`的`Do`方法可以实现在程序运行过程中只运行一次其中的回调，所以最终简化的代码如下:
+
+```go
+
+ type example3 struct {
+ 	name string
+ }
+ 
+ var instance3 *example3
+ var once sync.Once
+ 
+ func GetInstance3() *example3 {
+ 
+ 	once.Do(func() {
+ 		instance3 = new(example3)
+ 		instance3.name = "第一次赋值单例"
+ 	})
+ 	return instance3
+ }
+ 
+ func main() {
+ 	e1 := GetInstance3()
+ 	fmt.Println(e1.name)
+ 
+ 	e2 := GetInstance3()
+ 	fmt.Println(e2.name)
+ }
+```
+
+单例模式是开发中经常用到的设计模式，我在制作自己的web框架 [silsuer/bingo](https://github.com/silsuer/bingo) 的时候
+在环境变量控制、配置项控制等位置都用到了这种模式。
+
+想把所有设计模式使用golang实现一遍，开了个新坑[silsuer/golang-design-patterns](https://github.com/silsuer/golang-design-patterns),
+这是第一篇，以后会陆续更新，需要请自取～
\ No newline at end of file
diff --git a/singleton/double-check-lock.go b/singleton/double-check-lock.go
new file mode 100644
index 0000000..2ef57d1
--- /dev/null
+++ b/singleton/double-check-lock.go
@@ -0,0 +1,34 @@
+package main
+
+import (
+	"sync"
+	"fmt"
+)
+
+/*
+ * 双重锁检查机制
+ */
+
+type example3 struct {
+	name string
+}
+
+var instance3 *example3
+var once sync.Once
+
+func GetInstance3() *example3 {
+
+	once.Do(func() {
+		instance3 = new(example3)
+		instance3.name = "第一次赋值单例"
+	})
+	return instance3
+}
+
+func main() {
+	e1 := GetInstance3()
+	fmt.Println(e1.name)
+
+	e2 := GetInstance3()
+	fmt.Println(e2.name)
+}
diff --git a/singleton/lazy-loading.go b/singleton/lazy-loading.go
new file mode 100644
index 0000000..f203d6d
--- /dev/null
+++ b/singleton/lazy-loading.go
@@ -0,0 +1,35 @@
+package main
+
+import "fmt"
+
+/*
+ * 单例模式之懒汉模式
+ * 非线程安全
+ */
+
+// 首先构造一个结构体
+type example struct {
+	name string
+}
+
+// 设置一个变量作为单例变量，这是一个私有变量，包外不可访问
+var instance *example
+
+// 写一个方法用来返回单例
+func GetExample() *example {
+
+	// 存在线程安全问题，高并发时有可能创建多个对象
+	if instance == nil {
+		instance = new(example)
+	}
+	return instance
+}
+
+func main() {
+	s := GetExample()
+	s.name = "第一次赋值单例模式"
+	fmt.Println(s.name)
+
+	s2 := GetExample()
+	fmt.Println(s2.name)
+}
diff --git a/singleton/starving-loading.go b/singleton/starving-loading.go
new file mode 100644
index 0000000..2bd84a3
--- /dev/null
+++ b/singleton/starving-loading.go
@@ -0,0 +1,31 @@
+package main
+
+import "fmt"
+
+/*
+ * 饿汉模式
+ * 在类加载时就初始化对象
+ */
+
+// 构建一个结构体，用来实例化单例
+type example2 struct {
+	name string
+}
+
+// 声明一个私有变量，作为单例
+var instance2 *example2
+
+// init函数将在包初始化时执行，实例化单例
+func init() {
+	instance2 = new(example2)
+	instance2.name = "初始化单例模式"
+}
+
+func GetInstance2() *example2 {
+	return instance2
+}
+
+func main() {
+	s := GetInstance2()
+	fmt.Println(s.name)
+}