class="markdown_views prism-atom-one-dark">

使用nlohmann的库

“安装”

把include下载到本地可以include的位置

demo

需要再class="tags" href="/STRUCT.html" title=struct>struct和class中实现to_class="tags" href="/JSON.html" title=json>json()和from_class="tags" href="/JSON.html" title=json>json()函数。

貌似cpp20可以通过反射无需手动编写to_class="tags" href="/JSON.html" title=json>json()和from_class="tags" href="/JSON.html" title=json>json()，这里不做展开

class="prism language-cpp">class="token macro property">class="token directive-hash">#class="token directive keyword">include class="token string"><iostream>
class="token macro property">class="token directive-hash">#class="token directive keyword">include class="token string">"nlohmann/class="tags" href="/JSON.html" title=json>json.hpp"class="token keyword">using nlohmannclass="token double-colon punctuation">::class="tags" href="/JSON.html" title=json>jsonclass="token punctuation">;class="token keyword">class="tags" href="/STRUCT.html" title=struct>struct class="token class-name">Dog class="token punctuation">{stdclass="token double-colon punctuation">::string Nameclass="token punctuation">;class="token comment">// to_class="tags" href="/JSON.html" title=json>json 和 from_class="tags" href="/JSON.html" title=json>json 需要在同一命名空间下class="token keyword">void class="token function">to_class="tags" href="/JSON.html" title=json>jsonclass="token punctuation">(class="tags" href="/JSON.html" title=json>jsonclass="token operator">& jclass="token punctuation">)class="token punctuation">{jclass="token punctuation">[class="token string">"Name"class="token punctuation">] class="token operator">= Nameclass="token punctuation">;class="token punctuation">}class="token keyword">void class="token function">from_class="tags" href="/JSON.html" title=json>jsonclass="token punctuation">(class="token keyword">const class="tags" href="/JSON.html" title=json>jsonclass="token operator">& jclass="token punctuation">)class="token punctuation">{jclass="token punctuation">.class="token function">atclass="token punctuation">(class="token string">"Name"class="token punctuation">)class="token punctuation">.class="token function">get_toclass="token punctuation">(Nameclass="token punctuation">)class="token punctuation">;class="token punctuation">}
class="token punctuation">}class="token punctuation">;class="token keyword">class="tags" href="/STRUCT.html" title=struct>struct class="token class-name">Phone class="token punctuation">{stdclass="token double-colon punctuation">::string Ptypeclass="token punctuation">;class="token keyword">int Pnumclass="token punctuation">;class="token comment">// to_class="tags" href="/JSON.html" title=json>json 和 from_class="tags" href="/JSON.html" title=json>json 需要在同一命名空间下class="token keyword">void class="token function">to_class="tags" href="/JSON.html" title=json>jsonclass="token punctuation">(class="tags" href="/JSON.html" title=json>jsonclass="token operator">& jclass="token punctuation">)class="token punctuation">{j class="token operator">= class="token punctuation">{class="token punctuation">{class="token string">"Ptype"class="token punctuation">, Ptypeclass="token punctuation">}class="token punctuation">,class="token punctuation">{class="token string">"Pnum"class="token punctuation">,Pnumclass="token punctuation">}class="token punctuation">}class="token punctuation">;class="token punctuation">}class="token keyword">void class="token function">from_class="tags" href="/JSON.html" title=json>jsonclass="token punctuation">(class="token keyword">const class="tags" href="/JSON.html" title=json>jsonclass="token operator">& jclass="token punctuation">)class="token punctuation">{jclass="token punctuation">.class="token function">atclass="token punctuation">(class="token string">"Ptype"class="token punctuation">)class="token punctuation">.class="token function">get_toclass="token punctuation">(Ptypeclass="token punctuation">)class="token punctuation">;jclass="token punctuation">.class="token function">atclass="token punctuation">(class="token string">"Pnum"class="token punctuation">)class="token punctuation">.class="token function">get_toclass="token punctuation">(Pnumclass="token punctuation">)class="token punctuation">;class="token punctuation">}
class="token punctuation">}class="token punctuation">;class="token keyword">class="tags" href="/STRUCT.html" title=struct>struct class="token class-name">User class="token punctuation">{stdclass="token double-colon punctuation">::string Nameclass="token punctuation">;class="token keyword">int Ageclass="token punctuation">;stdclass="token double-colon punctuation">::mapclass="token operator"><stdclass="token double-colon punctuation">::stringclass="token punctuation">, class="token keyword">intclass="token operator">> Scoreclass="token punctuation">;stdclass="token double-colon punctuation">::mapclass="token operator"><stdclass="token double-colon punctuation">::stringclass="token punctuation">, Dogclass="token operator">> Petsclass="token punctuation">;Phone MPhoneclass="token punctuation">;class="token comment">// to_class="tags" href="/JSON.html" title=json>json 和 from_class="tags" href="/JSON.html" title=json>json 需要在同一命名空间下class="token keyword">void class="token function">to_class="tags" href="/JSON.html" title=json>jsonclass="token punctuation">(class="tags" href="/JSON.html" title=json>jsonclass="token operator">& jclass="token punctuation">)class="token punctuation">{j class="token operator">= class="tags" href="/JSON.html" title=json>jsonclass="token punctuation">{class="token punctuation">{class="token string">"Name"class="token punctuation">, Nameclass="token punctuation">}class="token punctuation">, class="token punctuation">{class="token string">"Age"class="token punctuation">, Ageclass="token punctuation">}class="token punctuation">}class="token punctuation">;MPhoneclass="token punctuation">.class="token function">to_class="tags" href="/JSON.html" title=json>jsonclass="token punctuation">(jclass="token punctuation">[class="token string">"MPhone"class="token punctuation">]class="token punctuation">)class="token punctuation">;    class="token comment">// 对象属性to_class="tags" href="/JSON.html" title=json>jsonclass="token keyword">for class="token punctuation">(class="token keyword">autoclass="token operator">& pair class="token operator">: Petsclass="token punctuation">) class="token punctuation">{pairclass="token punctuation">.secondclass="token punctuation">.class="token function">to_class="tags" href="/JSON.html" title=json>jsonclass="token punctuation">(jclass="token punctuation">[class="token string">"Pets"class="token punctuation">]class="token punctuation">[pairclass="token punctuation">.firstclass="token punctuation">]class="token punctuation">)class="token punctuation">; class="token comment">// map+对象class="token punctuation">}class="token keyword">for class="token punctuation">(class="token keyword">const class="token keyword">autoclass="token operator">& pair class="token operator">: Scoreclass="token punctuation">) class="token punctuation">{    class="token comment">// map+intjclass="token punctuation">[class="token string">"Score"class="token punctuation">]class="token punctuation">[pairclass="token punctuation">.firstclass="token punctuation">] class="token operator">= pairclass="token punctuation">.secondclass="token punctuation">;class="token punctuation">}class="token punctuation">}class="token keyword">void class="token function">from_class="tags" href="/JSON.html" title=json>jsonclass="token punctuation">(class="token keyword">const class="tags" href="/JSON.html" title=json>jsonclass="token operator">& jclass="token punctuation">)class="token punctuation">{jclass="token punctuation">.class="token function">atclass="token punctuation">(class="token string">"Name"class="token punctuation">)class="token punctuation">.class="token function">get_toclass="token punctuation">(Nameclass="token punctuation">)class="token punctuation">;jclass="token punctuation">.class="token function">atclass="token punctuation">(class="token string">"Age"class="token punctuation">)class="token punctuation">.class="token function">get_toclass="token punctuation">(Ageclass="token punctuation">)class="token punctuation">;class="token keyword">ifclass="token punctuation">(jclass="token punctuation">.class="token function">containsclass="token punctuation">(class="token string">"Pets"class="token punctuation">)class="token punctuation">)class="token punctuation">{class="token keyword">for class="token punctuation">(class="token keyword">const class="token keyword">autoclass="token operator">& pair class="token operator">: jclass="token punctuation">.class="token function">atclass="token punctuation">(class="token string">"Pets"class="token punctuation">)class="token punctuation">.class="token function">itemsclass="token punctuation">(class="token punctuation">)class="token punctuation">) class="token punctuation">{Petsclass="token punctuation">[pairclass="token punctuation">.class="token function">keyclass="token punctuation">(class="token punctuation">)class="token punctuation">] class="token operator">= class="token function">Dogclass="token punctuation">(class="token punctuation">)class="token punctuation">;Petsclass="token punctuation">[pairclass="token punctuation">.class="token function">keyclass="token punctuation">(class="token punctuation">)class="token punctuation">]class="token punctuation">.class="token function">from_class="tags" href="/JSON.html" title=json>jsonclass="token punctuation">(pairclass="token punctuation">.class="token function">valueclass="token punctuation">(class="token punctuation">)class="token punctuation">)class="token punctuation">;class="token punctuation">}class="token punctuation">}class="token keyword">for class="token punctuation">(class="token keyword">const class="token keyword">autoclass="token operator">& pair class="token operator">: jclass="token punctuation">.class="token function">atclass="token punctuation">(class="token string">"Score"class="token punctuation">)class="token punctuation">.class="token function">itemsclass="token punctuation">(class="token punctuation">)class="token punctuation">) class="token punctuation">{  Scoreclass="token punctuation">[pairclass="token punctuation">.class="token function">keyclass="token punctuation">(class="token punctuation">)class="token punctuation">] class="token operator">= pairclass="token punctuation">.class="token function">valueclass="token punctuation">(class="token punctuation">)class="token punctuation">;  class="token punctuation">}class="token punctuation">}class="token keyword">void class="token function">from_class="tags" href="/JSON.html" title=json>jsonclass="token punctuation">(stdclass="token double-colon punctuation">::string class="tags" href="/JSON.html" title=json>json_strclass="token punctuation">)class="token punctuation">{class="tags" href="/JSON.html" title=json>json j class="token operator">= class="tags" href="/JSON.html" title=json>jsonclass="token double-colon punctuation">::class="token function">parseclass="token punctuation">(class="tags" href="/JSON.html" title=json>json_strclass="token punctuation">)class="token punctuation">;class="token function">from_class="tags" href="/JSON.html" title=json>jsonclass="token punctuation">(jclass="token punctuation">)class="token punctuation">;class="token punctuation">}
class="token punctuation">}class="token punctuation">;class="token keyword">int class="token function">mainclass="token punctuation">(class="token punctuation">)class="token punctuation">{User userclass="token punctuation">;userclass="token punctuation">.Name class="token operator">= class="token string">"zhangsi"class="token punctuation">;userclass="token punctuation">.Age class="token operator">= class="token number">25class="token punctuation">;Phone pclass="token punctuation">{class="token string">"Mi"class="token punctuation">, class="token number">1234class="token punctuation">}class="token punctuation">;userclass="token punctuation">.MPhone class="token operator">= pclass="token punctuation">;userclass="token punctuation">.Scoreclass="token punctuation">[class="token string">"math"class="token punctuation">] class="token operator">= class="token number">88class="token punctuation">;userclass="token punctuation">.Scoreclass="token punctuation">[class="token string">"art"class="token punctuation">] class="token operator">= class="token number">89class="token punctuation">;userclass="token punctuation">.Petsclass="token punctuation">[class="token string">"大黄"class="token punctuation">] class="token operator">= Dogclass="token punctuation">{class="token string">"大黄"class="token punctuation">}class="token punctuation">;userclass="token punctuation">.Petsclass="token punctuation">[class="token string">"小黑"class="token punctuation">] class="token operator">= Dogclass="token punctuation">{class="token string">"小黑"class="token punctuation">}class="token punctuation">;class="tags" href="/JSON.html" title=json>json jclass="token punctuation">;userclass="token punctuation">.class="token function">to_class="tags" href="/JSON.html" title=json>jsonclass="token punctuation">(jclass="token punctuation">)class="token punctuation">;stdclass="token double-colon punctuation">::cout class="token operator"><< class="token string">"to_class="tags" href="/JSON.html" title=json>json: " class="token operator"><< jclass="token punctuation">.class="token function">dumpclass="token punctuation">(class="token punctuation">) class="token operator"><< stdclass="token double-colon punctuation">::endlclass="token punctuation">;stdclass="token double-colon punctuation">::cout class="token operator"><< class="token string">"to_class="tags" href="/JSON.html" title=json>json with indent:\n" class="token operator"><< jclass="token punctuation">.class="token function">dumpclass="token punctuation">(class="token number">4class="token punctuation">) class="token operator"><< stdclass="token double-colon punctuation">::endlclass="token punctuation">;User new_userclass="token punctuation">;new_userclass="token punctuation">.class="token function">from_class="tags" href="/JSON.html" title=json>jsonclass="token punctuation">(jclass="token punctuation">)class="token punctuation">;stdclass="token double-colon punctuation">::cout class="token operator"><< class="token string">"\n\nuser from class="tags" href="/JSON.html" title=json>json: User\nName: " class="token operator"><< new_userclass="token punctuation">.Name class="token operator"><< class="token string">"\nAge: " class="token operator"><< new_userclass="token punctuation">.Age class="token operator"><< stdclass="token double-colon punctuation">::endlclass="token punctuation">;class="token punctuation">}