json文件操作

json文件提供官方提供两个只有头文件的库nlohmann-json和 rapidjson。

nlohmann-json

安装

使用kmpkg一键安装集成：

kmpkg install nlohmann-json
Computing installation plan...
The following packages will be built and installed:
    nlohmann-json:x64-linux@3.11.3#1
Detecting compiler hash for triplet x64-linux...
Compiler found: /bin/c++
Restored 1 package(s) from /home/jeff/.cache/kmpkg/archives in 7.4 ms. Use --debug to see more details.
Installing 1/1 nlohmann-json:x64-linux@3.11.3#1...
Elapsed time to handle nlohmann-json:x64-linux: 11.5 ms
nlohmann-json:x64-linux package ABI: b78a3e89712d3a4abdc98ea97493983540eafb33365c2317df8ec37b68aee131
Total install time: 11.5 ms
The package nlohmann-json provides CMake targets:

    find_package(nlohmann_json CONFIG REQUIRED)
    target_link_libraries(main PRIVATE nlohmann_json::nlohmann_json)

The package nlohmann-json can be configured to not provide implicit conversions via a custom triplet file:

    set(nlohmann-json_IMPLICIT_CONVERSIONS OFF)

For more information, see the docs here:

    https://json.nlohmann.me/api/macros/json_use_implicit_conversions/

文档与示例

参与官方文档

rapidjson

安装

使用kmpkg一键安装集成：

kmpkg install rapidjson
Computing installation plan...
The following packages will be built and installed:
    nlohmann-json:x64-linux@3.11.3#1
Detecting compiler hash for triplet x64-linux...
Compiler found: /bin/c++
Restored 1 package(s) from /home/jeff/.cache/kmpkg/archives in 7.4 ms. Use --debug to see more details.
Installing 1/1 nlohmann-json:x64-linux@3.11.3#1...
Elapsed time to handle nlohmann-json:x64-linux: 11.5 ms
nlohmann-json:x64-linux package ABI: b78a3e89712d3a4abdc98ea97493983540eafb33365c2317df8ec37b68aee131
Total install time: 11.5 ms
The package nlohmann-json provides CMake targets:

    find_package(nlohmann_json CONFIG REQUIRED)
    target_link_libraries(main PRIVATE nlohmann_json::nlohmann_json)

The package nlohmann-json can be configured to not provide implicit conversions via a custom triplet file:

    set(nlohmann-json_IMPLICIT_CONVERSIONS OFF)

For more information, see the docs here:

    https://json.nlohmann.me/api/macros/json_use_implicit_conversions/

jeff@jeff-fkumo:~/gitee/kumo-ai/kumo-docs$ kmpkg install rapidjson
Computing installation plan...
The following packages will be built and installed:
    rapidjson:x64-linux@2024-09-04#1
Detecting compiler hash for triplet x64-linux...
Compiler found: /bin/c++
Restored 1 package(s) from /home/jeff/.cache/kmpkg/archives in 6.1 ms. Use --debug to see more details.
Installing 1/1 rapidjson:x64-linux@2024-09-04#1...
Elapsed time to handle rapidjson:x64-linux: 11.7 ms
rapidjson:x64-linux package ABI: 18062329cab92d999d854c185dc90c36e7c36774cbafe2f6a6bfaae591441fc0
Total install time: 11.7 ms
rapidjson provides CMake targets:

  # this is heuristically generated, and may not be correct
  find_package(RapidJSON CONFIG REQUIRED)
  target_link_libraries(main PRIVATE RapidJSON)

rapidjson provides pkg-config modules:

  # A fast JSON parser/generator for C++ with both SAX/DOM style API
  RapidJSON

文档与示例

参与官方文档

使用建议

github上有专题专门针对json个的表现做了总结，这里给出结论

• 对内存、性能要求苛刻的应用请使用rapidjson，虽然API有些奇怪。
• 对性能要求并非很高，或者解析json的频次并非很高的场景，建议实用nlohmann-json，它的API设计更人性化，会大幅度提升 开发体验和开发效率。