JsonCpp Documentation
法池暝
JasonCpp文档连接：http://jsoncpp.sourceforge.net/index.html
Introduction
JSON (JavaScript Object Notation)
is a lightweight data-interchange format. It can represent integer, real number, string, an ordered sequence of value, and a collection of name/value pairs.
Here is an example of JSON data:
// Configuration options
{
// Default encoding for text
"encoding" : "UTF-8",
// Plug-ins loaded at start-up
"plug-ins" : [
"python",
"c++",
"ruby"
],
// Tab indent size
"indent" : { "length" : 3, "use_space": true }
}
Features
- read and write JSON document
- attach C and C++ style comments to element during parsing
- rewrite JSON document preserving original comments
Notes: Comments used to be supported in JSON but where removed for portability (C like comments are not supported in Python). Since comments are useful in configuration/input file, this feature was preserved.
Code example
Json::Value root; // will contains the root value after parsing.
Json::Reader reader;
bool parsingSuccessful = reader.parse( config_doc, root );
if ( !parsingSuccessful )
{
// report to the user the failure and their locations in the document.
std::cout << "Failed to parse configuration\n"
<< reader.getFormattedErrorMessages();
return;
}
// Get the value of the member of root named 'encoding', return 'UTF-8' if there is no
// such member.
std::string encoding = root.get("encoding", "UTF-8" ).asString();
// Get the value of the member of root named 'encoding', return a 'null' value if
// there is no such member.
const Json::Value plugins = root["plug-ins"];
for ( int index = 0; index < plugins.size(); ++index ) // Iterates over the sequence elements.
loadPlugIn( plugins[index].asString() );
setIndentLength( root["indent"].get("length", 3).asInt() );
setIndentUseSpace( root["indent"].get("use_space", true).asBool() );
// ...
// At application shutdown to make the new configuration document:
// Since Json::Value has implicit constructor for all value types, it is not
// necessary to explicitly construct the Json::Value object:
root["encoding"] = getCurrentEncoding();
root["indent"]["length"] = getCurrentIndentLength();
root["indent"]["use_space"] = getCurrentIndentUseSpace();
Json::StyledWriter writer;
// Make a new JSON document for the configuration. Preserve original comments.
std::string outputConfig = writer.write( root );
// You can also use streams. This will put the contents of any JSON
// stream at a particular sub-value, if you'd like.
std::cin >> root["subtree"];
// And you can write to a stream, using the StyledWriter automatically.
std::cout << root;
Build instructions
The build instructions are located in the file
README.txt
in the top-directory of the project.
Permanent link to the latest revision of the file in subversion: latest README.txt
Download
The sources can be downloaded from
SourceForge download page
.
The latest version of the source is available in the project's subversion repository: http://jsoncpp.svn.sourceforge.net/svnroot/jsoncpp/trunk/
To checkout the source, see the following instructions.
What's New?
The description of latest changes can be found in
NEWS.txt
in the top-directory of the project.
Permanent link to the latest revision of the file in subversion: latest NEWS.txt
Project links
Related links
- JSON Specification and alternate language implementations.
- YAML A data format designed for human readability.
- UTF-8 and Unicode FAQ.
License
See file
LICENSE
in the top-directory of the project.
Basically JsonCpp is licensed under MIT license, or public domain if desired and recognized in your jurisdiction.
Introduction
JSON (JavaScript Object Notation) is a lightweight data-interchange format. It can represent integer, real number, string, an ordered sequence of value, and a collection of name/value pairs.Here is an example of JSON data:
// Configuration options
{
// Default encoding for text
"encoding" : "UTF-8",
// Plug-ins loaded at start-up
"plug-ins" : [
"python",
"c++",
"ruby"
],
// Tab indent size
"indent" : { "length" : 3, "use_space": true }
}
Features
- read and write JSON document
- attach C and C++ style comments to element during parsing
- rewrite JSON document preserving original comments
Notes: Comments used to be supported in JSON but where removed for portability (C like comments are not supported in Python). Since comments are useful in configuration/input file, this feature was preserved.
Code example
Json::Value root; // will contains the root value after parsing. Json::Reader reader; bool parsingSuccessful = reader.parse( config_doc, root ); if ( !parsingSuccessful ) { // report to the user the failure and their locations in the document. std::cout << "Failed to parse configuration\n" << reader.getFormattedErrorMessages(); return; } // Get the value of the member of root named 'encoding', return 'UTF-8' if there is no // such member. std::string encoding = root.get("encoding", "UTF-8" ).asString(); // Get the value of the member of root named 'encoding', return a 'null' value if // there is no such member. const Json::Value plugins = root["plug-ins"]; for ( int index = 0; index < plugins.size(); ++index ) // Iterates over the sequence elements. loadPlugIn( plugins[index].asString() ); setIndentLength( root["indent"].get("length", 3).asInt() ); setIndentUseSpace( root["indent"].get("use_space", true).asBool() ); // ... // At application shutdown to make the new configuration document: // Since Json::Value has implicit constructor for all value types, it is not // necessary to explicitly construct the Json::Value object: root["encoding"] = getCurrentEncoding(); root["indent"]["length"] = getCurrentIndentLength(); root["indent"]["use_space"] = getCurrentIndentUseSpace(); Json::StyledWriter writer; // Make a new JSON document for the configuration. Preserve original comments. std::string outputConfig = writer.write( root ); // You can also use streams. This will put the contents of any JSON // stream at a particular sub-value, if you'd like. std::cin >> root["subtree"]; // And you can write to a stream, using the StyledWriter automatically. std::cout << root;
Build instructions
The build instructions are located in the file README.txt in the top-directory of the project.Permanent link to the latest revision of the file in subversion: latest README.txt
Download
The sources can be downloaded from SourceForge download page .The latest version of the source is available in the project's subversion repository: http://jsoncpp.svn.sourceforge.net/svnroot/jsoncpp/trunk/
To checkout the source, see the following instructions.
What's New?
The description of latest changes can be found in NEWS.txt in the top-directory of the project.Permanent link to the latest revision of the file in subversion: latest NEWS.txt
Project links
Related links
- JSON Specification and alternate language implementations.
- YAML A data format designed for human readability.
- UTF-8 and Unicode FAQ.
License
See file LICENSE in the top-directory of the project.Basically JsonCpp is licensed under MIT license, or public domain if desired and recognized in your jurisdiction.
类似资料：