samples/cpp/tutorial_code/core/file_input_output/file_input_output.cpp

一个使用 FileStorage 接口的完整示例。有关更多详细信息，请参见 相应的教程。

#include <opencv2/core.hpp>
#include <iostream>
#include <string>
 
using namespace cv;
using namespace std;
 
static void help(char** av)
{
cout << endl
<< av[0] << " 展示了 OpenCV 序列化功能的用法。" << endl << endl
<< "用法: " << endl
<< av[0] << " [输出文件名] (默认输出文件为 outputfile.yml.gz)" << endl << endl
<< "输出文件可以是 XML (xml)、YAML (yml/yaml) 或 JSON (json)。" << endl
<< "您甚至可以通过在其扩展名中指定来压缩它，例如 xml.gz yaml.gz 等..." << endl
<< "使用 FileStorage，您可以通过使用 << 和 >> 运算符来序列化 OpenCV 中的对象" << endl
<< "例如: - 创建一个类并对其进行序列化" << endl
<< " - 使用它来读写矩阵。" << endl << endl;
}
 
class MyData
{
public:
MyData() : A(0), X(0), id()
    {}
    explicit MyData(int) : A(97), X(CV_PI), id("mydata1234") // explicit to avoid implicit conversion
    {}
    void write(FileStorage& fs) const //Write serialization for this class
    {
fs << "{" << "A" << A << "X" << X << "id" << id << "}";
    }
    void read(const FileNode& node) //Read serialization for this class
    {
A = (int)node["A"];
X = (double)node["X"];
        id = (string)node["id"];
    }
public: // Data Members
    int A;
    double X;
    string id;
};
 
//These write and read functions must be defined for the serialization in FileStorage to work
static void write(FileStorage& fs, const std::string&, const MyData& x)
{
x.write(fs);
}
static void read(const FileNode& node, MyData& x, const MyData& default_value = MyData()){
    if(node.empty())
x = default_value;
    else
x.read(node);
}
 
// This function will print our custom class to the console
static ostream& operator<<(ostream& out, const MyData& m)
{
out << "{ id = " << m.id << ", ";
out << "X = " << m.X << ", ";
out << "A = " << m.A << "}";
    return out;
}
 
int main(int ac, char** av)
{
    string filename;
 
    if (ac != 2)
    {
help(av);
filename = "outputfile.yml.gz";
    }
    else
filename = av[1];
 
{ //write
        Mat R = Mat_<uchar>::eye(3, 3),
T = Mat_<double>::zeros(3, 1);
MyData m(1);
 
        FileStorage fs(filename, FileStorage::WRITE);
        // 或
        // FileStorage fs;
        // fs.open(filename, FileStorage::WRITE);
 
fs << "iterationNr" << 100;
fs << "strings" << "["; // text - string sequence
fs << "image1.jpg" << "Awesomeness" << "../data/baboon.jpg";
fs << "]"; // close sequence
 
fs << "Mapping"; // text - mapping
fs << "{" << "One" << 1;
fs << "Two" << 2 << "}";
 
fs << "R" << R; // cv::Mat
fs << "T" << T;
 
fs << "MyData" << m; // your own data structures
 
fs.release(); // explicit close
cout << "写入文件:" << filename << " 操作已成功完成。" << endl;
    }
 
{//read
cout << endl << "正在读取: " << endl;
        FileStorage fs;
fs.open(filename, FileStorage::READ);
 
        int itNr;
        //fs["iterationNr"] >> itNr;
itNr = (int) fs["iterationNr"];
cout << itNr;
        if (!fs.isOpened())
        {
cerr << "无法打开 " << filename << endl;
help(av);
            return 1;
        }
 
        FileNode n = fs["strings"]; // Read string sequence - Get node
        if (n.type() != FileNode::SEQ)
        {
cerr << "strings 不是序列！失败" << endl;
            return 1;
        }
 
        FileNodeIterator it = n.begin(), it_end = n.end(); // Go through the node
        for (; it != it_end; ++it)
cout << (string)*it << endl;
 
 
n = fs["Mapping"]; // Read mappings from a sequence
cout << "Two " << (int)(n["Two"]) << "; ";
cout << "One " << (int)(n["One"]) << endl << endl;
 
 
MyData m;
        Mat R, T;
 
fs["R"] >> R; // Read cv::Mat
fs["T"] >> T;
fs["MyData"] >> m; // Read your own structure_
 
cout << endl
<< "R = " << R << endl;
cout << "T = " << T << endl << endl;
cout << "MyData = " << endl << m << endl << endl;
 
        //Show default behavior for non existing nodes
cout << "尝试读取 NonExisting (应该使用其默认值初始化数据结构)。";
fs["NonExisting"] >> m;
cout << endl << "NonExisting = " << endl << m << endl;
    }
 
cout << endl
<< "提示: 用文本编辑器打开 " << filename << " 来查看序列化数据。" << endl;
 
    return 0;
}