用opencv对YAML或XML的操作分为两种操作，操作与所对应的opencv类如下：
输入数据 ：FileStorag；
输出数据 ：FileStorag ，FileNode ，FileNodeIterator；
因为对YAML与XML的操作都是一样的，只是读取文件时前者后缀是 .yaml 后者是 .xml，所以在这只举例对YAML操作，输入的数据类型有一般常类型（如int），矩阵，序列（vector），maps和自定义的类。不管是输入还是输出数据都是通过键值的方式，输入时先输入键再输入对应的值，输出时是由键索引值，通过下面代码会容易理解。
1.输入数据
数据有：
整型 int 100 ;
矩阵 Mat R = Mat_<uchar>::eye(3, 3),T = Mat_<double>::zeros(3, 1);
序列 ["image1.jpg" ，"Awesomeness" ，"baboon.jpg"]；
maps {One:1,Two:2 };
自定义类 MyData m(1);//类的具体定义在下面代码中给出
代码：
string filename = "E:\\test.yaml"; FileStorage fs; fs.open(filename,FileStorage::WRITE); //输入100 fs << "iterationNr" << 100; //输入序列 fs << "strings" << "["; fs << "image1.jpg" << "Awesomeness" << "baboon.jpg"; fs << "]"; //输入maps fs << "Mapping"; fs << "{" << "One" << 1; fs << "Two" << 2 << "}"; //输入矩阵 fs << "R" << R; fs << "T" << T; //输入自定义类 fs << "MyData" << m; fs.release();2.输出数据
代码：
FileStorage fs; fs.open(filename, FileStorage::READ); int itNr; //fs["iterationNr"] >> itNr; itNr = (int) fs["iterationNr"]; cout << itNr; if (!fs.isOpened()) { cerr << "Failed to open " << filename << endl; return 1; } //获取节点 FileNode n = fs["strings"]; if (n.type() != FileNode::SEQ) { cerr << "strings is not a sequence! FAIL" << endl; return 1; } //遍历序列输出各元素 FileNodeIterator it = n.begin(), it_end = n.end(); for (; it != it_end; ++it) cout << (string)*it << endl; //遍历maps输出各元素 n = fs["Mapping"]; cout << "Two " << (int)(n["Two"]) << "; "; cout << "One " << (int)(n["One"]) << endl << endl; MyData m; Mat R, T; //输出矩阵 fs["R"] >> R; fs["T"] >> T; //输出自定义类 fs["MyData"] >> m;当打开文件时，会使用FileStorag类的一个open()函数，这个函数中的第一个参数是文件名路径，第二个参数都以常量形式指定你要对文件进行操作的类型，包括：WRITE, READ 或 APPEND。
3.完整的代码如下：
using namespace cv; using namespace std; class MyData { public: MyData() : A(0), X(0), id() {} explicit MyData(int) : A(97), X(CV_PI), id("mydata1234") {} void write(FileStorage& fs) const //将类的数据写入到fs { fs << "{" << "A" << A << "X" << X << "id" << id << "}"; } void read(const FileNode& node) //将node的数据读入类中 { 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 void write(FileStorage& fs, const std::string&, const MyData& x) { x.write(fs);//将x类中的数据写入到fs中 } void read(const FileNode& node, MyData& x, const MyData& default_value = MyData()) { if(node.empty()) x = default_value; else x.read(node);//将node的数据读入到x类中 } // 对<<的重载，将类的属性输出 ostream& operator<<(ostream& out, const MyData& m) { out << "{ id = " << m.id << ", "; out << "X = " << m.X << ", "; out << "A = " << m.A << "}"; return out; } int main() { string filename = "E:\\test.yaml"; { //write Mat R = Mat_<uchar>::eye(3, 3), T = Mat_<double>::zeros(3, 1); MyData m(1); FileStorage fs(filename, FileStorage::WRITE); fs << "iterationNr" << 100; //输入序列 fs << "strings" << "["; fs << "image1.jpg" << "Awesomeness" << "baboon.jpg"; fs << "]"; //输入maps fs << "Mapping"; fs << "{" << "One" << 1; fs << "Two" << 2 << "}"; //输入矩阵 fs << "R" << R; fs << "T" << T; //输入自定义类 fs << "MyData" << m; fs.release(); cout << "Write Done." << endl; } {//read cout << endl << "Reading: " << endl; FileStorage fs; fs.open(filename, FileStorage::READ); int itNr; //fs["iterationNr"] >> itNr; itNr = (int) fs["iterationNr"]; cout << itNr; if (!fs.isOpened()) { cerr << "Failed to open " << filename << endl; return 1; } //获取节点 FileNode n = fs["strings"]; if (n.type() != FileNode::SEQ) { cerr << "strings is not a sequence! FAIL" << endl; return 1; } //遍历序列输出各元素 FileNodeIterator it = n.begin(), it_end = n.end(); for (; it != it_end; ++it) cout << (string)*it << endl; //遍历maps输出各元素 n = fs["Mapping"]; cout << "Two " << (int)(n["Two"]) << "; "; cout << "One " << (int)(n["One"]) << endl << endl; MyData m; Mat R, T; //输出矩阵 fs["R"] >> R; fs["T"] >> T; //输出自定义类 fs["MyData"] >> m; cout << endl << "R = " << R << endl; cout << "T = " << T << endl << endl; cout << "MyData = " << endl << m << endl << endl; //Show default behavior for non existing nodes cout << "Attempt to read NonExisting (should initialize the data structure with its default)."; fs["NonExisting"] >> m; cout << endl << "NonExisting = " << endl << m << endl; } cout << endl << "Tip: Open up " << filename << " with a text editor to see the serialized data." << endl; return 0; }PS:本人是用Qtcreator创建的程序。
