471 lines
12 KiB
Markdown
471 lines
12 KiB
Markdown
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x2struct
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====
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* 用于在C++结构体和json/xml/json/libconfig之间互相转换
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* json/xml只需要头文件, 无需编译库文件
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* json缺省支持，其他的需要修改[config.h](config.h)开启相应功能
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* 以下例子全部以json为例，其他的类似，具体可以参考[x2struct.hpp](x2struct.hpp)里面x2struct::X的api定义
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------
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* [基本用法](#基本用法)
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* [必需节点](#必需节点)
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* [别名](#别名)
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* [继承](#继承)
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* [位域](#位域)
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* [条件加载](#条件加载)
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* [char数组](#char数组)
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* [检查是否存在](#检查是否存在)
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* [局部类](#局部类)
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* [自定义类型](#自定义类型)
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* [第三方类和结构体](#第三方类和结构体)
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* [格式化缩进](#格式化缩进)
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* [xml bson libconfig](#xml-bson-libconfig)
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* [生成Golang结构体](#生成golang结构体)
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* [重要说明](#重要说明)
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基本用法
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----
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```C++
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#include <iostream>
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#include "x2struct/x2struct.hpp" // 包含这个头文件
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using namespace std;
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struct User {
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int64_t id;
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string name;
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string mail;
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User(int64_t i=0, const string& n="", const string& m=""):id(i),name(n),mail(m){}
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XTOSTRUCT(O(id, name, mail)); // 添加宏定义XTOSTRUCT在结构体定义结尾
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};
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struct Group {
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string name;
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int64_t master;
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vector<User> members;
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XTOSTRUCT(O(name, master, members)); // 添加宏定义XTOSTRUCT在结构体定义结尾
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};
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int main(int argc, char *argv[]) {
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Group g;
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g.name = "C++";
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g.master = 2019;
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g.members.resize(2);
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g.members[0] = User(1, "Jack", "jack@x2struct.com");
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g.members[1] = User(2, "Pony", "pony@x2struct.com");
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string json = x2struct::X::tojson(g); // 结构体转json
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cout<<json<<endl;
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Group n;
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x2struct::X::loadjson(json, n, false); // json转结构体
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cout<<n.name<<endl;
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vector<int> vi;
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x2struct::X::loadjson("[1,2,3]", vi, false); // 直接加载vector
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cout<<vi.size()<<','<<vi[1]<<endl;
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map<int, int> m;
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x2struct::X::loadjson("{\"1\":10, \"2\":20}", m, false); // 直接加载map
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cout<<m.size()<<','<<m[2]<<endl;
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return 0;
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}
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```
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步骤有：
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- 引用头文件 "x2struct.hpp"
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- 添加宏定义XTOSTRUCT在结构体结尾, 里面用"O"包含所有变量
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- 用x2struct::X::tojson将结构体转json
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- 用x2struct::X::loadjson将json转结构体
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必需节点
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----
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- 用于在json转结构体的时候，某些key是要求必须存在的
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- 用"M"来包含必需节点的变量
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- 如果json里面没有这些key，转结构体的时候会抛出异常
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```C++
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#include <iostream>
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#include "x2struct/x2struct.hpp"
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using namespace std;
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struct Test {
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int64_t id;
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string name;
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XTOSTRUCT(M(id), O(name)); // "id"是必需节点，用M包含，"name"是可选节点，用"O"包含
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};
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int main(int argc, char *argv[]) {
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Test t;
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string json="{\"name\":\"Pony\"}";
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x2struct::X::loadjson(json, t, false); // 这里将会抛异常，因为"id"是必需节点，但是json里面没有
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return 0;
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}
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```
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别名
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----
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- 用于变量名和key名不一致的场景
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- 用"A"包含需要设置别名的变量，"A"包含两个参数，参数1是变量名，参数2是别名信息
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- 别名段的基本格式是"[type:]alias[,extension]", 别名信息可以包含多个别名段，别名段之间用空格隔开
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- type的值可以是"json"/"xml"/"bson"/"config", 如果别名段没有type这个字段，则表示这个别名段对所有的type生效，例子：
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- "tid" 由于没有type，那么表示所有的type的别名都是"tid"
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- "tid json:xid" "tid"没指定type，xid指定了json，那么json用xid，其他的用tid
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- 扩展字段目前只支持"m"，表示必需节点（缺省是可选）
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- 如果在json里面没有别名，依然会尝试变量名
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- 结构体转json的时候，用别名
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``` C++
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#include <iostream>
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#include "x2struct/x2struct.hpp"
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using namespace std;
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struct Test {
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int64_t uid;
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string name;
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XTOSTRUCT(A(uid, "id"), O(name)); // "uid"的别名是"id"
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};
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int main(int argc, char *argv[]) {
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Test t;
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string json="{\"id\":123, \"name\":\"Pony\"}";
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x2struct::X::loadjson(json, t, false);
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cout<<t.uid<<endl;
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return 0;
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}
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```
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继承
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----
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- 使用"I"来包含父类
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```C++
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#include <iostream>
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#include "x2struct/x2struct.hpp"
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using namespace std;
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struct P1 {
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string mail;
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XTOSTRUCT(O(mail));
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};
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struct P2 {
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int64_t version;
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XTOSTRUCT(O(version));
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};
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struct Test:public P1, public P2 {
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int64_t uid;
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string name;
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XTOSTRUCT(I(P1, P2), O(uid, name));
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};
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int main(int argc, char *argv[]) {
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Test t;
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string json="{\"mail\":\"pony@x2struct.com\", \"version\":2019, \"id\":123, \"name\":\"Pony\"}";
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x2struct::X::loadjson(json, t, false);
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cout<<t.mail<<endl;
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cout<<t.version<<endl;
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return 0;
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}
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```
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位域
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----
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- 使用"B"来包含位域变量
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``` C++
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#include <iostream>
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#include "x2struct/x2struct.hpp"
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using namespace std;
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struct Test {
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int16_t ver:8;
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int16_t len:8;
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string name;
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XTOSTRUCT(B(ver, len), O(name));
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};
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int main(int argc, char *argv[]) {
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Test t;
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string json="{\"ver\":4, \"len\":20, \"name\":\"IPv4\"}";
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x2struct::X::loadjson(json, t, false);
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cout<<t.ver<<endl;
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cout<<t.len<<endl;
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return 0;
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}
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```
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条件加载
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----
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- 用于从json对象数组里面加载满足条件的对象，最多加载一个
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- 用"C"包含需要条件加载的变量，放在XTOSTRUCT开头
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- 除了用"C"包含，条件加载的变量还需要继续用O/A/M中的一个包含
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```C++
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#include <iostream>
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#include "x2struct/x2struct.hpp"
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using namespace std;
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struct Task {
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int id;
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string name;
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XTOSTRUCT(O(id, name));
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};
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struct Test {
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int tid;
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Task task;
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XTOSTRUCT(C(task), O(tid, task)); // 在XTOSTRUCT里面，task既包含在"C"里面，也包含在"O"里面
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/*
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XTOSTRUCT_CONDITION 这个宏包含两个参数，一个类名，一个变量名
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XTOSTRUCT_CONDITION 定义了一个函数，函数有一个变量，名为"obj"指向的是变量对应的xdoc
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"task"在json里面是一个数组，这里只加载那个XTOSTRUCT_CONDITION返回true的那个，这里当tid等于id时返回true
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*/
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XTOSTRUCT_CONDITION(Test, task) {
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int id;
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// only load the one that Task.id is equal to Test.tid
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return obj.convert("id", id)&&id==this->tid;
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}
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};
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int main(int argc, char *argv[]) {
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string s = "{\"tid\":2019,\"task\":[{\"id\":2018,\"name\":\"hello\"},{\"id\":2019,\"name\":\"world\"}]}";
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Test t;
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x2struct::X::loadjson(s, t, false);
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cout<<t.task.name<<endl;
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}
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```
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char数组
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----
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修改[config.h](config.h)，使能XTOSTRUCT_SUPPORT_CHAR_ARRAY这个宏即可
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检查是否存在
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----
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- 用于json转结构体的时候，检查json里面的某个key是否存在
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- 用xhas函数检查
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```C++
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#include <iostream>
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#include "x2struct/x2struct.hpp"
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using namespace std;
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struct Test {
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int64_t id;
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string name;
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XTOSTRUCT(O(id, name));
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};
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int main(int argc, char *argv[]) {
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Test t;
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string json="{\"name\":\"Pony\"}";
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x2struct::X::loadjson(json, t, false, true); // 如果需要用这个功能，第四个参数需要是true
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cout<<t.xhas("id")<<endl; // 用xhas检查是否存在
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cout<<t.xhas("name")<<endl;
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return 0;
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}
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```
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局部类
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----
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- XTOSTRUCT会在结构体/类中添加模板函数，而局部类（定义在函数内的类）是不支持模板函数的
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- 用XTOSTRUCT_NT(types) 替代XTOSTRUCT, types支持Json/Xml/Bson/Config
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- 需要支持C++11
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- 目前局部类还不支持条件加载
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```C++
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// nt.cpp
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// g++ -o t nt.cpp -std=c++11
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#include <iostream>
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#include "x2struct/x2struct.hpp"
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using namespace std;
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int main(int argc, char *argv[]) {
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struct Test {
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int64_t id;
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string name;
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XTOSTRUCT_NT(Json)(O(id, name));
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};
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Test t;
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string json="{\"id\":123, \"name\":\"Pony\"}";
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x2struct::X::loadjson(json, t, false);
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cout<<t.name<<endl;
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return 0;
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}
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```
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自定义类型
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----
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- 自定义类型的本质是string类型
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- 需要实现这些函数:
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- std::string format() const; 用于将对象转为字符串
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- void parse(const std::string&); 用于将字符串转为对象
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- 最后用typedef XType<xxx> 完成自定义类型的定义
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- 以下代码是一个IPv4的例子
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```C++
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#include <iostream>
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#include "x2struct/x2struct.hpp"
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using namespace std;
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// 只是一个范例，没做错误处理
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struct _XIPv4 {
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uint32_t ip;
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// 实现format函数
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std::string format() const {
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char buf[64];
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int len = sprintf(buf, "%u.%u.%u.%u", ip>>24, 0xff&(ip>>16), 0xff&(ip>>8), 0xff&ip);
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return string(buf, len);
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}
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// 实现parse函数
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void parse(const std::string& d) {
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|||
|
|
uint32_t u[4];
|
|||
|
|
sscanf(d.c_str(), "%u.%u.%u.%u", &u[0], &u[1], &u[2], &u[3]);
|
|||
|
|
ip = (u[0]<<24)+(u[1]<<16)+(u[2]<<8)+u[3];
|
|||
|
|
}
|
|||
|
|
};
|
|||
|
|
|
|||
|
|
// typedef 定义
|
|||
|
|
typedef x2struct::XType<_XIPv4> XIPv4;
|
|||
|
|
|
|||
|
|
struct Test {
|
|||
|
|
XIPv4 ip;
|
|||
|
|
XIPv4 mask;
|
|||
|
|
XTOSTRUCT(O(ip, mask));
|
|||
|
|
};
|
|||
|
|
|
|||
|
|
int main(int argc, char *argv[]) {
|
|||
|
|
Test t;
|
|||
|
|
// 在json里面自定义类型是string
|
|||
|
|
string json="{\"ip\":\"192.168.1.2\", \"mask\":\"255.255.255.0\"}";
|
|||
|
|
|
|||
|
|
x2struct::X::loadjson(json, t, false);
|
|||
|
|
cout<<t.ip.ip<<','<<t.mask.ip<<endl;
|
|||
|
|
cout<<x2struct::X::tojson(t)<<endl;
|
|||
|
|
return 0;
|
|||
|
|
}
|
|||
|
|
```
|
|||
|
|
|
|||
|
|
第三方类和结构体
|
|||
|
|
----
|
|||
|
|
- 需要C++11支持
|
|||
|
|
- 用XTOSTRUCT_OUT而非XTOSTRUCT
|
|||
|
|
|
|||
|
|
```c++
|
|||
|
|
#include <sys/time.h>
|
|||
|
|
#include <iostream>
|
|||
|
|
#include "x2struct/x2struct.hpp"
|
|||
|
|
|
|||
|
|
using namespace std;
|
|||
|
|
|
|||
|
|
/*
|
|||
|
|
struct timeval {
|
|||
|
|
time_t tv_sec;
|
|||
|
|
suseconds_t tv_usec;
|
|||
|
|
};
|
|||
|
|
*/
|
|||
|
|
|
|||
|
|
// timeval is thirdparty struct
|
|||
|
|
XTOSTRUCT_OUT(timeval, O(tv_sec, tv_usec));
|
|||
|
|
|
|||
|
|
struct T {
|
|||
|
|
int a;
|
|||
|
|
string b;
|
|||
|
|
timeval t;
|
|||
|
|
XTOSTRUCT(O(a, b, t));
|
|||
|
|
};
|
|||
|
|
|
|||
|
|
|
|||
|
|
int main(int argc, char *argv[]) {
|
|||
|
|
T t;
|
|||
|
|
T r;
|
|||
|
|
t.a = 123;
|
|||
|
|
t.b = "x2struct";
|
|||
|
|
t.t.tv_sec = 888;
|
|||
|
|
t.t.tv_usec = 999;
|
|||
|
|
string s = x2struct::X::tojson(t);
|
|||
|
|
cout<<s<<endl;
|
|||
|
|
x2struct::X::loadjson(s, r, false);
|
|||
|
|
cout<<r.a<<','<<r.b<<','<<r.t.tv_sec<<','<<r.t.tv_usec<<endl;
|
|||
|
|
return 0;
|
|||
|
|
}
|
|||
|
|
```
|
|||
|
|
|
|||
|
|
格式化缩进
|
|||
|
|
----
|
|||
|
|
- tojson的最后两个参数控制
|
|||
|
|
|
|||
|
|
|
|||
|
|
xml bson libconfig
|
|||
|
|
----
|
|||
|
|
- 如果需要这些功能，需要修改[config.h](config.h)来开启
|
|||
|
|
- 不支持直接转换vector/map之类的，需要放结构体里面
|
|||
|
|
- 由于xml/libconfig不支持用纯数字作为key，所以如果需要用map<int, xxx>，那么key需要用x+数字的方式，比如x100
|
|||
|
|
- mongoxclient(https://github.com/xyz347/mongoxclient)是对mongo-cxx-driver的一个封装
|
|||
|
|
|
|||
|
|
|
|||
|
|
生成Golang结构体
|
|||
|
|
----
|
|||
|
|
- 用于将C++结构体转Golang结构体
|
|||
|
|
- 需要定义宏XTOSTRUCT_GOCODE
|
|||
|
|
```C++
|
|||
|
|
// go.cpp
|
|||
|
|
// g++ -o t go.cpp -DXTOSTRUCT_GOCODE
|
|||
|
|
#include <iostream>
|
|||
|
|
#include "x2struct/x2struct.hpp"
|
|||
|
|
|
|||
|
|
using namespace std;
|
|||
|
|
|
|||
|
|
struct Test {
|
|||
|
|
int64_t id;
|
|||
|
|
vector<string> names;
|
|||
|
|
XTOSTRUCT(O(id, names));
|
|||
|
|
};
|
|||
|
|
|
|||
|
|
int main(int argc, char *argv[]) {
|
|||
|
|
Test t;
|
|||
|
|
|
|||
|
|
cout<<x2struct::X::togocode(t, true, true, true)<<endl; // 最后三个参数用于控制(json/bson/xml) tag的生成
|
|||
|
|
return 0;
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
```
|
|||
|
|
|
|||
|
|
输出是:
|
|||
|
|
```go
|
|||
|
|
type Test struct {
|
|||
|
|
Id int64 `json:"id" bson:"id" xml:"id"`
|
|||
|
|
Names []string `json:"names" bson:"names" xml:"names"`
|
|||
|
|
}
|
|||
|
|
```
|
|||
|
|
|
|||
|
|
重要说明
|
|||
|
|
----
|
|||
|
|
- json的序列化反序列化用的是[rapidjson](https://github.com/Tencent/rapidjson)
|
|||
|
|
- xml的反序列化用的是[rapidxml](http://rapidxml.sourceforge.net)
|
|||
|
|
- bson的反序列化用的是[libbson](https://github.com/mongodb/libbson/tree/1.0.0)
|
|||
|
|
- libconfig的反序列化用的是[libconfig](https://github.com/hyperrealm/libconfig)
|
|||
|
|
- xml/bson的序列化是我自己写的，没有参考RFC，可能有和标准不一样的地方.
|
|||
|
|
- bson/libconfig的库是预编译的. 环境是: Ubuntu12.04 g++4.9.2. 其他环境如果想使用bson/libconfig可能需要自行编译这两个库
|
|||
|
|
- 有疑问可以加QQ群878041110
|