通过最近几天的研究，我发现cppcms的API有更高级更丰富的功能，比如URL的映射，JSON value与常用数据类型的转换。其配置文件也有很丰富的选项，比如多线程和多进程模式，网络参数等。

代码示例如下：

#include <cppcms/application.h>
#include <cppcms/applications_pool.h>
#include <cppcms/service.h>
#include <cppcms/http_response.h>
#include <cppcms/rpc_json.h>
#include <cppcms/json.h>
#include <cppcms/mount_point.h>
#include <map>
#include <string>

#include <exception>
#include <iostream>

using namespace std;
using cppcms::rpc::json_rpc_server;
using cppcms::rpc::json_method;

class calc_service : public json_rpc_server {
public:
    calc_service(cppcms::service &srv) : json_rpc_server(srv) {
        bind("sum",
            json_method(&calc_service::sum,this),method_role);
        bind("div",
            json_method(&calc_service::div,this),method_role);
    }
    void sum(int x,int y) {
        cppcms::json::value v;
        v["x"]=x;
        v["y"]=y;
        v["result"]=x+y;
        return_result(v);
    }
    void div(int x,int y) {
        if(y == 0) {
            return_error("Division by zero.");
        } else {
            return_result(x/y);
        }
    }
};

class hello_service : public json_rpc_server {
public:
    hello_service(cppcms::service &srv) : json_rpc_server(srv) {
        bind("hello",
            json_method(&hello_service::hello,this),method_role);
        bind("hello_all",
            json_method(&hello_service::hello_all,this),method_role);
        bind("hello_x",
            json_method(&hello_service::hello_x,this),method_role);
    }
    void hello(string name) {
        string say="Hello, " + name + ".";
        return_result(say);
    }
    void hello_all(vector<string> names) {
        string say="Hello, ";
        for(unsigned i=0;i<names.size();i++) {
            say += names[i] + " ";
        }
        return_result(say);
    }
    void hello_x(cppcms::json::value val) {
        return_result(val);
    }
};

int main(int argc,char **argv) {
    try {
        cppcms::service srv(argc,argv);

        srv.applications_pool().mount(
            cppcms::applications_factory<calc_service>(),
            cppcms::mount_point("/calc")
        );

        srv.applications_pool().mount(
            cppcms::applications_factory<hello_service>(),
            cppcms::mount_point("/hello")
        );
        srv.run();
    } catch (exception const &e) {
        cerr << e.what() << endl;
    }
    return 0;
}

配置文件示例：

{
    "service" : {
        "api" : "http",
        "ip" : "0.0.0.0",
        "port" : 8080,
        "worker_threads" : 50,
        "worker_processes" : 4,
        "backlog" : 1024,
        "application_pool_size" : 128,
        
    },
    "http" : {
        "script_names" : [ "/calc","/hello" ]
    }
}