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官网：http://rapidjson.org/zh-cn/
开发环境：VS code 2019

一、环境配置

1、下载rapidjson

下载网址：https://github.com/Tencent/rapidjson/
下载完成之后，打开目录，可以看到以下文件，其中include是主要文件，也是最重要的文件

可以将文件移动到工程项目里面

2、添加库的链接

打开调试属性

选择VC++目录->包含目录

将上面的include目录包含进来，即可使用了，$(SolutionDir)表示当前的工程目录
$(SolutionDir)thrid\rapidjson\include

二、rapidjson例程

读取JSON文件，获取对应元素

#include <iostream>
#include <string>
#include "rapidjson/document.h"
#include "rapidjson/writer.h"
#include "rapidjson/stringbuffer.h"

using namespace rapidjson;
using namespace std;

string readfile(const char* filename) {
    FILE* fp = fopen(filename, "rb");
    if (!fp) {
        printf("open failed! file: %s", filename);
        return "";
    }

    /*
     
    FILE* fp = fopen(filename, "rb");
    if (!fp) {
        printf("open failed! file: %s", filename);
        return "";
    }
    char* buf = new char[1024 * 16];
    int n = fread(buf, 1, 1024 * 16, fp);
    fclose(fp);

    string result;
    if (n >= 0) {
        result.append(buf, 0, n);
    }
    delete[]buf;
    */

    char buf[1024 * 16]; //新建缓存区
    string result;

    /*循环读取文件，直到文件读取完成*/
    while (int n = fgets(buf, 1024 * 16, fp) != NULL)
    {
        //int len = strlen(buf);
        //buf1[len - 1] = '\0';  /*去掉换行符*/
        //printf("%s %d \n", buf, len - 1);
        result.append(buf);
        //cout << buf << endl;
    }
    fclose(fp);
    //cout << result << endl;

    return result;
}
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   
int parseJSON(const char* jsonstr) {
    Document d;
    if (d.Parse(jsonstr).HasParseError()) {
        printf("parse error!\n");
        return -1;
    }
    if (!d.IsObject()) {
        printf("should be an object!\n");
        return -1;
    }
    if (d.HasMember("errorCode")) {
        Value& m = d["errorCode"];
        int v = m.GetInt();
        printf("errorCode: %d\n", v);
    }
    printf("show numbers: \n");
    if (d.HasMember("numbers")) {
        Value& m = d["numbers"];
        if (m.IsArray()) {
            for (int i = 0; i < m.Size(); i++) {
                Value& e = m[i];
                int n = e.GetInt();
                printf("%d,", n);
            }
        }
    }
    return 0;
}

int parseJSON2(const char* jsonstr) {
    Document d;
    if (d.Parse(jsonstr).HasParseError()) {
        throw string("parse error!\n");
    }
    if (!d.IsObject()) {
        throw string("should be an object!\n");
    }

    /*判断是否存在Joints*/
    if (!d.HasMember("Joints")) {
        throw string("'Joints' no found!");
    }

    


    /*查看Joints的个数和数据类型*/
    Value& j = d["Joints"];
    cout << typeid(j).name() << endl;
    cout << j.Size() << endl;


    /*查看Joints下第一个Joints的ID*/
    Value& m = d["Joints"][0];
    m.HasMember("ID");

    if (m.IsObject()){
        cout << "ID" << endl;
        if (m["ID"].IsInt()) {
            int ID = m["ID"].GetInt();
            cout << ID << endl;
        }
       

    }

    //string v = m.GetString();
    //printf("errorCode: %d\n", v);
    //printf("show numbers:\n");
    /*
    if (d.HasMember("numbers")) {
        Value& m = d["numbers"];
        if (m.IsArray()) {
            for (int i = 0; i < m.Size(); i++) {
                Value& e = m[i];
                int n = e.GetInt();
                printf("%d", n);
            }
        }
    }
    */
    return 0;
}

/*
 //path="/Users/macname/Desktop/example.json"

 {
 "errorCode":0,
 "reason":"OK",
 "result":{"userId":10086,"name":"中国移动"},
 "numbers":[110,120,119,911]
 }

 */
int main() {

    string jsonstr = readfile("C:/OpenGL/JSONloader/JSONloader/JSONloader/venue2654_v4.json");
    //string jsonstr = readfile("C:/OpenGL/JSONloader/JSONloader/JSONloader/test.txt");
    //parseJSON(jsonstr.c_str());

    try {
        parseJSON2(jsonstr.c_str());
    }
    catch (string e) {
        printf("error: %s \n", e.c_str());
    }
    getchar();
    
    return 0;
}

简洁版

#include <iostream>
#include <string>
#include "rapidjson/document.h"
#include "rapidjson/writer.h"
#include "rapidjson/stringbuffer.h"

using namespace rapidjson;
using namespace std;

string readfile(const char* filename) {
    FILE* fp = fopen(filename, "rb");
    if (!fp) {
        printf("open failed! file: %s", filename);
        return "";
    }
    char buf[1024 * 16]; //新建缓存区
    string result;
   /*循环读取文件，直到文件读取完成*/
    while (int n = fgets(buf, 1024 * 16, fp) != NULL)
    {
            result.append(buf);
        //cout << buf << endl;
    }
    fclose(fp);
    return result;
}

int parseJSON2(const char* jsonstr) {
    Document d;
    if (d.Parse(jsonstr).HasParseError()) {
        throw string("parse error!\n");
    }
    if (!d.IsObject()) {
        throw string("should be an object!\n");
    }

    /*判断是否存在Joints*/
    if (!d.HasMember("Joints")) {
        throw string("'Joints' no found!");
    }

    /*查看Joints的个数和数据类型*/
    Value& j = d["Joints"];
    cout << typeid(j).name() << endl;
    cout << j.Size() << endl;

    /*查看Joints下第一个Joints的ID*/
    Value& m = d["Joints"][0];
    m.HasMember("ID");

    if (m.IsObject()){
        cout << "ID" << endl;
        if (m["ID"].IsInt()) {
            int ID = m["ID"].GetInt();
            cout << ID << endl;
        }
    }
        return 0;
}

int main() {

    string jsonstr = readfile("C:/OpenGL/JSONloader/JSONloader/JSONloader/venue2654_v4.json");
        try {
        parseJSON2(jsonstr.c_str());
    }
    catch (string e) {
        printf("error: %s \n", e.c_str());
    }
        return 0;
}