C++ 如何使用RapidJson 写入文件

#include <rapidjson/document.h>
#include <rapidjson/writer.h>
#include <rapidjson/stringbuffer.h>
#include <rapidjson/prettywriter.h> // for prettywriter
#include <rapidjson/filereadstream.h>
#include <rapidjson/filewritestream.h>
#include <cstdio>
using namespace rapidjson;
int main() {
    // 创建一个JSON对象
    Document d;
    d.SetObject();
    Document::AllocatorType& allocator = d.GetAllocator();
    d.AddMember("name", Value().SetString("John Doe", allocator), allocator);
    d.AddMember("age", 30, allocator);
    d.AddMember("is_student", false, allocator);
    // 写入文件
    FILE* fp = fopen("example.json", "wb"); // 非Windows平台可能需要使用 "w"
    char writeBuffer[65536];
    FileWriteStream os(fp, writeBuffer, sizeof(writeBuffer));
    PrettyWriter<FileWriteStream> writer(os);   // 注意，可以不使用PrettyWriter，不过，写出来的结构不好看，Pretty会将json写成树结构
    d.Accept(writer);
    fclose(fp);
    // 读取文件
    fp = fopen("example.json", "rb"); // 非Windows平台可能需要使用 "r"
    char readBuffer[65536];
    FileReadStream is(fp, readBuffer, sizeof(readBuffer));
    Document d2;
    d2.ParseStream(is);
    fclose(fp);
    // 输出读取的内容（简单示例）
    printf("Name: %s\n", d2["name"].GetString());
    printf("Age: %d\n", d2["age"].GetInt());
    printf("Is Student: %s\n", d2["is_student"].GetBool() ? "true" : "false");
    return 0;
}

#include <cstdio>
#include <rapidjson/document.h>
#include <rapidjson/writer.h>
#include <rapidjson/stringbuffer.h>
#include <rapidjson/prettywriter.h> // for PrettyWriter
#include <rapidjson/filewritestream.h>
using namespace rapidjson;
int main() {
    // 创建一个JSON文档，这将作为我们的根对象
    Document document;
    document.SetObject();
    Document::AllocatorType& allocator = document.GetAllocator();
    // 创建一个JSON数组
    Value array(kArrayType);
    // 创建第一个对象并添加到数组
    Value object1(kObjectType);
    object1.AddMember("id", 1, allocator);
    object1.AddMember("name", "John Doe", allocator);
    array.PushBack(object1, allocator);
    // 创建第二个对象并添加到数组
    Value object2(kObjectType);
    object2.AddMember("id", 2, allocator);
    object2.AddMember("name", "Jane Smith", allocator);
    array.PushBack(object2, allocator);
    // 创建第三个对象并添加到数组
    Value object3(kObjectType);
    object3.AddMember("id", 3, allocator);
    object3.AddMember("name", "Alice Johnson", allocator);
    array.PushBack(object3, allocator);
    // 将数组添加到根对象
    document.AddMember("users", array, allocator);
    // 将JSON写入文件
    FILE* fp = fopen("output.json", "wb"); // 非Windows平台可能需要使用 "w"
    char writeBuffer[65536];
    FileWriteStream os(fp, writeBuffer, sizeof(writeBuffer));
    PrettyWriter<FileWriteStream> writer(os);
    document.Accept(writer);
    fclose(fp);
    return 0;
}

#include <cstdio>
#include <rapidjson/document.h>
#include <rapidjson/writer.h>
#include <rapidjson/stringbuffer.h>
#include <rapidjson/prettywriter.h> // for PrettyWriter
#include <rapidjson/filewritestream.h>
using namespace rapidjson;
int main() {
    // 创建一个JSON文档，作为根对象
    Document document;
    document.SetObject();
    Document::AllocatorType& allocator = document.GetAllocator();
    // 创建一个JSON数组
    Value usersArray(kArrayType);
    // 使用for循环生成多个用户对象
    for (int i = 1; i <= 5; ++i) {
        Value userObject(kObjectType);
        // 为了示例简单，这里使用i作为id和name的一部分
        userObject.AddMember("id", i, allocator);
        // 创建一个具有动态字符串的Value
        std::string name = "User " + std::to_string(i);
        Value nameValue;
        nameValue.SetString(name.c_str(), static_cast<SizeType>(name.length()), allocator);
        userObject.AddMember("name", nameValue, allocator);
        // 将用户对象添加到数组中
        usersArray.PushBack(userObject, allocator);
    }
    // 将数组添加到根对象中
    document.AddMember("users", usersArray, allocator);
    // 写入文件
    FILE* fp = fopen("users_output.json", "wb"); // 非Windows平台可能需要使用 "w"
    char writeBuffer[65536];
    FileWriteStream os(fp, writeBuffer, sizeof(writeBuffer));
    PrettyWriter<FileWriteStream> writer(os);
    document.Accept(writer);
    fclose(fp);
    return 0;
}

#include <cstdio>
#include <string>
#include <rapidjson/document.h>
#include <rapidjson/prettywriter.h>
#include <rapidjson/filewritestream.h>
using namespace rapidjson;
int main() {
    // 创建根文档
    Document document;
    document.SetObject();
    Document::AllocatorType& allocator = document.GetAllocator();
    // 创建一个JSON数组用于存放部门信息
    Value departmentsArray(kArrayType);
    // 使用for循环添加部门和员工
    for (int depId = 1; depId <= 3; ++depId) {
        Value departmentObject(kObjectType);
        // 部门ID和名称
        departmentObject.AddMember("departmentId", depId, allocator);
        std::string depName = "Department " + std::to_string(depId);
        Value depNameValue;
        depNameValue.SetString(depName.c_str(), allocator);
        departmentObject.AddMember("name", depNameValue, allocator);
        // 为每个部门创建员工数组
        Value employeesArray(kArrayType);
        for (int empId = 1; empId <= 4; ++empId) {
            Value employeeObject(kObjectType);
            employeeObject.AddMember("employeeId", empId, allocator);
            std::string empName = "Employee " + std::to_string(empId) + " of Dep " + std::to_string(depId);
            Value empNameValue;
            empNameValue.SetString(empName.c_str(), allocator);
            employeeObject.AddMember("name", empNameValue, allocator);
            // 将员工对象添加到员工数组
            employeesArray.PushBack(employeeObject, allocator);
        }
        // 将员工数组添加到部门对象
        departmentObject.AddMember("employees", employeesArray, allocator);
        // 将部门对象添加到部门数组
        departmentsArray.PushBack(departmentObject, allocator);
    }
    // 将部门数组添加到根文档
    document.AddMember("departments", departmentsArray, allocator);
    // 写入文件
    FILE* fp = fopen("departments_output.json", "wb"); // 非Windows平台可能需要使用 "w"
    char writeBuffer[65536];
    FileWriteStream os(fp, writeBuffer, sizeof(writeBuffer));
    PrettyWriter<FileWriteStream> writer(os);
    document.Accept(writer);
    fclose(fp);
    return 0;
}