Copyright (c) 2013-2018 brinkqiang ([email protected])
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dmjson mod by nlohmann/json
#include "dmjson.h"
#include "gtest.h"
#include <fstream>
#include <iostream>
#include <string>
using json = nlohmann::json;
class env_dmjson {
public:
void init() {}
void uninit() {}
};
class frame_dmjson : public testing::Test {
public:
virtual void SetUp() {
env.init();
}
virtual void TearDown() {
env.uninit();
}
protected:
env_dmjson env;
};
TEST_F(frame_dmjson, dmjson) {
// 1. 创建 JSON 对象
json j;
// 2. 基本数据类型写入
j["name"] = "张三";
j["age"] = 25;
j["height"] = 175.5;
j["is_student"] = true;
j["address"] = nullptr;
// 3. 数组操作
j["hobbies"] = json::array({"读书", "游泳", "编程"});
j["scores"].push_back(95);
j["scores"].push_back(87);
j["scores"].push_back(92);
// 4. 嵌套对象
j["contact"]["phone"] = "13800138000";
j["contact"]["email"] = "[email protected]";
// 5. 使用初始化列表创建复杂 JSON
json j2 = {
{"students", {
{
{"id", 1001},
{"name", "李四"},
{"grades", {
{"math", 95},
{"english", 88},
{"chinese", 92}
}}
},
{
{"id", 1002},
{"name", "王五"},
{"grades", {
{"math", 87},
{"english", 94},
{"chinese", 89}
}}
}
}},
{"class_name", "高三一班"},
{"teacher", "赵老师"}
};
// 6. JSON 序列化 - 转换为字符串
std::string json_str = j.dump();
std::string json_str_pretty = j.dump(4); // 格式化输出，缩进4个空格
std::cout << "压缩格式: " << json_str << std::endl;
std::cout << "格式化输出:\n" << json_str_pretty << std::endl;
// 7. JSON 反序列化 - 从字符串解析
std::string input_json = R"({
"product": "笔记本电脑",
"price": 5999.99,
"specs": {
"cpu": "Intel i7",
"memory": "16GB",
"storage": "512GB SSD"
},
"available": true,
"tags": ["办公", "游戏", "学习"]
})";
try {
json parsed_json = json::parse(input_json);
// 8. 安全访问 JSON 数据
if (parsed_json.contains("product")) {
std::string product = parsed_json["product"];
EXPECT_EQ(product, "笔记本电脑");
}
if (parsed_json.contains("price") && parsed_json["price"].is_number()) {
double price = parsed_json["price"];
EXPECT_DOUBLE_EQ(price, 5999.99);
}
// 9. 访问嵌套对象
if (parsed_json.contains("specs") && parsed_json["specs"].is_object()) {
std::string cpu = parsed_json["specs"]["cpu"];
EXPECT_EQ(cpu, "Intel i7");
}
// 10. 遍历数组
if (parsed_json.contains("tags") && parsed_json["tags"].is_array()) {
for (const auto& tag : parsed_json["tags"]) {
std::cout << "标签: " << tag << std::endl;
}
EXPECT_EQ(parsed_json["tags"].size(), 3);
}
// 11. 使用 at() 方法安全访问（会抛出异常）
try {
std::string cpu = parsed_json.at("specs").at("cpu");
EXPECT_EQ(cpu, "Intel i7");
} catch (const json::exception& e) {
std::cerr << "JSON 访问错误: " << e.what() << std::endl;
}
// 12. 使用 value() 方法提供默认值
std::string brand = parsed_json.value("brand", "未知品牌");
int warranty = parsed_json.value("warranty", 12); // 默认12个月
EXPECT_EQ(brand, "未知品牌");
EXPECT_EQ(warranty, 12);
} catch (const json::parse_error& e) {
std::cerr << "JSON 解析错误: " << e.what() << std::endl;
FAIL() << "JSON 解析失败";
}
// 13. 文件读写操作
const std::string filename = "test_data.json";
// 写入文件
try {
std::ofstream file(filename);
if (file.is_open()) {
file << j2.dump(4);
file.close();
}
} catch (const std::exception& e) {
std::cerr << "文件写入错误: " << e.what() << std::endl;
}
// 从文件读取
try {
std::ifstream file(filename);
if (file.is_open()) {
json file_json;
file >> file_json;
file.close();
// 验证读取的数据
EXPECT_TRUE(file_json.contains("class_name"));
EXPECT_EQ(file_json["class_name"], "高三一班");
// 清理测试文件
std::remove(filename.c_str());
}
} catch (const json::exception& e) {
std::cerr << "文件读取错误: " << e.what() << std::endl;
}
// 14. 类型检查
json type_test = {
{"string_val", "hello"},
{"number_val", 42},
{"float_val", 3.14},
{"bool_val", true},
{"null_val", nullptr},
{"array_val", {1, 2, 3}},
{"object_val", {{"key", "value"}}}
};
EXPECT_TRUE(type_test["string_val"].is_string());
EXPECT_TRUE(type_test["number_val"].is_number_integer());
EXPECT_TRUE(type_test["float_val"].is_number_float());
EXPECT_TRUE(type_test["bool_val"].is_boolean());
EXPECT_TRUE(type_test["null_val"].is_null());
EXPECT_TRUE(type_test["array_val"].is_array());
EXPECT_TRUE(type_test["object_val"].is_object());
// 15. JSON Patch 操作示例
json original = {{"name", "原始值"}, {"count", 10}};
json patch = json::array({
{{"op", "replace"}, {"path", "/name"}, {"value", "新值"}},
{{"op", "add"}, {"path", "/description"}, {"value", "添加的描述"}}
});
// 注意: JSON Patch 需要额外的库支持，这里仅作示例
// 16. 遍历 JSON 对象
json obj = {{"a", 1}, {"b", 2}, {"c", 3}};
for (auto& [key, value] : obj.items()) {
std::cout << "键: " << key << ", 值: " << value << std::endl;
}
// 17. JSON 合并
json base = {{"name", "base"}, {"version", 1}};
json update = {{"version", 2}, {"author", "更新者"}};
base.update(update);
EXPECT_EQ(base["version"], 2);
EXPECT_EQ(base["author"], "更新者");
EXPECT_EQ(base["name"], "base");
std::cout << "所有 JSON 操作测试完成!" << std::endl;
}