Retrofit POST请求中400错误的根源与解决方案：对象序列化最佳实践

// 错误的Retrofit接口定义
public interface KidInterface {
  @Headers({"Content-Type:application/json; charset=utf-8"})
  @POST("kids")
  Call<Kid> createPost(@Body String kidJsonString); // 错误：期望接收JSON字符串
}

// 错误的使用方式
private void senddata(String nombre, String edad){
    // ... Retrofit初始化代码 ...

    KidInterface inter = retrofit.create(KidInterface.class);
    try {
        JSONObject obj = new JSONObject();
        obj.put("id", UUID.randomUUID().toString());
        obj.put("name", nombre);
        obj.put("edad", edad);
        // 错误：手动将JSONObject转换为字符串
        Call<Kid> call = inter.createPost(obj.toString()); 
        call.enqueue(this);
    } catch (JSONException e) {
        e.printStackTrace();
    }
}

import com.google.gson.annotations.SerializedName;

public class Kid {
    @SerializedName("id")
    public String id; // 使用public字段简化，或使用getter/setter
    @SerializedName("name")
    public String name;
    @SerializedName("edad")
    public String edad;

    // 构造函数用于初始化
    public Kid(String id, String name, String edad) {
        this.id = id;
        this.name = name;
        this.edad = edad;
    }

    // 也可以添加无参构造函数和setter/getter方法
    public Kid() {}
    // ... getter/setter ...
}

public interface KidInterface {
  @Headers({"Content-Type:application/json; charset=utf-8"})
  @POST("kids")
  Call<Kid> createPost(@Body Kid kidObject); // 正确：直接传递Kid对象
}

private void senddata(String nombre, String edad){
    // Retrofit客户端构建，确保添加了GsonConverterFactory
    OkHttpClient.Builder clientBuilder = new OkHttpClient.Builder();
    HttpLoggingInterceptor loggingInterceptor = new HttpLoggingInterceptor();
    loggingInterceptor.setLevel(HttpLoggingInterceptor.Level.BODY); // 方便调试
    clientBuilder.addInterceptor(loggingInterceptor);

    Retrofit retrofit = new Retrofit.Builder()
            .baseUrl("http://10.24.1.29/sicegipruebas4/api/")
            .client(clientBuilder.build())
            .addConverterFactory(GsonConverterFactory.create()) // 关键：启用Gson自动转换
            // .addConverterFactory(ScalarsConverterFactory.create()) // 如果不需要处理原始字符串响应，可以移除
            .build();

    KidInterface inter = retrofit.create(KidInterface.class);

    // 正确：创建Kid对象并填充数据
    Kid newKid = new Kid();
    newKid.id = UUID.randomUUID().toString();
    newKid.name = nombre;
    newKid.edad = edad;

    // 直接传递Kid对象
    Call<Kid> call = inter.createPost(newKid);
    call.enqueue(new Callback<Kid>() {
        @Override
        public void onResponse(Call<Kid> call, Response<Kid> response) {
            if (response.isSuccessful()) {
                // 请求成功，处理响应
                Kid createdKid = response.body();
                Log.d("Retrofit", "Kid created: " + createdKid.name);
            } else {
                // 请求失败，打印错误信息
                Log.e("Retrofit", "Error: " + response.code() + " - " + response.message());
                try {
                    Log.e("Retrofit", "Error Body: " + response.errorBody().string());
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }

        @Override
        public void onFailure(Call<Kid> call, Throwable t) {
            // 网络请求失败（如无网络连接）
            Log.e("Retrofit", "Network Error: " + t.getMessage());
        }
    });
}