네트워크 I/O (기본)

Kotlin code

import java.net.HttpURLConnection
import java.net.URL

fun httpGet(urlStr: String): Result<String> = runCatching {
    val url = URL(urlStr)
    val conn = url.openConnection() as HttpURLConnection
    conn.apply {
        requestMethod = "GET"
        connectTimeout = 5000
        readTimeout = 5000
        setRequestProperty("Accept", "application/json")
    }

    try {
        if (conn.responseCode == 200) {
            conn.inputStream.bufferedReader().use { it.readText() }
        } else {
            throw RuntimeException("HTTP ${conn.responseCode}: ${conn.responseMessage}")
        }
    } finally {
        conn.disconnect()
    }
}

fun httpPost(urlStr: String, body: String): Result<String> = runCatching {
    val conn = URL(urlStr).openConnection() as HttpURLConnection
    conn.apply {
        requestMethod = "POST"
        doOutput = true
        setRequestProperty("Content-Type", "application/json")
    }
    conn.outputStream.use { it.write(body.toByteArray()) }
    conn.inputStream.bufferedReader().use { it.readText() }
}

fun main() {
    httpGet("https://httpbin.org/get").fold(
        onSuccess = { println("응답: ${it.take(200)}...") },
        onFailure = { println("오류: ${it.message}") }
    )
}