記錄一下kotlin使用HttpURLConnection封裝http請求

一般都是用HttpClient去發請求的，但是項目中用HttpURLConnection就行了，所以以下是用HttpURLConnection封裝的。
封裝http：

import org.slf4j.LoggerFactory
import org.springframework.stereotype.Service
import java.io.BufferedReader
import java.io.InputStreamReader
import java.io.OutputStreamWriter
import java.io.PrintWriter
import java.net.HttpURLConnection
import java.net.URL
import java.net.URLEncoder

@Service
class HttpService {
    private val log = LoggerFactory.getLogger(HttpService::class.java)

    @Throws(Exception::class)
    fun sendGetRequest(url: String, charset: String = "utf-8"): String {
        log.info("get url:>>>$url")
        var resultBuffer = StringBuffer()
        var httpURLConnection = URL(url).openConnection() as HttpURLConnection
        httpURLConnection.setRequestProperty("Accept-Charset", charset)
        httpURLConnection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded")
        if (httpURLConnection.responseCode >= 300) throw Exception("HTTP Request is not success, Response code is ${httpURLConnection.responseCode}")
        val inputStream = httpURLConnection.inputStream
        val inputStreamReader = InputStreamReader(inputStream, charset)
        val reader = BufferedReader(inputStreamReader)
        reader.use { r ->
            var temp = r.readLine()
            if (temp != null) resultBuffer.append(temp)
        }
        reader.close()
        inputStreamReader.close()
        inputStream.close()
        return resultBuffer.toString()
    }

    @Throws(Exception::class)
    fun sendPostRequest(reqBody: String, url: String, charset: String = "utf-8"): String {
        log.info("post params:>>$reqBody;url:>>$url")
        val bufferResult = StringBuffer()
        val conn = URL(url).openConnection()
        conn.setRequestProperty("accept", "*/*")
        conn.setRequestProperty("connection", "Keep-Alive")
        conn.setRequestProperty("user-agent",
                "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)")
        // 發送POST請求必須設置如下兩行
        conn.setDoOutput(true)
        conn.setDoInput(true)

        val out = PrintWriter(OutputStreamWriter(conn.outputStream, charset))
        //發送請求
        out.print(reqBody)
        //flush 輸出流緩衝
        out.flush()
        val inStream = BufferedReader(InputStreamReader(conn.inputStream, charset))
        inStream.use { r ->
            val temp = r.readLine()
            if (temp != null) bufferResult.append(temp)
        }
        out.close()
        inStream.close()

        return bufferResult.toString()
    }

    fun getParamStr (params: Map<String, String>): String {
        val str = StringBuffer()
        var temp = ""
        params.keys.map {k ->
             temp = k + "=" + URLEncoder.encode(params.get(k), "utf-8") + "&"
            str.append(temp)
        }
        return str.toString().substring(0, str.toString().count() - 1)
    }

}

調用方式：

val params = HashMap<String, String>()
...
httpService.sendPostRequest(httpService.getParamStr(params), "http://ip:port/serviceName")