Android Kotlin 连接 http

　　由于近期网上搜索了很多Android连接到http的方法， 可是2013年以前的方法现在都不能用了，要么报错，要么被遗弃，岁月留下来的东西只能自己整理了。

　　其实很简单，就一个HttpUtil通用类。可以实现Get和Post方法，其他东西，里面可以随便改改，基本就这样吧。

　　参数的话，我用了一个 strUrlPath网址、params键值对、encode编码（如utf-8）。

　　

package Util

import android.os.Handler
import android.os.Message
import android.view.View
import android.widget.Button
import java.io.BufferedReader
import java.io.ByteArrayOutputStream
import java.io.IOException
import java.io.InputStream
import java.io.InputStreamReader
import java.io.OutputStream
import java.net.HttpURLConnection
import java.net.MalformedURLException
import java.net.URL
import java.net.URLEncoder

/**
 * Created by Jason_Jan on 2017/7/5.
 */

object HttpUtil {

    private var handler: Handler? = null
    private var my_result: String? = null

    fun httpGet(strUrlPath: String, params: Map<String, String>, encode: String): String {
        var strUrlPath = strUrlPath
        /* byte[] data = getRequestData(params, encode).toString().getBytes();//获得请求体*/
        /* String target="http://emb.mobi/register";*/
        var result: String? = null
        val append_url = getRequestData(params, encode).toString()
        strUrlPath = strUrlPath + "?" + append_url
        try {
            val url = URL(strUrlPath)
            val urlConn = url.openConnection() as HttpURLConnection
            urlConn.connectTimeout = 5000//超时时间
            urlConn.setRequestProperty("Content-Type", "application/x-www-form-urlencoded")//设置头部信息，其实没什么用

            //主角开始登场，不注意就是几个小时的调试，输入流
            val `in` = InputStreamReader(urlConn.inputStream)

            val buffer = BufferedReader(`in`)
            var inputLine: String? = null
            //循环逐行读取输入流中的内容

            result = ""//每次清空数据

            while (buffer.readLine().apply { inputLine = this } != null) {
                result += inputLine!! + "\n"
            }

            `in`.close()
            urlConn.disconnect()

        } catch (e: MalformedURLException) {
            e.printStackTrace()
        } catch (ioe: IOException) {
            ioe.printStackTrace()
            return "err:" + ioe.message.toString()
        }

        return result!!

    }

    private fun getRequestData(params: Map<String, String>, encode: String): StringBuffer {
        val stringBuffer = StringBuffer()        //存储封装好的请求体信息
        try {
            for ((key, value) in params) {
                stringBuffer.append(key)
                        .append("=")
                        .append(URLEncoder.encode(value, encode))
                        .append("&")
            }
            stringBuffer.deleteCharAt(stringBuffer.length - 1)    //删除最后的一个"&"
        } catch (e: Exception) {
            e.printStackTrace()
        }

        return stringBuffer
    }

    fun httpPost(strUrlPath: String, params: Map<String, String>, encode: String): String {
        val data = getRequestData(params, encode).toString().toByteArray()
        try {
            val url = URL(strUrlPath)

            val http = url.openConnection() as HttpURLConnection
            http.connectTimeout = 5000
            http.doInput = true
            http.doOutput = true
            http.requestMethod = "POST"
            http.useCaches = false//使用post方式不能用缓存
            //设置请求体的类型是文本类型
            http.setRequestProperty("Content-Type", "application/x-www-form-urlencoded")
            //设置请求体的长度
            http.setRequestProperty("Content-Length", data.size.toString())
            //获得输出流，向服务器写入数据
            val out = http.outputStream
            out.write(data)

            val response = http.responseCode
            if (response == HttpURLConnection.HTTP_OK) {
                val inputStream = http.inputStream
                return dealResponseResult(inputStream)
            }

        } catch (ioe: IOException) {
            ioe.printStackTrace()
            return "err:" + ioe.message.toString()
        }

        return "-1"
    }

    fun dealResponseResult(inputStream: InputStream): String {
        var resultData: String? = null      //存储处理结果
        val byteArrayOutputStream = ByteArrayOutputStream()
        val data = ByteArray(1024)
        var len = 0
        try {
            while (inputStream.read(data).apply { len = this } != -1) {
                byteArrayOutputStream.write(data, 0, len)
            }
        } catch (e: IOException) {
            e.printStackTrace()
        }

        resultData = String(byteArrayOutputStream.toByteArray())
        return resultData
    }
}

　　

　　

　　使用方式很简单--HttpUtil.方法名（参数），返回一个string,之后用Json解析工具来解析。

　　其次重中之重，安卓网络连接有点坑。下面从两个方面谈谈。

　　1.getoutputstream这里，一直报错。解决方案：build.gradle

compile 'com.squareup.retrofit:retrofit:1.8.0'
compile 'com.squareup.okhttp:okhttp:2.1.0'
compile 'com.squareup.okhttp:okhttp-urlconnection:2.1.0'

　　2.其次，在AndroidManifest.xml中

<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.INTERNET" />