Android网络连接判断与检测

1.GET请求

 　　private fun httpGetDemo() {
         //1.请求参数
         val url = httpHost + "/api/test?arg1=xxx"

         //2.构造 OkHttpClient : 设置连接超时、读取超时、写出超时、cookie等
         var okhttp3 = OkHttpClient.Builder()
             .retryOnConnectionFailure(true)   //失败重连
             .connectTimeout(connectTimeout, TimeUnit.SECONDS)       //设置连接超时时间
             .readTimeout(readTimeout, TimeUnit.SECONDS)             //设置读取超时时间
             .writeTimeout(writeTimeout,TimeUnit.SECONDS)            //设置写出超时时间
             .cookieJar(cookieJar)                                   //设置cookie
             .build()

         //3.构造 Request ,设置请求方法，请求头参数
         var rb = Request.Builder()
             .url(url)                                   //指定请求地址
             .get()                                      //指定请求的方法

         //设置header的3种方法：
         //a, 添加 key - value
         rb.addHeader("header1","value1")    //添加自定义的header1
         rb.addHeader("header2","value2")    //添加自定义的header2

         //b, 按key修改value
         rb.header("Cookie","df")            //指定某个header的值

         //c,完全替换headers，注意它会把Request.Builder里设置的都删除，然后按自己添加的key-value重新设置当前builder的headers
         var hb = Headers.Builder()
         hb.add("header1","value1")
         hb.add("header2","value2")
         var headers = hb.build()
         rb.headers(headers)                             //指定headers

         var request = rb.build()

         //4.发起请求
         okhttp3.newCall(request).enqueue(object : Callback {
             override fun onFailure(call: Call, e: IOException) {

                 //5.处理请求失败
                 Log.e("DailyFrgmt","rollOverData onFailure error = " + e.message)
                 activity?.runOnUiThread {
                     Toast.makeText(getContext(),"查询翻身数据失败",Toast.LENGTH_SHORT).show()
                 }
             }
             override fun onResponse(call: Call, response: Response) {
                 //6.请求成功
                 var json = ""
                 //6.1 从response里可取得cookie
                 var url = request.url
                 var headers = response.headers
                 var cookies = Cookie.parseAll(url,headers)
                 for (cookie in cookies){
                     Log.e("Cookies ", "cookie : name = " + cookie.name + " value = " + cookie.value)
                 }
                 //6.2 得到2进制流，一般下载用，保存成文件。
                 var stream = response.body?.byteStream()
                 var br = BufferedInputStream(stream)
                 var len =
                 var buf = ByteArray( * )
                 do {
                     len = br.read(buf)
                     if (len > ){
                         json += String(buf,,len)
                     }
                 }while (len != -)
                 Log.e("DailyFrgmt","rollOverData onResponse = " + json)
                 if (LogUtil.TO_FILE){
                     try {
                         var js = context?.getExternalFilesDir("")?.absolutePath.toString() + "/rollover.json"
                         var fw = FileWriter(js)
                         fw.write(json)
                         fw.close()
                     }catch (e : java.lang.Exception){
                         e.printStackTrace()
                         Log.e("DailyFrgmt","exception = " + e.message)
                     }
                 }
                 //7.业务方法
             }
         })
 　　}

2.POST请求

      fun login( uname : String,pwd : String,failed : (reason : String?)  -> Unit,succeed : () -> Unit){
         val url = httpHost + "/api/login/"

         //1.构造post的json
         var jsObj = JSONObject()
         jsObj.put("userName",uname)
         jsObj.put("password", Encrypt.md5(pwd))
         var body = RequestBody.create("application/json; charset=utf-8".toMediaType(), jsObj.toString())

         //2.构造 OkHttpClient
         var okhttp3 = OkHttpClient.Builder()
             .retryOnConnectionFailure(true)   //失败重连
             .connectTimeout(connectTimeout, TimeUnit.SECONDS)       //设置连接超时时间
             .readTimeout(readTimeout, TimeUnit.SECONDS)             //设置读取超时时间
             .writeTimeout(writeTimeout,TimeUnit.SECONDS)
             .cookieJar(cookieJar)                                   //设置cookie
             .build()

         //3.构造post请求
         var rb = Request.Builder()
             .url(url)
             .post(body)

         //设置header的3种方法：
         //a, 添加 key - value
         rb.addHeader("header1","value1")    //添加自定义的header1
         rb.addHeader("header2","value2")    //添加自定义的header2

         //b, 按key修改value
         rb.header("Cookie","df")            //指定某个header的值

         //c,完全替换headers，注意它会把Request.Builder里设置的都删除，然后按自己添加的key-value重新设置当前builder的headers
         var hb = Headers.Builder()
         hb.add("header1","value1")
         hb.add("header2","value2")
         var headers = hb.build()
         rb.headers(headers)                             //指定headers

         var request = rb.build()

         //4.发送请求
         okhttp3.newCall(request).enqueue(object : Callback{
             override fun onFailure(call: Call, e: IOException) {
                 //5.处理失败
                 Log.e("Login","error = " + e.message)
                 failed("请求失败")
             }
             override fun onResponse(call: Call, response: Response) {
                 //6.请求成功
                 var json = ""
                 //6.1 从response里可取得cookie
                 var url = request.url
                 var headers = response.headers
                 var cookies = Cookie.parseAll(url,headers)
                 for (cookie in cookies){
                     Log.e("Cookies ", "cookie : name = " + cookie.name + " value = " + cookie.value)
                 }
                 //6.2 得到2进制流，一般下载用，保存成文件。
                 var stream = response.body?.byteStream()
                 var br = BufferedInputStream(stream)
                 var len =
                 var buf = ByteArray( * )
                 do {
                     len = br.read(buf)
                     if (len > ){
                         json += String(buf,,len)
                     }
                 }while (len != -)
                 //7.业务方法
                 onSomeFunction(json)
             }
         })
     }

3.关于Cookie

3.1 解析cookie

         //4.发送请求
         okhttp3.newCall(request).enqueue(object : Callback{
             override fun onFailure(call: Call, e: IOException) {
                 //5.处理失败
                 Log.e("Login","error = " + e.message)
                 failed("请求失败")
             }
             override fun onResponse(call: Call, response: Response) {
                 //6.请求成功
                 var json = ""
                 //6.1 从response里可取得cookie
                 var url = request.url
                 var headers = response.headers
                 var cookies = Cookie.parseAll(url,headers)
                 for (cookie in cookies){
                     Log.e("Cookies ", "cookie : name = " + cookie.name + " value = " + cookie.value)
                 }
                ...
             }
         })

3.2 使用CookieJar操作cookie(保存、上报、共享)

     var cm          = HashMap<String,List<Cookie> >()
     var cookieJar   = object : CookieJar{
         override fun loadForRequest(url: HttpUrl): List<Cookie> {
             var cookies = java.util.ArrayList<Cookie>()
             var cks = cm.get(url.host)
             if (cks != null){
                 cookies.addAll(cks)
             }
             for(cookie in cookies){
                 Log.i("cookieJar","loadForRequest cookie = ${cookie}")
             }
             return cookies
         }

         override fun saveFromResponse(url: HttpUrl, cookies: List<Cookie>) {
             cm.put(url.host,cookies)
         }
     }

     private fun testCookie() {
         //1.请求参数
         val url = httpHost + "/api/test?arg1=xxx"

         //2.构造 OkHttpClient : 设置连接超时、读取超时、写出超时、cookie等
         var okhttp3 = OkHttpClient.Builder()
             .retryOnConnectionFailure(true)   //失败重连
             .connectTimeout(connectTimeout, TimeUnit.SECONDS)       //设置连接超时时间
             .readTimeout(readTimeout, TimeUnit.SECONDS)             //设置读取超时时间
             .writeTimeout(writeTimeout,TimeUnit.SECONDS)            //设置写出超时时间
             .cookieJar(cookieJar)                                   //设置cookie处理对象
             .build()

             ...
     }

• loadForRequest        是请求时加载本地cookie 的调用
• saveFromResponse 是保存cookie时的调用
• 每个 OkHttpClient 可以指定一个 cookie处理对象，一般一个url可返回一个cookie,同一个主机所有子url可以使用相同的CookieJar对象。