简单说一下学习okhttp的理由

1. google在Android 6.0中删除了HttpClient的Api,采用的是则是okhttp
2. 高效的使用HTTP,使应用运行更快更省流量
3. 响应缓存数据避免重复网络请求
4. 无缝的支持GZIP来减少数据流量
5. 使用非常简单，请求和响应的Api具有流畅的建造和不变性，同时支持同步异步调用回调函数
6. 如果网络出现问题，它会从常见的连接问题中恢复
7. 如果服务器配置有多个IP地址，当第一个IP连接失败，它会尝试连接下一个IP

以上是okhttp官网http://square.github.io/okhttp/以及结合网上的一些理解整理

配置环境

在builde.gradle里面添加上

compile ‘com.squareup.okhttp3:okhttp:3.4.1‘

在AndroidManifest.xml添加所需权限

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

基本使用

import com.google.gson.Gson;
import com.google.gson.JsonParseException;
import com.google.gson.JsonSyntaxException;

import java.io.IOException;
import java.util.Map;
import java.util.concurrent.TimeUnit;

import okhttp3.Call;
import okhttp3.Callback;
import okhttp3.FormBody;
import okhttp3.OkHttpClient;
import okhttp3.Request;
import okhttp3.RequestBody;
import okhttp3.Response;

/**
 * Created by 95224 on 2016.
 */
public class OkHttpHelper {
    private static OkHttpClient okHttpClient;
    private Gson mGson;
    private OkHttpHelper() {
            okHttpClient =new OkHttpHelper.Builder().connectTimeout(10, TimeUnit.SECONDS).writeTimeout(10,TimeUnit.SECONDS)
                    .readTimeout(20,TimeUnit.SECONDS)
                    .build();
        mGson = new Gson();
    }

    public static OkHttpHelper getInstance() {

        return new OkHttpHelper();
    }

    public void doRequest(final Request request, final BaseCallback callback) {
        callback.onRequestBrfore(request);
        okHttpClient.newCall(request).enqueue(new Callback() {
            @Override
            public void onFailure(Call call, IOException e) {
                callback.onFailure(request,e);
            }

            @Override
            public void onResponse(Call call, Response response) throws IOException {
                if (response.isSuccessful()) {
                    String resultStr=response.body().string();
                    if (callback.mType == String.class) {
                        callback.onSuccess(response,resultStr);
                    }else{
                        try {
                            Object object = mGson.fromJson(resultStr, callback.mType);
                            callback.onSuccess(response, object);
                        }catch (JsonSyntaxException e){
                            callback.onError(response,response.code(),e);
                        }catch (JsonParseException e){
                            callback.onError(response,response.code(),e);
                        }
                    }
                }else{
                    callback.onError(response,response.code(),null);
                }
            }
        });
    }

    public void get(String url,BaseCallback callback) {
        Request request = buildRequest(url, null, HttpMethodType.GET);
        doRequest(request,callback);
    }

    public void post(String url, Map<String, Object> params,BaseCallback callback) {
        Request request =buildRequest(url,params ,HttpMethodType.POST);
        doRequest(request,callback);
    }

    private Request buildRequest(String url, Map<String, Object> params, HttpMethodType methodType) {
        Request.Builder builder = new Request.Builder();
        builder.url(url);
        if (methodType == HttpMethodType.GET) {
            builder.get();
        } else if (methodType == HttpMethodType.POST) {
            RequestBody body = buildFormatData(params);
            builder.post(body);
        }
        return builder.build();
    }

    private RequestBody buildFormatData(Map<String, Object> params) {
        FormBody.Builder builder=new FormBody.Builder();
        if (params !=null) {
           for (Map.Entry<String,Object> entry : params.entrySet()){
               builder.add(entry.getKey(),entry.getValue().toString());
           }
        }
        return builder.build();
    }

    enum HttpMethodType{
        GET,POST
    }

OKHttp的使用