OkHttp学习笔记

1、为什么使用Okhttp？

以前google推荐使用Volley框架，Volley封装了HttpClient，但是Android6.0之后废弃HTTPClient相关属性导致Volley不能使用（可以将HTTPClient做Library导入解决此问题）。具体Volley代码展示：

OkHttp可以是可以解决此问题的一个很好的框架。

2、使用代码

package com.example.okhttpdemo;

import android.annotation.SuppressLint;
import android.os.Bundle;
import android.os.Environment;
import android.os.Handler;
import android.os.Message;
import android.support.annotation.Nullable;
import android.support.v7.app.AppCompatActivity;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Toast;

import com.example.okhttpdemo.R;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;

import okhttp3.Call;
import okhttp3.Callback;
import okhttp3.FormBody;
import okhttp3.MediaType;
import okhttp3.MultipartBody;
import okhttp3.OkHttpClient;
import okhttp3.Request;
import okhttp3.RequestBody;
import okhttp3.Response;
import okio.BufferedSink;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

    }


    public void btn(View v) throws IOException {
        switch (v.getId()) {
            case R.id.btnGet:
                doGet();
                break;
            case R.id.btnPost:
                doPost();
                break;
            case R.id.btnPostString:
                doPostString();
                break;
            case R.id.btnDown:
                doDownLoad();
                break;
        }

    }



    @SuppressLint("HandlerLeak")
    Handler handler=new Handler(){
        @Override
        public void handleMessage(Message msg) {
            super.handleMessage(msg);
                Toast.makeText(MainActivity.this, (String)msg.obj, Toast.LENGTH_SHORT).show();
        }
    };

    OkHttpClient okHttpClient = new OkHttpClient();
    private void doGet() throws IOException {
        //1、拿到OkHttpClient对象
//        OkHttpClient okHttpClient = new OkHttpClient();
        //2、构造Request
        Request.Builder builder = new Request.Builder();
        Request build = builder.get().url("https://www.baidu.com/").build();
        exeRequest(build);


    }

    private void exeRequest(Request build) {
        //3、将Request封装成Call
        Call call = okHttpClient.newCall(build);

        //4、执行Call
//        Response response = call.execute();//同步
        call.enqueue(new Callback() {//异步
            @Override
            public void onFailure(Call call, IOException e) {

            }

            @Override
            public void onResponse(Call call, final Response response) throws IOException {
                Log.i("aa", Thread.currentThread().toString());
                Message message=Message.obtain();
                message.obj=response.body().toString();
                handler.sendMessage(message);
            }
        });
    }

    /**
     * 正常post请求
     */
    private void doPost() {
        Request.Builder builder=new Request.Builder();

        FormBody formBody=new FormBody.Builder().add("key1","value1").build();
        Request build = builder.url("").post(formBody).build();
        exeRequest(build);
    }

    /**
     * post一个字符串
     */
    private void doPostString() {

        RequestBody requestBody=RequestBody.create(MediaType.parse("text/plain,chaset=utf-8"),"aaaa");

        Request.Builder builder=new Request.Builder();
        Request build = builder.url("").post(requestBody).build();
        exeRequest(build);
    }
    /**
     * post一个File
     */
    private void doPostFile() {

        File file=null;
        RequestBody requestBody=RequestBody.create(MediaType.parse("application/octet-stream"),file);

        Request.Builder builder=new Request.Builder();
        Request build = builder.url("").post(requestBody).build();
        exeRequest(build);
    }



    /**
     * post一个File+其他参数
     */
    private void doPostFileAndOther() {



        File file=null;
        RequestBody requestBody=RequestBody.create(MediaType.parse("application/octet-stream"),file);


        MultipartBody.Builder multipartBody=new MultipartBody.Builder();
        MultipartBody build1 = multipartBody.setType(MultipartBody.FORM).addFormDataPart("", "").addPart(requestBody).build();


        Request.Builder builder=new Request.Builder();
        Request build = builder.url("").post(build1).build();
        exeRequest(build);
    }



    /**
     * 下载文件
     */
    private void doDownLoad() {

        Request.Builder builder = new Request.Builder();
        Request build = builder.get().url("https://wx4.sinaimg.cn/mw690/8f4241dbly1fs1i0y9613j23402c0qkq.jpg").build();


        //3、将Request封装成Call
        Call call = okHttpClient.newCall(build);

        //4、执行Call
//        Response response = call.execute();//同步
        call.enqueue(new Callback() {//异步
            @Override
            public void onFailure(Call call, IOException e) {

            }

            @Override
            public void onResponse(Call call, final Response response) throws IOException {

                File file=new File(Environment.getExternalStorageDirectory()+"/zz.jpg");

                InputStream inputStream = response.body().byteStream();

                int len=0;
                byte[]bytes=new byte[128];
                FileOutputStream fileOutputStream=new FileOutputStream(file);
                while ((len=inputStream.read(bytes))!=-1){
                    fileOutputStream.write(bytes,0,len);
                }
                fileOutputStream.flush();
                fileOutputStream.close();
                inputStream.close();

            }
        });
    }
}