dependencies{

    ...

    compile 'io.reactivex:rxjava:1.2.0'

    compile 'io.reactivex:rxandroid:1.2.1'

    compile 'com.squareup.retrofit2:retorfit:2.1.0'

    compile 'com.squareup.retrofit2:converter-gson:2.1.0'

    compile 'com.squareup.retrofit2:adapter-rxjava:2.1.0'

}

public interface IpServiceForPost{

    @FormUrlEncoded

    @POST("getIpInfo.php")

    Observable<IpModel> getIpMsg(@Field("ip") String first);

}

private void postIpInformation(String ip){

    String url = "http://ip.taobao.com/service/";

    Retrofit retrofit = new Retrofit.Builder().baseUrl(url).addConverterFactory(GsonConverterFactory.create())

    .addCallAdapterFactory(RxJavaCallAdapterFactory.create()).build();

    IpServiceForPost ipService = retrofit.create(IpServcieForPost.class);

    subscription=ipService.getIpMsg(ip).subscribeOn(Schedulers.io()).observeOn(AndroidSchedulers.mainThread())

    .subscribe(new Subscriber<IpModel>(){

        @Override

        public void onCompleted(){

            Log.d(TAG,"onCompleted");

        }

        @Override

        public void onError(Throwable e){

            Log.d(TAG,"onError");

        }

        @Override

        public void onNext(IpModel ipModel){

            String country=ipModel.getData().getCountry();

            Toast.makeText(getApplicationContext(),country,Toast.LENGTH_SHORT).show();

        }

    });

}

public class IpModel{

    private int code;

    private IpData data;

    public void setCode(int code){

        this.code = code;

    }

    public int getCode(){

        return this.code;

    }

    ...

}

public class HttpResult<T>{

    private int code;

    private T data;

    public int getCode(){

        return code;

    }

    public void setCode(int code){

        this.code = code;

    }

    public T getData(){

        return data;

    }

    public void setData(T data){

        this.data = data;

    }

}

public interface IpServiceForPost{

    @FormUrlEncoded

    @POST("getIpInfo.php")

    Observable<HttpResult<IpData>> getIpMsg(@Field("ip") String first);

}

private void postIpInformation(String ip){

    ...

    subscription=ipService.getIpMsg(ip).subscribeOn(Schedulers.io())

    .observeOn(AndroidSchedulers.mainThread()).subscribe(new Subscriber<HttpResult<IpData>>(){

        @Override

        public void onCompleted(){

        }

        @Override

        public void onError(Throwable e){

        }

        @Override

        public void onNext(HttpResult<IpData> ipDataHttpResult){

            IpData data=ipDataHttpResult.getData();

            Toast.matkText(getApplicationContext(),data.getCountry(),Toast.LENGTH_SHORT).show();

        }

    });

}

@Override

public void onStop(){

    super.onStop();

    if(subscription!=null && subscription.isUnsubscribed()){

        subscription.unsubscribe();

    }

}

private CompositeSubscription compositeSubscription = new CompositeSubscription();

...

//发送请求的地方，将返回的subscription添加到compositeSubscription中

compositeSubscription.add(subscription);

...

//取消所有请求

@Override

public void onStop(){

    super.onStop();

    compositeSubscription.unsubscribe();

}