okhttp可以用于电脑客户端吗（Okhttp的使用记录）

第一步，添加依赖库'com.squareup.okhttp3:okhttp:3.10.0'

自动下载两个库,OkHttp和Okio,后者是前者的通信基础

第二步,具体用法

创建OkHttpClient实例

实现一个默认的客户端,没有连接时间限制

OkHttpClient client=new OkHttpClient();

实现一个对连接时间读取时间有限制的客户端,超过时间限制,强制失败

OkHttpClient client=new OkHttpClient.builder().connectTimeout(8000, TimeUnit.MILLISECONDS).readTimeout(8000,TimeUnit.MILLISECONDS).build();

发起Http请求(GET)

有同步和异步两种

同步需要自己开一个线程,执行网络连接

创建request请求,并在build()方法前连缀属性;

调用client的newCall()方法创建Call对象;

调用Call对象的excute()方法获取服务器返回的数据response;

返回结果数据格式依赖服务器实现

new Thread(new Runnable() {
@Override
public void run() {
OkHttpClient client=new OkHttpClient.Builder().connectTimeout(8000, TimeUnit.MILLISECONDS).readTimeout(8000,TimeUnit.MILLISECONDS).build();
Request request= new Request.Builder().url(address).build();
try {
Response response=client.newCall(request).execute();
if (response.body() != null) {
String strResponse = response.body().string();
}
} catch (IOException e) {
e.printStackTrace();
}
}
}).start();

异步get请求,因为onResponse和onFailure()默认开启子线程,需要更新UI时,需要跳转主UI线程

OkHttpClient client=new OkHttpClient.Builder().connectTimeout(8000, TimeUnit.MILLISECONDS).readTimeout(8000,TimeUnit.MILLISECONDS).build();
Request request= new Request.Builder().url(address).build();
client.newCall(request).enqueue(new callback() {
@Override
public void onFailure(Call call, IOException e) {
// do something
Log.d("http connect","失败");
Log.d("http connect","e" e.toString());
}
@Override
public void onResponse(Call call, Response response) throws IOException {
if (response.isSuccessful()){
// do something
Log.d("http connect","获取数据");
Log.d("http connect","response.code()==" response.code());
Log.d("http connect","response.body().string()==" response.body().string());
}
}
});

发起POST请求

创建RequestBody对象来存放待提交数据;

新建request请求,在build()前调用post()方法,并把body对象传入;

后续操作与get并没有区别

OkHttpClient client=new OkHttpClient.Builder().connectTimeout(8000, TimeUnit.MILLISECONDS).readTimeout(8000,TimeUnit.MILLISECONDS).build();
RequestBody body=new FormBody.Builder().add("account",account).add("password",password).build();
Request request= new Request.Builder().url(address).post(body).build();
client.newCall(request).enqueue(new Callback() {
@Override
public void onFailure(Call call, IOException e) {
// do something
Log.d("http connect","失败");
Log.d("http connect","e" e.toString());
}
@Override
public void onResponse(Call call, Response response) throws IOException {
if (response.isSuccessful()){
// do something
Log.d("http connect","获取数据");
Log.d("http connect","response.code()==" response.code());
Log.d("http connect","response.body().string()==" response.body().string());
}
}
});

response.code(),这个是http协议自带的,200表示连接成功

response.body().string()要放在子线程,且只执行一次

做一个小小的封装

public class OkHttpUtils {
private static OkHttpClient client ;
private static final String TAG = "OkHttpUtils";
private static ConcurrentHashMap<String, List<Cookie>> cookiestore = new ConcurrentHashMap<>();
//单例模式返回一个实例
public static OkHttpClient getInstance(){
if (client==null)
synchronized (OkHttpClient.class){
if (client==null){
//添加cookieJar,自动化管理cookie,获得一致的sessions值
//添加连接超时和读取超时,在网络状况不好的时候可以做出提示.
client=new OkHttpClient.Builder().cookieJar(new CookieJar() {
@Override
public void saveFromResponse(HttpUrl url, List<Cookie> cookies) {
Log.i(TAG, "saveFromResponse: cookies=" cookies);
Log.i(TAG, "saveFromResponse: cookieStore=" cookieStore.size());
cookieStore.put(url.host(), cookies);
}
@Override
public List<Cookie> loadForRequest(HttpUrl url) {
List<Cookie> cookies = cookieStore.get(url.host());
Log.i(TAG, "loadForRequest: cookies=" cookies);
return cookies != null ? cookies : new ArrayList<Cookie>();
}
}).connectTimeout(8000, TimeUnit.MILLISECONDS).readTimeout(8000,TimeUnit.MILLISECONDS).build();
}
}
return client;
}
//封装了一个静态方法.用来实现登录,url是你要访问的网址或者接口.在使用时可以通过匿名类,根据实际情况实现一个callback,在callback方法中,分别对成功和失败做处理
public static void sendHttpLoginRequest( String account, String password, Callback callback) {
OkHttpClient client=OkHttpUtils.getInstance();
RequestBody body=new FormBody.Builder().add("account",account).add("password",password).build();
Request request= new Request.Builder().url("url").post(body).build();
client.newCall(request).enqueue(callback);
}
}

下面实际使用下,demo,点击获取按钮,会把获取到的信息设置到TextView中

public class Main2Activity extends AppCompatActivity implements View.OnClickListener{
private TextView mContent;
private Button bInsquire;
private Button bInfor;
private Button bModifyPhone;
private static final String TAG = "Main2Activity";
//定义常量
public static final int GET_CONTACT=1;
public static final int GET_INFOR=2;
public static final int MODIFY_PHONE=3;
//定义一个内部Handler,用来获取callback发送的消息,重写内部方法,并处理消息
private Handler handler=new Handler(){
@Override
public void handleMessage(Message msg) {
if (msg!=null){
switch (msg.what){
case GET_CONTACT:
mContent.setText((String)msg.obj);
case GET_INFOR:
mContent.setText((String)msg.obj);
case MODIFY_PHONE:
mContent.setText((String)msg.obj);
}
}else{
Log.i(TAG, "hanlderNews: msg null");
}
}
});
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main2);
mContent=findViewById(R.id.tv_content);
bInsquire=findViewById(R.id.b_inquire_contacts);
bInfor=findViewById(R.id.b_Information);
bModifyPhone=findViewById(R.id.b_modify_phone);
bInsquire.setOnClickListener(this);
bInfor.setOnClickListener(this);
bModifyPhone.setOnClickListener(this);
}
@Override
public void onClick(View view) {
switch (view.getId()){
case R.id.b_inquire_contacts:
Log.i(TAG, "onClick: bInsquire");
//匿名类,重写了失败和成功的处理,成功的时候,给Handler发送消息,消息内容为获得的相应体Response的内容
OkHttpUtils.sendHttpContactsRequest(new Callback() {
@Override
public void onFailure(Call call, IOException e) {
Log.i(TAG, "onFailure: connect failed");
}
@Override
public void onResponse(Call call, Response response) throws IOException {
if (response!=null){
String strResponse=response.body().string();
Log.d("http connect","response.code()==" response.code());
Log.d("http connect","response.body().toString()==" strResponse);
Message msg=Message.obtain();
msg.what=GET_CONTACT;
msg.obj=strResponse;
mHanlderUtils.sendMessage(msg);
}else {
Log.i(TAG, "onResponse: response failed");
}
}
});
break;
case R.id.b_Information:
case R.id.b_modify_phone:
}
}
}

注意,在新建Handler的时候,AS3.0版本以后会出现告警信息

This Handler class should be static or leaks might occur (anonymous android.os.Handler)

这是由于handler获取到activity的引用,可能由于消息处理的不及时,延时任务会导致activity不能被成功finish(),出现内存泄漏的风险,这里参考 https://blog.csdn.net/banxiali/article/details/51494842

对hanlder进行封装,持有当前活动的弱引用,由于封装的hanlder会处理不同的message,所以在封装Handler的handlerMessage()方法中回调接口方法,在不同的活动里根据情况实现这个接口即可

接口方法

public interface HandlerNewsInterface {
void hanlderNews(Message msg);
}

封装handler

public class HandlerUtils extends Handler {
private WeakReference<Activity> mActivityReference;
private HandlerNewsInterface mHanlderNews;
HandlerUtils(Activity mActivity,HandlerNewsInterface mHanlderNews) {
this.mActivityReference = new WeakReference<>(mActivity);
this.mHanlderNews=mHanlderNews;
}
@Override
public void handleMessage(Message msg) {
mHanlderNews.hanlderNews(msg);
super.handleMessage(msg);
}
}

所以上面的Demo中的Handler就可以这样实现

private HandlerUtils mHanlderUtils=new HandlerUtils(this, new HandlerNewsInterface() {
@Override
public void hanlderNews(Message msg) {
if (msg!=null){
switch (msg.what){
case GET_CONTACT:
mContent.setText((String)msg.obj);
case GET_INFOR:
mContent.setText((String)msg.obj);
case MODIFY_PHONE:
mContent.setText((String)msg.obj);
}
}else{
Log.i(TAG, "hanlderNews: msg null");
}
}
});

记得要在活动消失前,移除hanlder中添加的消息

@Override
protected void onDestroy() {
mHandlerUtils.removeMessages(GET_CONTACT);
mHandlerUtils.removeMessages(GET_INFOR);
mHandlerUtils.removeMessages(MODIFY_PHONE);
super.onDestroy();
}

注意,

A.网络请求,需要在配置文件中声明权限

记得在AndroidManifest.xml中配置网络权限。

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

B.对okhttp进行底层封装

对okHttp的更多用法,参考

https://www.jianshu.com/p/ef9282217d07

1.单例模式,获取客户端实例保证

这个唯一的实例,可以在初始化时就设置连接超时,读取超时和写入超时,cookieJar自动管理cookie,可以设置缓存大小和目录

2 对网络连接超时和读取超时的处理

首先,在设置客户端的时候,我们在build()方法中添加了connectTimOut()和ReadTimeOut()方法,添加了超时属性

接下来,在callBack中返回失败的接口中分情况处理

@Override
public void onFailure(Call call, IOException e) {
// do something
Log.d("http connect","失败");
//连接失败,一般是没有网络或者服务器问题
if (e instanceof ConnectException){
Log.d("http connect","ConnectException e=" e.toString());
}
//超时异常,一般是网络不好,可以设置重连以及重连次数
if (e instanceof SocketTimeoutException){
Log.d("http connect","SocketTimeoutException e=" e.toString());
}
}

3 psot数据的类型

表单数据(键值对)

RequestBody body=new FormBody.Builder().add("pwd",pwd).add("newPwd1",new1).add("newPwd2",new2).build();

json数组

//设置媒体类型。application/json表示传递的是一个json格式的对象
MediaType mediaType = MediaType.parse("application/json");
//使用JSONObject封装参数
JSONObject jsonObject = new JSONObject();
try {
jsonObject.put("参数名","参数值");
} catch (JSONException e) {
e.printStackTrace();
}
//创建RequestBody对象，将参数按照指定的MediaType封装
RequestBody requestBody = RequestBody.create(mediaType,jsonObject.toString());

更多的媒体类型(MediaType)信息 https://baike.baidu.com/item/Internet Media Type?fr=aladdin

图片格式参考https://blog.csdn.net/zhan10001/article/details/78461143

private void sendMessage(String fileName,File file) {
RequestBody requestBody = new MultipartBody.Builder()
.setType(MultipartBody.FORM)
.addFormDataPart("headPic", fileName,
RequestBody.create(MediaType.parse("image/jpg"), file))
.build();
OkHttpClient client=OkHttp3Utils.getInstance();
Request request=new Request.Builder().url(DataUtil.ModifyHeadPic).post(requestBody).build();
client.newCall(request).enqueue(new Callback() {
@Override
public void onFailure(Call call, IOException e) {
Log.i(TAG, "onFailure: failed");
}
@Override
public void onResponse(Call call, Response response) throws IOException {
if (response.isSuccessful()){
String result=response.body().string();
Log.i(TAG, "onResponse: result=" result);
}
}
});