General overview

Simple create A GET request POST request Download (display progress) Upload (display progress) OthersCopy the code

OkHttp is an open source project that handles web requests; Android lightweight framework; Used to replace HttpUrlConnection and Apache HttpClient;

The preparatory work

Add the dependent

/ / network request OkHttp3 implementation 'com. Squareup. OkHttp3: okhttp: 4.3.1'Copy the code

Setting Network Permissions

<uses-permission android:name="android.permission.INTERNET" />
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For mobile phones with API level 28 or higher, an error message is displayed during HTTP requests (non-HTTPS requests) and no data is requested.

CLEARTEXT communication to www.baidu.com not permitted by network security policy
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Need in the application of AndroidManifest set android: usesCleartextTraffic = “true”

create

Okhttp provides both synchronous and asynchronous request methods, which are Not very different. When a synchronous request is made, the thread is blocked during the request. It is Not recommended to run it in the main thread.

Simple creation in four steps

Create a Request object (OkHttpClient); create a Request object (OkHttpClient); create a Call object (call.enqueue()); Call call.execute () to perform the synchronization requestCopy the code

An asynchronous request

OkHttpClient client = new OkHttpClient();	// instantiate the OkHttpClient object
Request request = new Request.Builder()		// Create the Builder mode for the Request object
		.url("http://www.baidu.com")	// Set the url to access
		//.get() // Set to GET request The default is GET request and can be ignored
		.build();	// Create a Request object
Call call = client.newCall(request);	// Construct a Call object from the request object
call.enqueue(new Callback() {	// Call the call enqueue() to make an asynchronous request
	@Override
	public void onFailure(Call call, IOException e) {
		LLDB error message () : LLDB error message (
		Log.d("onFailure"."onFailure: "+e.getMessage());
	}

	@Override
	public void onResponse(Call call, Response response) throws IOException {
		// Successful callback, where we can get the data returned by the server
		Log.d("onResponse"."onResponse: "+response.body().string()); }});Copy the code

A synchronous request

OkHttpClient client = new OkHttpClient();
Request request = new Request.Builder()
         .url("http://www.baidu.com")
         .get()
         .build();
 Call call = client.newCall(request);
 Response response = null; 
 try {
     response = call .execute();Execute () of the call is blocked during the request process. It is recommended to write to the child thread
     Log.d("onResponse"."onResponse: "+response.body().string());
 } catch (IOException e) {
     e.printStackTrace();
     Log.d("onFailure"."onFailure: "+e.getMessage());
 }
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The onResponse callback has an argument that response is the response data. If the data returned is a string, you can get it from Response.body ().string(). If the data returned is a binary byte array, Response.body ().bytes() If the data returned is an inputStream, it can be response.body().bytestream ()Copy the code

Suspend the request

Abort by calling call cancel() to stop calling call.cancel();

Detailed introduction

OkHttp supports PUT, DELETE, POST, and GET requests. The following files are uploaded and downloaded using asynchronous requests

A GET request

GET requests are relatively simple, consisting of the four simple steps above

OkHttpClient client = new OkHttpClient();
Request request = new Request.Builder()
		.url("")
		.get()
		.build();
Call call = client.newCall(request);
call.enqueue(new Callback() {
	@Override
	public void onFailure(@NotNull Call call, @NotNull IOException e) {}@Override
	public void onResponse(@NotNull Call call, @NotNull Response response) throws IOException {}});Copy the code

A POST request

POST requests support simple POST requests (submit forms) for files, streams, strings, forms, etc.

OkHttpClient client = new OkHttpClient();
RequestBody requestBody = new FormBody.Builder()// Create form
		.add("key"."value")		// Pass in the data to commit
		.add("key"."value")		// Pass in the data to commit
		.build();		// Create the request body
Request request = new Request.Builder()	
		.url("")		// Set the url for submitting data
		.post(requestBody)	// Set it to POST, passing in the request body
		.build();
Call call = client.newCall(request);
call.enqueue(new Callback() {	// Asynchronous request
	@Override
	public void onFailure(@NotNull Call call, @NotNull IOException e) {}@Override
	public void onResponse(@NotNull Call call, @NotNull Response response) throws IOException {}});Copy the code

Download (save to local)

A GET request or a POST request simply converts the returned data to a stream (response.body().bytestream ()) and saves it locally via InputStream() and OutputStream().

Simple download request (example)

OkHttpClient client = new OkHttpClient();
Request request = new Request.Builder()
        .url("http://image.baidu.com/search/down?tn=download&ipn=dwnl&word=download" +
                        "&ie=utf8&fr=result&url=http%3A%2F%2Fc.hiphotos.baidu.com%2Fzhidao%2" +
                        "Fpic%2Fitem%2Fd009b3de9c82d1587e249850820a19d8bd3e42a9.jpg&thumburl=" +
                        "http%3A%2F%2Fimg1.imgtn.bdimg.com%2Fit%2Fu%3D3675415932%2C4054970339%26" +
                        "fm%3D26%26gp%3D0.jpg")	// Picture on Baidu
        .get()
        .build();
Call call = client.newCall(request);
call.enqueue(new Callback() {
    @Override
    public void onFailure(@NotNull Call call, @NotNull IOException e) {
		Log.d("onFailure"."onFailure: " + e.getMessage());
    }
    @Override
    public void onResponse(@NotNull Call call, @NotNull Response response) throws IOException {
        String path = Environment.getExternalStorageDirectory().getPath()+"/Download";// File path, root directory Download directory
        File file = new File(path,"image.jpg");// Set the path and name of the file
        InputStream is = response.body().byteStream();
        BufferedInputStream bis = new BufferedInputStream(is);
        FileOutputStream fos = new FileOutputStream(new File(path));
        byte[] bytes = new byte[1024];
        int len;
        Log.d("onResponse"."OnResponse: started");
        while((len=is.read(bytes))! = -1){
            fos.write(bytes,0,len);
        }
        fos.flush();
        Log.d("onResponse"."OnResponse: end"); is.close(); bis.close(); fos.close(); }});Copy the code

The preparatory work

Permission Obtain Indicates the access permission of the SD card

<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
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In Android 6.0, Google introduced the permission application mechanism, which requires dynamic permission application and user authorization to use dangerous permissions. Access permissions are hazard permissions.

How do I get it dynamically? A utility class is provided for dynamic authorization

public class PermissionUtil {
    public static String READ_EXTERNAL_STORAGE = Manifest.permission.READ_EXTERNAL_STORAGE;     // Memory read
    public static String WRITE_EXTERNAL_STORAGE = Manifest.permission.WRITE_EXTERNAL_STORAGE;   // Memory write
    
    public static void getPermissions(Activity activity, String... permission) {
        
        List<String> permissions = new ArrayList<>();
        // Apply for dynamic permission here
        // Check whether the system is greater than or equal to Android 6.0
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
            for(int i=0; i<permission.length; i++){int request = ContextCompat.checkSelfPermission(activity, permission[i]);
                // Check whether the permission is not obtained
                if(request ! = PackageManager.PERMISSION_GRANTED) permissions.add(permission[i]); }if (permissions.size()>0) {// Lack of permission, apply for permission
                // Current context; An array of permissions; A unique request code (16 digits from 0 to 65535)
                ActivityCompat.requestPermissions(activity,  permissions.toArray(new String[permissions.size()]), 0XFF);
            } else {
                // Permission permission is fully authorized}}else {
            // No dynamic authorization is required below API 23}}}Copy the code

Used in MainActivity onCreate() for dynamic authorization

PermissionUtil.getPermissions(this, PermissionUtil.READ_EXTERNAL_STORAGE, PermissionUtil.WRITE_EXTERNAL_STORAGE);
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Display download progress

There are two ways to display the download progress:

Get it in real time in the onResponse callback
Proxy the network response ResponseBody

The first is relatively simple (currently available only and may not work when combined with other frameworks, e.g. Retrofit+OkHttp3+RxJava2 will not work when combined due to Retrofit)

The second is a bit more complicated, involving interceptors and directly pasting code

Second: proxy activity_main for ResponseBody

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:gravity="center"
    android:orientation="vertical">

    <ProgressBar
        android:id="@+id/progressBar"
        style="? android:attr/progressBarStyleHorizontal"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"/>

    <Button
        android:id="@+id/button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="10dp"
        android:text="Download" />
</LinearLayout>
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MainActivity

public class MainActivity extends AppCompatActivity {

    private ProgressBar progressBar;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        //Android 6.0 and above requires dynamic application. The PermissionUtil tool has been posted above
        PermissionUtil.getPermissions(this, PermissionUtil.READ_EXTERNAL_STORAGE, PermissionUtil.WRITE_EXTERNAL_STORAGE);

        progressBar = findViewById(R.id.progressBar);
        // Set the button click event
        findViewById(R.id.button).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                download();// Click to download}}); }public void download(a){
        String path = Environment.getExternalStorageDirectory().getPath() + "/Download/qq.exe";// Save path and file name
        String url = "https://qd.myapp.com/myapp/qqteam/pcqq/PCQQ2020.exe";// Here is the QQPC version download address, the file is large
        // Set the download path and url to start the download
        OkHttpHelper.getInstance().setDownloadUrl(url).startDownload(path,new OkHttpHelper.DownloadCallback() {
            @Override
            public void start(final long max) {
            	// This is a child thread and needs to go back to the main thread to update the UI
                progressBar.post(new Runnable() {
                    @Override
                    public void run(a) {
                        Toast.makeText(MainActivity.this."Start downloading", Toast.LENGTH_SHORT).show();
                        progressBar.setMax((int) max); }}); }@Override
            public void loading(final long progress) {
                progressBar.post(new Runnable() {
                    @Override
                    public void run(a) {
                        progressBar.setProgress((int) progress); }}); }@Override
            public void complete(String msg) {}@Override
            public void fail(String message) {}}); }}Copy the code

OkHttpHelper

public class OkHttpHelper {
    private OkHttpClient client;
    private Request request;

    private static OkHttpHelper instance = null;
    private OkHttpHelper(a) {
        initOkHttp();/ / initialization
    }

    static OkHttpHelper getInstance(a) {// Singleton mode
        if (instance == null) {
            synchronized (OkHttpHelper.class) {
                if (instance == null) {
                    instance = newOkHttpHelper(); }}}return instance;
    }

    private void initOkHttp(a) {
        client = new OkHttpClient.Builder()
                .connectTimeout(30, TimeUnit.SECONDS)
                .readTimeout(30, TimeUnit.SECONDS)
                .writeTimeout(30, TimeUnit.SECONDS)
                .build();
    }
    // Set GET request, set download url
    OkHttpHelper setDownloadUrl(String url) {
        request = new Request.Builder()
                .url(url)
                //. Header ("RANGE","")//
                .get()
                .build();
        return this;
    }
    // Set the download path and start the download
    public void startDownload(final String path,final DownloadCallback callback) {
        if (client == null) {
            initOkHttp();
        }
        OkHttpClient okHttpClient = client.newBuilder().addInterceptor(new MyInterceptor(callback)).build();Insert a custom MyInterceptor() interceptor
        Call call = okHttpClient.newCall(request);
        call.enqueue(new Callback() {
            @Override
            public void onFailure(@NotNull Call call, @NotNull IOException e) {
                callback.fail(e.getMessage());
            }

            @Override
            public void onResponse(@NotNull Call call, @NotNull Response response) throws IOException {
                download(response,path);
                callback.complete("Complete"); }}); }// Create MyInterceptor class to implement Interceptor
    static class MyInterceptor implements Interceptor {
        DownloadCallback callback;
        public MyInterceptor(DownloadCallback callback) {
            super(a);this.callback = callback;
        }

        @NotNull
        @Override
        public Response intercept(@NotNull Chain chain) throws IOException {
            Response response = chain.proceed(chain.request());
            return response.newBuilder().body(newMyResponseBody(response,callback)).build(); }}// Create MyResponseBody and inherit from ResponseBody
    static class MyResponseBody extends ResponseBody {
        Response response;
        DownloadCallback callback;

        MyResponseBody(Response response,DownloadCallback callback) {
            super(a);this.response = response;
            this.callback = callback;
        }

        @Override
        public long contentLength(a) {
            // Get the total number of bytes of the file
            callback.start(response.body().contentLength());
            return response.body().contentLength();
        }

        @Nullable
        @Override
        public MediaType contentType(a) {
            // Can get the type of file
            return response.body().contentType();
        }

        @NotNull
        @Override
        public BufferedSource source(a) {
            contentLength();
            contentType();
            // Get file resources
            return Okio.buffer(new ForwardingSource(response.body().source()) {
                long bytesLength=0;
                @Override
                public long read(@NotNull Buffer sink, long byteCount) throws IOException {
                    // Get the download progress
                    final long bytesRead = super.read(sink, byteCount);
                    bytesLength += bytesRead;
                    callback.loading(bytesLength);
                    returnbytesRead; }}); }}/ / note: the three interfaces in the MyResponseBody contentLength, contentType, source, call on their own will not follow, need artificial passive implementation;
    InputStream is = Response.body ().bytestream (); "Will be called;
    // Then we call the contentLength(),contentType() methods ourselves,
    InputStream is = response.body().bytestream (); Add two lines of response.body().contentLength(); ,response.body().contentType();
    // Download, perform download, save
    public static void download(Response response,String path) throws IOException {
        //response.body().contentLength();
        //response.body().contentType();
        InputStream is = response.body().byteStream();// Get the resource and turn it into a byte stream
        BufferedInputStream bis = new BufferedInputStream(is);
        FileOutputStream fos = new FileOutputStream(new File(path));// Set the location and file to save
        byte[] bytes = new byte[1024];
        int len;
        while((len = is.read(bytes)) ! = -1) {
            fos.write(bytes, 0, len);/ / save
        }
        fos.flush();
        is.close();
        bis.close();
        fos.close();
    }
    // Some necessary interfaces
    public interface DownloadCallback {	// Various interfaces required for downloading
        // Start downloading
        void start(long max);			// Total number of bytes of the incoming file
        // Downloading
        void loading(long progress);	// Pass in the number of bytes downloaded
        // Download complete
        void complete(String msg);		// Pass a success message
        // The request failed
        void fail( String message);		// An error message was passed in}}Copy the code

MyResponseBody (); MyResponseBody (); MyResponseBody (); InputStream is = Response.body ().bytestream (); “Will be called; 3. Then we call contentLength() and contentType() ourselves; 4, Or we can add two lines of response.body().contentLength() to the Download method; ,response.body().contentType(); , will also be executed.

The first is to get the modification OkHttpHelper in real time in the onResponse callback

public class OkHttpHelper {
    private static OkHttpHelper instance = null;
    private OkHttpClient client;
    private Request request;

    private OkHttpHelper(a) {
        initOkHttp();/ / initialization
    }

    static OkHttpHelper getInstance(a) {// Singleton mode
        if (instance == null) {
            synchronized (OkHttpHelper.class) {
                if (instance == null) {
                    instance = newOkHttpHelper(); }}}return instance;
    }

    OkHttpHelper setDownloadUrl(String url) {
        request = new Request.Builder()
                .url(url)
                //. Header ("RANGE","")//
                .get()
                .build();
        return this;
    }

    private void initOkHttp(a) {
        client = new OkHttpClient.Builder()
                .connectTimeout(30, TimeUnit.SECONDS)
                .readTimeout(30, TimeUnit.SECONDS)
                .writeTimeout(30, TimeUnit.SECONDS)
                .build();
    }

    void startDownload(final String path, final DownloadCallback callback) {
        if (client == null) {
            initOkHttp();
        }
        Call call = client.newCall(request);
        call.enqueue(new Callback() {
            @Override
            public void onFailure(@NotNull Call call, @NotNull IOException e) {
                callback.fail(e.getMessage());
            }

            @Override
            public void onResponse(@NotNull Call call, @NotNull Response response) throws IOException {
                downlaod(response, path, callback);
                callback.complete("Complete"); }}); }public static void downlaod(Response response, String path, DownloadCallback callback) throws IOException {
        long max = response.body().contentLength();
        callback.start(max);
        InputStream is = response.body().byteStream();
        BufferedInputStream bis = new BufferedInputStream(is);
        FileOutputStream fos = new FileOutputStream(new File(path));
        byte[] bytes = new byte[1024];
        int len;
        long length = 0;// Record the number of bytes downloaded
        while((len = is.read(bytes)) ! = -1) {
            length += len;
            fos.write(bytes, 0, len);
            callback.loading(length);
        }
        fos.flush();
        is.close();
        bis.close();
        fos.close();
    }

    public interface DownloadCallback {
        // Start downloading
        void start(long max);// Total number of bytes of the incoming file

        // Downloading
        void loading(long progress);// Pass in the number of bytes downloaded

        // Download complete
        void complete(String msg);

        // The request failed
        void fail(String message); }}Copy the code

upload

File upload

Parse ("text/plain; Charset = UTF-8 ") text/ HTML HTML text/plain Text Document Text/XML XML image/ GIF GIF image/ JPEG JPG image/ PNG PNG Application /xhtml-xml XHTML application/json json application/ PDF PDF application/msword Word Document Application/OCtet-stream Binary streamCopy the code

File upload (simple example)

OkHttpClient client = new OkHttpClient();/ / instantiate
// Get the uploaded file
File file = new File(Environment.getExternalStorageDirectory(),"/Download/qq.exe");
// Set the upload type
MediaType type = MediaType.parse("");
// Set the request body
RequestBody body = new MultipartBody.Builder()
		.setType(MultipartBody.FORM)
		.addFormDataPart(""."")
		// Put the file type and file into the request body
		.addFormDataPart(""."",RequestBody.create(file, type))
		.build();
//RequestBody body = RequestBody.create(file, type);
// Set the url to upload (to support upload url) into the request body
Request request = new Request.Builder()
		.url("")
		.post(body)
		.build();
Call call = client.newCall(request);
call.enqueue(new Callback() {// Asynchronous request
	@Override
	public void onFailure(@NotNull Call call, @NotNull IOException e) {}@Override
	public void onResponse(@NotNull Call call, @NotNull Response response) throws IOException {}});Copy the code

Classes and methods involved

new RequestBody(); RequestBody.create(byte[]); RequestBody.create(File, MediaType); Requestbody.create (byte[], MediaType); // Use requestBody.create (String, MediaType) to upload binary bytes; // Use requestBody.create (ByteString, MediaType) to upload text; Requestbody.create (byte[], MediaType,int offset); // offset Uploads requestBody. create(byte[], MediaType,int offset,int byteCount); // offset, byteCount starts at offset, and ends at offset. Upload new MultipartBody(); new MultipartBody.Builder(); builder.setType(MediaType); //MultipartBody.FORM sets the type to FORM Builder. addFormDataPart(String, String); // Add data Builder.addFormDatApart (String, String, RequestBody); // Add the uploaded file and the necessary information builder.build(); // Return RequestBody new MediaType(); MediaType.parse(String); // Set the type of file to uploadCopy the code

Upload monitor (display upload progress)

The web request RequestBody is proxyed

I’m going to go straight to the code

Activity_main ditto

MainActivity

public class MainActivity extends AppCompatActivity {

    private ProgressBar progressBar;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        PermissionUtil.getPermissions(this, PermissionUtil.READ_EXTERNAL_STORAGE, PermissionUtil.WRITE_EXTERNAL_STORAGE);

        progressBar = findViewById(R.id.progressBar);
        findViewById(R.id.button).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) { upload(); }}); }public void upload(a) {
        Map<String, String> map = new HashMap<>();
        String path = Environment.getExternalStorageDirectory().getPath() + "/Download/123.jpg";
        File file = new File(path);
        String url = "";
        OkHttpHelper.getInstance().setUploadUrl(url).startUpload(map, file, new OkHttpHelper.UploadCallback() {
            @Override
            public void start(long max) {}@Override
            public void loading(long progress) {}@Override
            public void complete(String msg) {}@Override
            public void fail(String message) {}}); }}Copy the code

OkHttpHelper

public class OkHttpHelper {
    private static OkHttpHelper instance = null;
    private OkHttpClient client;
    private Request request;

    private OkHttpHelper(a) {
        initOkHttp();/ / initialization
    }

    static OkHttpHelper getInstance(a) {// Singleton mode
        if (instance == null) {
            synchronized (OkHttpHelper.class) {
                if (instance == null) {
                    instance = newOkHttpHelper(); }}}return instance;
    }
    
    public OkHttpHelper setUploadUrl(String url) {
        request = new Request.Builder()
                .url(url)
                .build();
        return this;
    }

    public void startUpload(Map<String, String> map, File file,final UploadCallback callback) {
    	// Refactor the Request body passed in.post()
        Request request = this.request.newBuilder().post(new MyRequestBody(setUploadBody(map, file),callback)).build();
        Call call = client.newCall(request);
        call.enqueue(new Callback() {
            @Override
            public void onFailure(@NotNull Call call, @NotNull IOException e) {
                callback.fail(e.getMessage());
            }

            @Override
            public void onResponse(@NotNull Call call, @NotNull Response response) throws IOException { callback.complete(response.body().string()); }}); }private static class MyRequestBody extends RequestBody {
        RequestBody body = null;
        UploadCallback callback;
        public MyRequestBody(MultipartBody multipartBody, UploadCallback callback) {
            super(a); body = multipartBody;this.callback = callback;
        }

        @Nullable
        @Override
        public MediaType contentType(a) {
            return body.contentType();
        }

        @Override
        public long contentLength(a) throws IOException {
            callback.start(body.contentLength());
            return body.contentLength();
        }

        @Override
        public void writeTo(@NotNull BufferedSink bufferedSink) throws IOException {
            / / packaging
            Sink sk = sink(bufferedSink);
            bufferedSink = Okio.buffer(sk);
            / / write
            body.writeTo(bufferedSink);
            // You must call flush, or the last bit of data may not be written
            bufferedSink.flush();

        }
        /** * write, callback progress interface **@param sink Sink
         * @return Sink
         */
        private Sink sink(Sink sink) {
            return new ForwardingSink(sink) {
                long bytesWritten = 0L;
                @Override
                public void write(Buffer source, long byteCount) throws IOException {
                    super.write(source, byteCount);
                    // Get the upload progressbytesWritten += byteCount; callback.loading(bytesWritten); }}; }}// Package the data to be uploaded
    private MultipartBody setUploadBody(Map<String, String> map, File file) {
        MultipartBody.Builder builder = new MultipartBody.Builder().setType(MultipartBody.FORM);
        RequestBody fileBody = RequestBody.create(file, MediaType.parse("image/png"));
        if(map ! =null && map.size() > 0) {
            for (String key : map.keySet()) {
                String value = map.get(key);
                if(value ! =null) { builder.addFormDataPart(key, value); }}}return builder.addFormDataPart("file"."fileName", fileBody).build();
    }

    public interface UploadCallback {
        // Start uploading
        void start(long max);// Total number of bytes of the incoming file

        // Uploading
        void loading(long progress);// Pass in the number of bytes downloaded

        // Upload complete
        void complete(String msg);

        // The request failed
        void fail(String message); }}Copy the code

other

The interceptor

Interceptors are a powerful mechanism for monitoring, overriding, and retrying calls.

// This is the simplest interceptor
static class MyInterceptor implements Interceptor {
    @NotNull
    @Override
    public Response intercept(@NotNull Chain chain) throws IOException {
        Request request = chain.request();
        Response response = chain.proceed(request);
        return response;
		//return chain.proceed(chain.request());}}// How to use it
OkHttpHelper client = new OkHttpClient.Builder()
		.addInterceptor(new MyInterceptor())		// Register the application interceptor
		.addNetworkInterceptor()// Register a network interceptor
		.build();
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Calling chain.proceed(request) is a key part of every interceptor implementation. This simple approach is where all the HTTP work takes place, generating a response to satisfy the request. If chain.proceed(request) is called multiple times, the previous response body must be closed. (Official translation)

Apply interceptors without worrying about intermediate responses, such as redirects and retries. Even if an HTTP response is provided from the cache, it is always called once. Adhere to the original intent of the application. Do not care about OkHttp injected headers, such as if-none-match. Allows short-circuiting instead of chain.proceed (). Allow retry and call chain.proceed () multiple times.

The network interceptor can operate on intermediate responses such as redirects and retries. Will not be called for cache responses that short-circuit the network. Observe the data as if it were transmitted over a network. Access Connection with a request.

Retry and redirect the interceptor RetryAndFollowUpInterceptor bridge interceptor BridgeInterceptor cache interceptor CacheInterceptor connection interceptor interceptor ConnectInterceptor, speaking, reading and writing CallServerInterceptor

LoggerInterceptor Interceptor prints the header information of network requests. It prints the URL cache of the request :cache-control, max-age= XXX

Classes and methods that may be involved

new Cache(File,long,FileSystem); New Cache(File,long); // Set the number of caches using new OkHttpClient(); newBuilder(); New okHttpClient.builder () Builder.connectTimeout (Long, TimeUnit); //long sets the connection timeout duration, TimeUnit sets the TimeUnit (hour, minute, second) builder.readTimeout(long, TimeUnit); //long sets the read timeout duration, builder.writeTimeout(long, TimeUnit); //long sets the write timeout period, builder.addinterceptor (Interceptor); // Set interceptor builder.cache(cache); // Set the cache builder.build(); // return OkHttpClient new MediaType(); MediaType.parse(String); new RequestBody(); RequestBody.create(byte[]); RequestBody.create(File, MediaType); Requestbody.create (byte[], MediaType); // Use requestBody.create (String, MediaType) to upload binary bytes; // Use requestBody.create (ByteString, MediaType) to upload text; Requestbody.create (byte[], MediaType,int offset); // offset Uploads requestBody. create(byte[], MediaType,int offset,int byteCount); // offset, byteCount starts at offset, ends at offset, uploads new FormBody(); // Set the form new formBody.builder (); formBody.add(String, String); formBody.build(); // Return RequestBody new MultipartBody(); new MultipartBody.Builder(); builder.setType(MediaType); //MultipartBody.FORM sets the type to FORM Builder. addFormDataPart(String, String); // Add data Builder.addFormDatApart (String, String, RequestBody); builder.build(); // Return RequestBody new Request(); new Request.Builder(); builder.url(String); builder.post(RequestBody); builder.addHeader(String, String); Method (String, RequestBody) // set request type (GET,POST) and RequestBody builder.build(); new Call(); call.execute(); Call.enqueue (Callback); // Call call.cancel() asynchronously; // Request to terminate new Response(); response.body(); response.body().string(); response.body().bytes(); response.body().byteStream();Copy the code

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OkHttp3 Getting Started – How to use it

General overview

The preparatory work

Add the dependent

Setting Network Permissions

create

Simple creation in four steps

An asynchronous request

A synchronous request

Suspend the request

Detailed introduction

A GET request

A POST request

Download (save to local)

Simple download request (example)

The preparatory work

Display download progress

upload

File upload

File upload (simple example)

Classes and methods involved

Upload monitor (display upload progress)

other

The interceptor

Classes and methods that may be involved

OkHttp3 Getting Started – How to use it

General overview

The preparatory work

Add the dependent

Setting Network Permissions

create

Simple creation in four steps

An asynchronous request

A synchronous request

Suspend the request

Detailed introduction

A GET request

A POST request

Download (save to local)

Simple download request (example)

The preparatory work

Display download progress

upload

File upload

File upload (simple example)

Classes and methods involved

Upload monitor (display upload progress)

other

The interceptor

Classes and methods that may be involved

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