- get请求
OkHttpClient client = new OkHttpClient();
Request request = new Request.Builder()
.url(url)
.build();
Response response = client.newCall(request).execute();
response.body().string();
- post请求
public static final MediaType JSON
= MediaType.parse("application/json; charset=utf-8");
OkHttpClient client = new OkHttpClient();
RequestBody body = RequestBody.create(JSON, json);
Request request = new Request.Builder()
.url(url)
.post(body)
.build();
Response response = client.newCall(request).execute();
response.body().string();
1.1 创建 OkHttpClient 对象
OkHttpClient client = new OkHttpClient();
public OkHttpClient() {
this(new Builder());
}
OkHttpClient(Builder builder) {
this.dispatcher = builder.dispatcher;
this.proxy = builder.proxy;
this.protocols = builder.protocols;
this.connectionSpecs = builder.connectionSpecs;
this.interceptors = Util.immutableList(builder.interceptors);
this.networkInterceptors = Util.immutableList(builder.networkInterceptors);
this.eventListenerFactory = builder.eventListenerFactory;
this.proxySelector = builder.proxySelector;
this.cookieJar = builder.cookieJar;
this.cache = builder.cache;
this.internalCache = builder.internalCache;
this.socketFactory = builder.socketFactory;
boolean isTLS = false;
for (ConnectionSpec spec : connectionSpecs) {
isTLS = isTLS || spec.isTls();
}
if (builder.sslSocketFactory != null || !isTLS) {
this.sslSocketFactory = builder.sslSocketFactory;
this.certificateChainCleaner = builder.certificateChainCleaner;
} else {
X509TrustManager trustManager = systemDefaultTrustManager();
this.sslSocketFactory = systemDefaultSslSocketFactory(trustManager);
this.certificateChainCleaner = CertificateChainCleaner.get(trustManager);
}
this.hostnameVerifier = builder.hostnameVerifier;
this.certificatePinner = builder.certificatePinner.withCertificateChainCleaner(
certificateChainCleaner);
this.proxyAuthenticator = builder.proxyAuthenticator;
this.authenticator = builder.authenticator;
this.connectionPool = builder.connectionPool;
this.dns = builder.dns;
this.followSslRedirects = builder.followSslRedirects;
this.followRedirects = builder.followRedirects;
this.retryOnConnectionFailure = builder.retryOnConnectionFailure;
this.connectTimeout = builder.connectTimeout;
this.readTimeout = builder.readTimeout;
this.writeTimeout = builder.writeTimeout;
this.pingInterval = builder.pingInterval;
if (interceptors.contains(null)) {
throw new IllegalStateException("Null interceptor: " + interceptors);
}
if (networkInterceptors.contains(null)) {
throw new IllegalStateException("Null network interceptor: " + networkInterceptors);
}
}
1.2 创建请求
Request request = new Request.Builder()
.url(url)
.build();
public static class Builder {
HttpUrl url;
String method;
Headers.Builder headers;
RequestBody body;
Object tag;
public Builder() {
this.method = "GET";
this.headers = new Headers.Builder();
}
Builder(Request request) {
this.url = request.url;
this.method = request.method;
this.body = request.body;
this.tag = request.tag;
this.headers = request.headers.newBuilder();
}
public Builder url(HttpUrl url) {
if (url == null) throw new NullPointerException("url == null");
this.url = url;
return this;
}
...
public Request build() {
if (url == null) throw new IllegalStateException("url == null");
return new Request(this);
}
public final class Request {
final HttpUrl url;
final String method;
final Headers headers;
final @Nullable RequestBody body;
final Object tag;
private volatile CacheControl cacheControl; // Lazily initialized.
Request(Builder builder) {
this.url = builder.url;
this.method = builder.method;
this.headers = builder.headers.build();
this.body = builder.body;
this.tag = builder.tag != null ? builder.tag : this;
}
...
1.3 创建call
Response response = client.newCall(request).execute();
@Override
public Call newCall(Request request) {
return RealCall.newRealCall(this, request, false /* for web socket */);
}
static RealCall newRealCall(OkHttpClient client, Request originalRequest, boolean forWebSocket) {
// Safely publish the Call instance to the EventListener.
RealCall call = new RealCall(client, originalRequest, forWebSocket);
call.eventListener = client.eventListenerFactory().create(call);
return call;
}
1.4 同步网络请求
@Override
public Response execute() throws IOException {
synchronized (this) {
//检查这个 call 是否已经被执行了，每个 call 只能被执行一次，如果想要一个完全一样的 call，可以利用 call#clone 方法进行克隆。
if (executed) throw new IllegalStateException("Already Executed");
executed = true;
}
captureCallStackTrace();
eventListener.callStart(this);
try {
//利用 client.dispatcher().executed(this) 来进行实际执行，dispatcher 是刚才看到的 OkHttpClient.Builder 的成员之一，它的文档说自己是异步 HTTP 请求的执行策略，现在看来，同步请求它也有掺和
client.dispatcher().executed(this);
//调用 getResponseWithInterceptorChain() 函数获取 HTTP 返回结果，从函数名可以看出，这一步还会进行一系列“拦截”操作。
Response result = getResponseWithInterceptorChain();
if (result == null) throw new IOException("Canceled");
return result;
} catch (IOException e) {
//最后还要通知 dispatcher 自己已经执行完毕
eventListener.callFailed(this, e);
throw e;
} finally {
client.dispatcher().finished(this);
}
}
1.5 真正发出网络请求，解析返回结果的 getResponseWithInterceptorChain
Response getResponseWithInterceptorChain() throws IOException {
// Build a full stack of interceptors.
List<Interceptor> interceptors = new ArrayList<>();
interceptors.addAll(client.interceptors());
interceptors.add(retryAndFollowUpInterceptor);
interceptors.add(new BridgeInterceptor(client.cookieJar()));
interceptors.add(new CacheInterceptor(client.internalCache()));
interceptors.add(new ConnectInterceptor(client));
if (!forWebSocket) {
interceptors.addAll(client.networkInterceptors());
}
interceptors.add(new CallServerInterceptor(forWebSocket));
Interceptor.Chain chain = new RealInterceptorChain(interceptors, null, null, null, 0,
originalRequest, this, eventListener, client.connectTimeoutMillis(),
client.readTimeoutMillis(), client.writeTimeoutMillis());
return chain.proceed(originalRequest);
}
1.5.1 在配置 OkHttpClient 时设置的 interceptors；
1.5.2 负责失败重试以及重定向的RetryAndFollowUpInterceptor；
1.5.3 负责把用户构造的请求转换为发送到服务器的请求、把服务器返回的响应转换为用户友好的响应的 BridgeInterceptor；
1.5.4 负责读取缓存直接返回、更新缓存的 CacheInterceptor；
1.5.5 负责和服务器建立连接的 ConnectInterceptor；
1.5.6 配置 OkHttpClient 时设置的 networkInterceptors；
1.5.7 负责向服务器发送请求数据、从服务器读取响应数据的 CallServerInterceptor。
