时间：2020-12-18 02:07:53 | 栏目：Android代码 | 点击：次
Android系统提供了两种HTTP通信类，HttpURLConnection和HttpClient。
尽管Google在大部分安卓版本中推荐使用HttpURLConnection，但是这个类相比HttpClient实在是太难用，太弱爆了。
OkHttp是一个相对成熟的解决方案，据说Android4.4的源码中可以看到HttpURLConnection已经替换成OkHttp实现了。所以我们更有理由相信OkHttp的强大。
使用范围
OkHttp支持Android 2.3及其以上版本。
对于Java, JDK1.7以上。
基本使用
HTTP GET
OkHttpClient client = new OkHttpClient();
String run(String url) throws IOException {
Request request = new Request.Builder().url(url).build();
Response response = client.newCall(request).execute();
if (response.isSuccessful()) {
return response.body().string();
} else {
throw new IOException("Unexpected code " + response);
}
}
Request是OkHttp中访问的请求，Builder是辅助类。Response即OkHttp中的响应。
Response类：
public boolean isSuccessful() Returns true if the code is in [200..300), which means the request was successfully received, understood, and accepted.
response.body()返回ResponseBody类
可以方便的获取string
public final String string() throws IOException Returns the response as a string decoded with the charset of the Content-Type header. If that header is either absent or lacks a charset, this will attempt to decode the response body as UTF-8. Throws: IOException
当然也能获取到流的形式：
public final InputStream byteStream()
HTTP POST
POST提交Json数据
public static final MediaType JSON = MediaType.parse("application/json; charset=utf-8");
OkHttpClient client = new OkHttpClient();
String post(String url, String json) throws IOException {
RequestBody body = RequestBody.create(JSON, json);
Request request = new Request.Builder()
.url(url)
.post(body)
.build();
Response response = client.newCall(request).execute();
f (response.isSuccessful()) {
return response.body().string();
} else {
throw new IOException("Unexpected code " + response);
}
}
使用Request的post方法来提交请求体RequestBody
POST提交键值对
很多时候我们会需要通过POST方式把键值对数据传送到服务器。 OkHttp提供了很方便的方式来做这件事情。
OkHttpClient client = new OkHttpClient();
String post(String url, String json) throws IOException {
RequestBody formBody = new FormEncodingBuilder()
.add("platform", "android")
.add("name", "bug")
.add("subject", "XXXXXXXXXXXXXXX")
.build();
Request request = new Request.Builder()
.url(url)
.post(body)
.build();
Response response = client.newCall(request).execute();
if (response.isSuccessful()) {
return response.body().string();
} else {
throw new IOException("Unexpected code " + response);
}
}
注意：
import java.io.IOException;
import java.util.List;
import java.util.concurrent.TimeUnit;
import org.apache.http.client.utils.URLEncodedUtils;
import org.apache.http.message.BasicNameValuePair;
import cn.wiz.sdk.constant.WizConstant;
import com.squareup.okhttp.Callback;
import com.squareup.okhttp.OkHttpClient;
import com.squareup.okhttp.Request;
import com.squareup.okhttp.Response;
public class OkHttpUtil {
private static final OkHttpClient mOkHttpClient = new OkHttpClient();
static{
mOkHttpClient.setConnectTimeout(30, TimeUnit.SECONDS);
}
/**
* 该不会开启异步线程。
* @param request
* @return
* @throws IOException
*/
public static Response execute(Request request) throws IOException{
return mOkHttpClient.newCall(request).execute();
}
/**
* 开启异步线程访问网络
* @param request
* @param responseCallback
*/
public static void enqueue(Request request, Callback responseCallback){
mOkHttpClient.newCall(request).enqueue(responseCallback);
}
/**
* 开启异步线程访问网络, 且不在意返回结果（实现空callback）
* @param request
*/
public static void enqueue(Request request){
mOkHttpClient.newCall(request).enqueue(new Callback() {
@Override
public void onResponse(Response arg0) throws IOException {
}
@Override
public void onFailure(Request arg0, IOException arg1) {
}
});
}
public static String getStringFromServer(String url) throws IOException{
Request request = new Request.Builder().url(url).build();
Response response = execute(request);
if (response.isSuccessful()) {
String responseUrl = response.body().string();
return responseUrl;
} else {
throw new IOException("Unexpected code " + response);
}
}
private static final String CHARSET_NAME = "UTF-8";
/**
* 这里使用了HttpClinet的API。只是为了方便
* @param params
* @return
*/
public static String formatParams(List<BasicNameValuePair> params){
return URLEncodedUtils.format(params, CHARSET_NAME);
}
/**
* 为HttpGet 的 url 方便的添加多个name value 参数。
* @param url
* @param params
* @return
*/
public static String attachHttpGetParams(String url, List<BasicNameValuePair> params){
return url + "?" + formatParams(params);
}
/**
* 为HttpGet 的 url 方便的添加1个name value 参数。
* @param url
* @param name
* @param value
* @return
*/
public static String attachHttpGetParam(String url, String name, String value){
return url + "?" + name + "=" + value;
}
}
总结
通过上面的例子我们可以发现，OkHttp在很多时候使用都是很方便的，而且很多代码也有重复，因此特地整理了下面的工具类。