简介
OkHttp是一款适用于Android和Java应用程序的HTTP&HTTP2客户端。它有如下特性：
- 支持http2，对一台机器的所有请求共享同一个socket
- 内置连接池，支持连接复用，减少延迟
- 支持透明的gzip压缩响应体
- 通过缓存避免重复的请求
- 请求失败时自动重试主机的其他ip，自动重定向
- 好用的API
引入
以Java为例，通常使用Maven构建方式，在pom文件中加入依赖。
<dependency>
<groupId>com.squareup.okhttp3</groupId>
<artifactId>okhttp</artifactId>
<version>3.9.1</version>
</dependency>
get请求
- 先实例化okhttp，构建一个request，由于get是默认方式，所以设置一个url地址就可以了，也可以通过Request.Builder设置更多的参数。
- 然后通过client创建一个call对象并发送请求。
- 通过response.body().string()获取返回的字符串。这个body()其实就是ResponseBody对象。
OkHttpClient client = new OkHttpClient();
Request request = new Request.Builder()
.url(url)
.build();
Response response = client.newCall(request).execute();
String responseBody = response.body().string();
post请求
- 提交字符串
OkHttpClient client = new OkHttpClient();
MediaType mediaType = MediaType.parse("text/plain; charset=utf-8");
String str = "abcd";
RequestBody body = RequestBody.create(mediaType, str);
Request request = new Request.Builder()
.url(url)
.post(body)
.build();
Response response = client.newCall(request).execute();
String responseBody = response.body().string();
- 提交json
OkHttpClient client = new OkHttpClient();
MediaType mediaType = MediaType.parse("application/json; charset=utf-8");
String json = "{'name':'kmt','sex':'man'}";
RequestBody body = RequestBody.create(mediaType, json);
Request request = new Request.Builder()
.url(url)
.post(body)
.build();
Response response = client.newCall(request).execute();
String responseBody = response.body().string();
- 提交form表单
OkHttpClient client = new OkHttpClient();
RequestBody body = new FormBody.Builder()
.add("name", "kmt")
.add("sex", "man")
.build();
Request request = new Request.Builder()
.url(url)
.post(body)
.build();
Response response = client.newCall(request).execute();
String responseBody = response.body().string();
- 上传文件
OkHttpClient client = new OkHttpClient();
MediaType mediaType = MediaType.parse("image/png");
File file = new File("/file/test.png");
RequestBody body = RequestBody.create(mediaType, file);
Request request = new Request.Builder()
.url(url)
.post(body)
.build();
Response response = client.newCall(request).execute();
String responseBody = response.body().string();
- 提交分块请求
OkHttpClient client = new OkHttpClient();
MediaType mediaType = MediaType.parse("image/png");
File file = new File("/file/test.png");
RequestBody fileBody = RequestBody.create(mediaType, file);
RequestBody requestBody = new MultipartBody.Builder()
.setType(MultipartBody.FORM)
.addFormDataPart("file", "test_img", fileBody)
.addFormDataPart("name", "kmt")
.build();
Request request = new Request.Builder()
.url(url)
.post(requestBody)
.build();
Response response = client.newCall(request).execute();
String responseBody = response.body().string();
其他
- 设置超时时间
OkHttpClient client = new OkHttpClient.Builder()
.connectTimeout(10, TimeUnit.SECONDS)
.readTimeout(10,TimeUnit.SECONDS)
.writeTimeout(10,TimeUnit.SECONDS)
.build();
- 添加请求头
Request request = new Request.Builder()
.url(url)
.addHeader("authorization", authorization)
.addHeader("content-type", "application/x-www-form-urlencoded")
.addHeader("cache-control", "no-cache")
.post(body)
.build();
- 异步
client.newCall(request).execute()是同步的，client.newCall(request).enqueue()是异步的。onFailure是请求失败执行的方法，onResponse是请求成功执行的方法。
client.newCall(request).enqueue(new Callback() {
@Override
public void onFailure(Call call, IOException e) {
e.printStackTrace();
}
@Override
public void onResponse(Call call, Response response) throws IOException {
String responseBody = response.body().string();
}
});
