OkHttpClient

用法1：自定义缓存

OkHttpClient httpclient = new OkHttpClient.Builder()
        .cache(new Cache(new File("cacheDirectory"), new Long(10 * 1024 * 1024)))
        .build();

用法2：当出现缓存冲突时（常用）

OkHttpClient httpclient = new OkHttpClient();

提交请求：

httpclient.newCall(request).enqueue(new Callback() {
    @Override
    public void onFailure(Call call, IOException e) {

    }

    @Override
    public void onResponse(Call call, Response response) throws IOException {

    }
});

用法2：

Response response = httpclient.newCall(request).execute();

Request类

Request request = new Request.Builder()        .url("www.baidu.com")        .header("User-Agent", "OkHttp Header1.java")//键值对，唯一        .header("User-Agent", "OkHttp Header2.java")//再次使用相同字段，值被覆盖        .addHeader("Accept", "application/json; q=0.5")//添加不覆盖，这时又两个“key”,值分别为"value2"、"value3"        .addHeader("Accept", "application/vnd.github.v3+json")//add几个就增加几个        .post(RequestBody.create(MediaType.parse("text/x-markdown; charset=utf-8"), "postBody"))        //RequestBody内容可以很丰富，第二个参数可以是多种类型的字符集        .build();

RequestBody

需要MediaType

RequestBody requestBody = RequestBody.create(MediaType.parse("text/x-markdown; charset=utf-8"),body);

RequestBody requestBody = RequestBody.create(MediaType.parse("application/json; charset=utf-8"),json);

MediaType mediaType = MediaType.parse("image/png");

用法2：

RequestBody requestBody = new RequestBody() {
    @Override public MediaType contentType() {
        return MediaType.parse("text/x-markdown; charset=utf-8");;
    }

    @Override public void writeTo(BufferedSink sink) throws IOException {
        sink.writeUtf8("Numbers\n");
        sink.writeUtf8("-------\n");
        for (int i = 2; i <= 997; i++) {
            sink.writeUtf8(String.format(" * %s = %s\n", i, factor(i)));
        }
    }

    private String factor(int n) {
        for (int i = 2; i < n; i++) {
            int x = n / i;
            if (x * i == n) return factor(x) + " × " + i;
        }
        return Integer.toString(n);
    }
};

用法3：

RequestBody formBody = new FormBody.Builder()
        .add("search", "Jurassic Park")
        .addEncoded("encoded","utf-8")
        .build();

用法4：

RequestBody requestBody = new MultipartBody.Builder()
        .setType(MultipartBody.FORM)
        .addPart(Header,RequestBody)//添加包含头和body的Part
        .addFormDataPart("title", "Square Logo")//表单中添加表单
        .addFormDataPart("image", "logo-square.png",
                RequestBody.create(MEDIA_TYPE_PNG, new File("website/static/logo-square.png")))
        .build();

MediaType

配置请求类型

MediaType mediaType = MediaType.parse("text/x-markdown; charset=utf-8");

MediaType mediaType = MediaType.parse("image/png");

Response

用法1：

Response response = httpclient.newCall(request).execute();

用法2：

httpclient.newCall(request).enqueue(new Callback() {
    @Override
    public void onFailure(Call call, IOException e) {
        
    }

    @Override
    public void onResponse(Call call, Response response) throws IOException {

    }
});

ResponseBody responseBody = response.body();
response.body().string();
response.code();//HTTP status code
response.header("key1");
response.header("key2");
response.headers("key1");
response.networkResponse();

还有很多实用的方法。