概述

OKHttp 是一个当前主流的网络请求的开源框架，由 Square 公司开发，用于替代 HttpUrlConnection 和 Apache HttpClient

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

功能

• PUT，DELETE，POST，GET 等请求
• 文件的上传下载
• 加载图片 (内部会图片大小自动压缩)
• 支持请求回调，直接返回对象、对象集合
• 支持 Session 的保持

依赖

<dependency>
    <groupId>com.squareup.okhttp3</groupId>
    <artifactId>okhttp</artifactId>
    <version>4.0.1</version>
</dependency>

测试请求

GET

测试 Get 请求

@Test
public void testGet() {
    String url = "https://www.baidu.com";
    OkHttpClient client = new OkHttpClient();
    Request request = new Request.Builder()
        .url(url)
        .build();
    Call call = client.newCall(request);
    try {
        Response response = call.execute();
        System.out.println(response.body().string());
    } catch (IOException e) {
        e.printStackTrace();
    }
}

POST

测试 POST 请求

@Test
public void testPost() {
    String url = "http://localhost:9001/oauth/token";
    OkHttpClient client = new OkHttpClient();
    RequestBody body = new FormBody.Builder()
        .add("username", "admin")
        .add("password", "123456")
        .add("grant_type", "password")
        .add("client_id", "client")
        .add("client_secret", "secret")
        .build();
    Request request = new Request.Builder()
        .url(url)
        .post(body)
        .build();
    Call call = client.newCall(request);
    try {
        Response response = call.execute();
        System.out.println(response.body().string());
    } catch (IOException e) {
        e.printStackTrace();
    }
}

工具类

OKHttp

为了简化我们的构建过程，可以封装如下工具类

package com.funtl.myshop.plus.commons.utils;

import okhttp3.Call;
import okhttp3.Callback;
import okhttp3.MediaType;
import okhttp3.OkHttpClient;
import okhttp3.Request;
import okhttp3.RequestBody;
import okhttp3.Response;

import java.io.IOException;
import java.util.Iterator;
import java.util.Map;
import java.util.concurrent.TimeUnit;

/**
 * OKHttp3
 * <p>
 * Description:
 * </p>
 *
 * @author Lusifer
 * @version v1.0.0
 * @date 2019-07-29 14:05:08
 * @see com.funtl.myshop.plus.commons.utils
 */
public class OkHttpClientUtil {
    private static final int READ_TIMEOUT = 100;
    private static final int CONNECT_TIMEOUT = 60;
    private static final int WRITE_TIMEOUT = 60;
    private static final MediaType JSON = MediaType.parse("application/json; charset=utf-8");
    private static final byte[] LOCKER = new byte[0];
    private static OkHttpClientUtil mInstance;
    private OkHttpClient okHttpClient;

    private OkHttpClientUtil() {
        okhttp3.OkHttpClient.Builder clientBuilder = new okhttp3.OkHttpClient.Builder();
        // 读取超时
        clientBuilder.readTimeout(READ_TIMEOUT, TimeUnit.SECONDS);
        // 连接超时
        clientBuilder.connectTimeout(CONNECT_TIMEOUT, TimeUnit.SECONDS);
        //写入超时
        clientBuilder.writeTimeout(WRITE_TIMEOUT, TimeUnit.SECONDS);
        okHttpClient = clientBuilder.build();
    }

    /**
     * 单例模式获取 NetUtils
     *
     * @return {@link OkHttpClientUtil}
     */
    public static OkHttpClientUtil getInstance() {
        if (mInstance == null) {
            synchronized (LOCKER) {
                if (mInstance == null) {
                    mInstance = new OkHttpClientUtil();
                }
            }
        }
        return mInstance;
    }

    /**
     * GET，同步方式，获取网络数据
     *
     * @param url 请求地址
     * @return {@link Response}
     */
    public Response getData(String url) {
        // 构造 Request
        Request.Builder builder = new Request.Builder();
        Request request = builder.get().url(url).build();
        // 将 Request 封装为 Call
        Call call = okHttpClient.newCall(request);
        // 执行 Call，得到 Response
        Response response = null;
        try {
            response = call.execute();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return response;
    }

    /**
     * POST 请求，同步方式，提交数据
     *
     * @param url        请求地址
     * @param bodyParams 请求参数
     * @return {@link Response}
     */
    public Response postData(String url, Map<String, String> bodyParams) {
        // 构造 RequestBody
        RequestBody body = setRequestBody(bodyParams);
        // 构造 Request
        Request.Builder requestBuilder = new Request.Builder();
        Request request = requestBuilder.post(body).url(url).build();
        // 将 Request 封装为 Call
        Call call = okHttpClient.newCall(request);
        // 执行 Call，得到 Response
        Response response = null;
        try {
            response = call.execute();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return response;
    }

    /**
     * GET 请求，异步方式，获取网络数据
     *
     * @param url       请求地址
     * @param myNetCall 回调函数
     */
    public void getDataAsync(String url, final MyNetCall myNetCall) {
        // 构造 Request
        Request.Builder builder = new Request.Builder();
        Request request = builder.get().url(url).build();
        // 将 Request 封装为 Call
        Call call = okHttpClient.newCall(request);
        // 执行 Call
        call.enqueue(new Callback() {
            @Override
            public void onFailure(Call call, IOException e) {
                myNetCall.failed(call, e);
            }

            @Override
            public void onResponse(Call call, Response response) throws IOException {
                myNetCall.success(call, response);
            }
        });
    }

    /**
     * POST 请求，异步方式，提交数据
     *
     * @param url        请求地址
     * @param bodyParams 请求参数
     * @param myNetCall  回调函数
     */
    public void postDataAsync(String url, Map<String, String> bodyParams, final MyNetCall myNetCall) {
        // 构造 RequestBody
        RequestBody body = setRequestBody(bodyParams);
        // 构造 Request
        buildRequest(url, myNetCall, body);
    }

    /**
     * 同步 POST 请求，使用 JSON 格式作为参数
     *
     * @param url  请求地址
     * @param json JSON 格式参数
     * @return 响应结果
     * @throws IOException 异常
     */
    public String postJson(String url, String json) throws IOException {
        RequestBody body = RequestBody.create(JSON, json);
        Request request = new Request.Builder()
                .url(url)
                .post(body)
                .build();
        Response response = okHttpClient.newCall(request).execute();
        if (response.isSuccessful()) {
            return response.body().string();
        } else {
            throw new IOException("Unexpected code " + response);
        }
    }

    /**
     * 异步 POST 请求，使用 JSON 格式作为参数
     *
     * @param url       请求地址
     * @param json      JSON 格式参数
     * @param myNetCall 回调函数
     * @throws IOException 异常
     */
    public void postJsonAsync(String url, String json, final MyNetCall myNetCall) throws IOException {
        RequestBody body = RequestBody.create(JSON, json);
        // 构造 Request
        buildRequest(url, myNetCall, body);
    }

    /**
     * 构造 POST 请求参数
     *
     * @param bodyParams 请求参数
     * @return {@link RequestBody}
     */
    private RequestBody setRequestBody(Map<String, String> bodyParams) {
        RequestBody body = null;
        okhttp3.FormBody.Builder formEncodingBuilder = new okhttp3.FormBody.Builder();
        if (bodyParams != null) {
            Iterator<String> iterator = bodyParams.keySet().iterator();
            String key = "";
            while (iterator.hasNext()) {
                key = iterator.next().toString();
                formEncodingBuilder.add(key, bodyParams.get(key));
            }
        }
        body = formEncodingBuilder.build();
        return body;
    }

    /**
     * 构造 Request 发起异步请求
     *
     * @param url       请求地址
     * @param myNetCall 回调函数
     * @param body      {@link RequestBody}
     */
    private void buildRequest(String url, MyNetCall myNetCall, RequestBody body) {
        Request.Builder requestBuilder = new Request.Builder();
        Request request = requestBuilder.post(body).url(url).build();
        // 将 Request 封装为 Call
        Call call = okHttpClient.newCall(request);
        // 执行 Call
        call.enqueue(new Callback() {
            @Override
            public void onFailure(Call call, IOException e) {
                myNetCall.failed(call, e);
            }

            @Override
            public void onResponse(Call call, Response response) throws IOException {
                myNetCall.success(call, response);
            }
        });
    }

    /**
     * 自定义网络回调接口
     */
    public interface MyNetCall {
        /**
         * 请求成功的回调处理
         *
         * @param call     {@link Call}
         * @param response {@link Response}
         * @throws IOException 异常
         */
        void success(Call call, Response response) throws IOException;

        /**
         * 请求失败的回调处理
         *
         * @param call {@link Call}
         * @param e    异常
         */
        void failed(Call call, IOException e);
    }

}