笔记--解决Android使用retrofit2 OkHttp3短时间内大量通讯提示Socket Failed:EMFILE

Vaccae

发布于 2022-02-11 08:14:16

8890

发布于 2022-02-11 08:14:16

文章被收录于专栏：微卡智享

前言

Androidd在做Http请求，使用Retrofit2是一个比较方便的事，这个我一直也用了蛮久了，只不过最近在项目中突然遇到了问题，也是通过分析测试后解决，顺便做一下笔记。

事件回顾

报错图片

当时程序上是做盘点的业务流程，点击盘点的按钮时会同时有35个Http的请求，实际操作时是不停地地点击盘点，多次后出现的这个情况，具体的定位分析里这个操作除了Http请求返回数据后UI显示，基本没啥别的业务逻辑操作，所以问题也比较好定位，应该是同一时间多次请求Http造成的原因。

请求源码

package networking.retrofit;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.concurrent.TimeUnit;

import okhttp3.ConnectionPool;
import okhttp3.Cookie;
import okhttp3.CookieJar;
import okhttp3.HttpUrl;
import okhttp3.OkHttpClient;
import retrofit2.Retrofit;
import retrofit2.converter.gson.GsonConverterFactory;


/**
 * 获取Retrofit类用于Http通信
 */

public class retrofitAPIManager<T> {
    //基本URL地址
    public static String SERVER_URL = "url";
    //Cookies类型  0-每次注册时登记   1-按每次访问的URL登记
    public static int Cookiestype = 0;
    //Cookies类型如果为每次注册登记时用到检索关键前
    public static String Cookiecontains = "login";
    //Cookies类型如果为每次注册登记时用到Key
    public static String CookiesKey = "SumSoft";

    public T provideClientApi(Class<T> tClass) {
        Retrofit retrofit = new Retrofit.Builder()
                .baseUrl(SERVER_URL)
                .addConverterFactory(GsonConverterFactory.create())
                .client(genericClient())
                .build();
        return retrofit.create(tClass);
    }


    //获取OkHttpClient
    public static OkHttpClient genericClient() {
        OkHttpClient httpClient = new OkHttpClient.Builder()
                .cookieJar(new CookieJar() {
                    private final HashMap<String, List<Cookie>> cookieStore = new HashMap<>();

                    @Override
                    public void saveFromResponse(HttpUrl url, List<Cookie> cookies) {
                        //根据类型来判断存入的Cookies用于后面读取用
                        if (Cookiestype == 0) {
                            //判断url里面是注册的更新Key
                            if (url.toString().contains(Cookiecontains)) {
                                cookieStore.put(CookiesKey, cookies);
                            }
                        } else {
                            cookieStore.put(url.toString(), cookies);
                        }

                    }

                    @Override
                    public List<Cookie> loadForRequest(HttpUrl url) {
                        List<Cookie> cookies;
                        if (Cookiestype == 0) {
                            cookies = cookieStore.get(CookiesKey);
                        } else {
                            cookies = cookieStore.get(url.toString());
                        }
                        return cookies != null ? cookies : new ArrayList<Cookie>();
                    }
                })
                .build();

        return httpClient;
    }
}

其实这个封装好的源码一直用了很久了，都正常使用，一直使用的Retrofit2+OkHttp3进行网络请求，所以没再深入研究，既然出现问题了，那就研究下有没有相关遇到这个问题的，网上搜了下资料：

从OkHttp的Github源码是可以看到，上面说了，同一台设备在短时间内发起了200次http的请求，就会报这个错误了。

那我们就从OkHttp中来看看分析下，上面代码中使用genericClient创建的OkHttp，用到了new OkHttpClient.Builder()，那我们就分析下这里怎么处理的，OkHttpClient的ConnectionPool网络请求的线程池，在OkHttpClient源码中：

OkHttpClient.java中


    /**
     * Sets the connection pool used to recycle HTTP and HTTPS connections.
     *
     * <p>If unset, a new connection pool will be used.
     */
    public Builder connectionPool(ConnectionPool connectionPool) {
      if (connectionPool == null) throw new NullPointerException("connectionPool == null");
      this.connectionPool = connectionPool;
      return this;
    }

上面可以看到创建的连接线程池，那我们再找这个ConnectionPool。

ConnectionPool.java

  /**
   * Create a new connection pool with tuning parameters appropriate for a single-user application.
   * The tuning parameters in this pool are subject to change in future OkHttp releases. Currently
   * this pool holds up to 5 idle connections which will be evicted after 5 minutes of inactivity.
   */
  public ConnectionPool() {
    this(5, 5, TimeUnit.MINUTES);
  }

  public ConnectionPool(int maxIdleConnections, long keepAliveDuration, TimeUnit timeUnit) {
    this.maxIdleConnections = maxIdleConnections;
    this.keepAliveDurationNs = timeUnit.toNanos(keepAliveDuration);

    // Put a floor on the keep alive duration, otherwise cleanup will spin loop.
    if (keepAliveDuration <= 0) {
      throw new IllegalArgumentException("keepAliveDuration <= 0: " + keepAliveDuration);
    }
  }

ConnectionPool中的构造方法里默认最大线程空闲数是5，keepAlive时间为5分钟。也就是发起一次网络连接后，5分钟内不会断开连接。

这样像刚才我们多次点击盘点的时，短时间内链接不会断开，很快就直接200个了，所以问题应该就出在这里，修改了ConnectPool的连接参数就可以解决这个问题。

解决方法

在创建OkHttpClient.Builder中加入ConnectPool的设置。所以在原来的创建代码中加入了connectPool设置其连接时间，保活时间，我这里设置了500毫秒的时间，如下图：

   //获取OkHttpClient
    public static OkHttpClient genericClient() {
        OkHttpClient httpClient = new OkHttpClient.Builder()
                .cookieJar(new CookieJar() {
                    private final HashMap<String, List<Cookie>> cookieStore = new HashMap<>();

                    @Override
                    public void saveFromResponse(HttpUrl url, List<Cookie> cookies) {
                        //根据类型来判断存入的Cookies用于后面读取用
                        if (Cookiestype == 0) {
                            //判断url里面是注册的更新Key
                            if (url.toString().contains(Cookiecontains)) {
                                cookieStore.put(CookiesKey, cookies);
                            }
                        } else {
                            cookieStore.put(url.toString(), cookies);
                        }

                    }

                    @Override
                    public List<Cookie> loadForRequest(HttpUrl url) {
                        List<Cookie> cookies;
                        if (Cookiestype == 0) {
                            cookies = cookieStore.get(CookiesKey);
                        } else {
                            cookies = cookieStore.get(url.toString());
                        }
                        return cookies != null ? cookies : new ArrayList<Cookie>();
                    }
                })
                //设置okhttp连接池保活时间，源码中默认是5分钟，这里改为500毫秒。
                .connectionPool(new ConnectionPool(5,
                        500, TimeUnit.MILLISECONDS))
                .build();

        return httpClient;
    }

完整代码

package networking.retrofit;


import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.concurrent.TimeUnit;

import okhttp3.ConnectionPool;
import okhttp3.Cookie;
import okhttp3.CookieJar;
import okhttp3.HttpUrl;
import okhttp3.OkHttpClient;
import retrofit2.Retrofit;
import retrofit2.converter.gson.GsonConverterFactory;


/**
 * Created by Administrator on 2016-12-06.
 * 获取Retrofit类用于Http通信
 */

public class retrofitAPIManager<T> {
    //基本URL地址
    public static String SERVER_URL = "url";
    //Cookies类型  0-每次注册时登记   1-按每次访问的URL登记
    public static int Cookiestype = 0;
    //Cookies类型如果为每次注册登记时用到检索关键前
    public static String Cookiecontains = "login";
    //Cookies类型如果为每次注册登记时用到Key
    public static String CookiesKey = "SumSoft";

    public T provideClientApi(Class<T> tClass) {
        Retrofit retrofit = new Retrofit.Builder()
                .baseUrl(SERVER_URL)
                .addConverterFactory(GsonConverterFactory.create())
                .client(genericClient())
                .build();
        return retrofit.create(tClass);
    }


    //获取OkHttpClient
    public static OkHttpClient genericClient() {
        OkHttpClient httpClient = new OkHttpClient.Builder()
                .cookieJar(new CookieJar() {
                    private final HashMap<String, List<Cookie>> cookieStore = new HashMap<>();

                    @Override
                    public void saveFromResponse(HttpUrl url, List<Cookie> cookies) {
                        //根据类型来判断存入的Cookies用于后面读取用
                        if (Cookiestype == 0) {
                            //判断url里面是注册的更新Key
                            if (url.toString().contains(Cookiecontains)) {
                                cookieStore.put(CookiesKey, cookies);
                            }
                        } else {
                            cookieStore.put(url.toString(), cookies);
                        }

                    }

                    @Override
                    public List<Cookie> loadForRequest(HttpUrl url) {
                        List<Cookie> cookies;
                        if (Cookiestype == 0) {
                            cookies = cookieStore.get(CookiesKey);
                        } else {
                            cookies = cookieStore.get(url.toString());
                        }
                        return cookies != null ? cookies : new ArrayList<Cookie>();
                    }
                })
                //设置okhttp连接池保活时间，源码中默认是5分钟，这里改为500毫秒。
                .connectionPool(new ConnectionPool(5,
                        500, TimeUnit.MILLISECONDS))
                .build();

        return httpClient;
    }
}

完

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原始发表：2022-01-17，如有侵权请联系 cloudcommunity@tencent.com 删除

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