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  • Java相关问题整理

    1. OkHttpClient调用出现大量CLOSE_WAIT。

    问题定位:

      凡是系统中出现大量的CLOSE_WAIT,说明你的代码写的有问题,即:没有关闭连接。

    在OkHttpClient中,默认时 HTTP头字段 Connection 设置值为keep-alive,这样会导致服务端断开连接时,客户端不能及时的断开连接,从而出现大量的CLOSE_WAIT。

    问题修改:

      把HTTP头字段 Connection 设置值为close

    如下是一段短连接http调用代码。

    package com.xman.httpclient;
    
    import okhttp3.*;
    import org.springframework.stereotype.Service;
    
    import java.io.IOException;
    import java.util.concurrent.TimeUnit;
    
    /**
     * Created by wangyaofu on 2018/4/25.
     */
    @Service
    public class HttpServiceImpl {
    
        public final static int CONNECT_TIMEOUT =10000;
        public final static int READ_TIMEOUT=10000;
        public final static int WRITE_TIMEOUT=10000;
    
        public String httpGet(String url, String userAgent) {
                final Request request = new Request.Builder()
                        .url(url).header("User-Agent", userAgent).header("Connection", "close")
                        .build();
                OkHttpClient okHttpClient = new OkHttpClient.Builder()
                        .readTimeout(READ_TIMEOUT, TimeUnit.MILLISECONDS)
                        .writeTimeout(WRITE_TIMEOUT, TimeUnit.MILLISECONDS)
                        .connectTimeout(CONNECT_TIMEOUT, TimeUnit.MILLISECONDS)
                        .build();
            Response response;
            try {
                response = okHttpClient.newCall(request).execute();
                return response.body().string();
            } catch (Exception e) {
                //logger.error("httpGet err=" + e.getMessage());
            }
            return null;
        }
    
        public String httpPost(String url, String body) {
            RequestBody requestBody = RequestBody.create(MediaType.parse("application/json; charset=utf-8"), body);
            //创建一个请求对象
            Request request = new Request.Builder()
                    .url(url).header("Connection", "close")
                    .post(requestBody)
                    .build();
            //发送请求获取响应
            try {
                OkHttpClient okHttpClient = new OkHttpClient.Builder()
                        .readTimeout(READ_TIMEOUT, TimeUnit.MILLISECONDS)
                        .writeTimeout(WRITE_TIMEOUT, TimeUnit.MILLISECONDS)
                        .connectTimeout(CONNECT_TIMEOUT, TimeUnit.MILLISECONDS)
                        .build();
                Response response=okHttpClient.newCall(request).execute();
                if (response != null && response.body() != null) {
                    return response.body().string();
                }
            } catch (Exception e) {
                //logger.error("httpPost err=" + e.getMessage());
            }
            return null;
        }
    }
    

      

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  • 原文地址:https://www.cnblogs.com/voipman/p/10195164.html
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