解决：java.net.SocketException: Software caused connection abort: recv failed

前言：最近在学习 NIO 和netty 相关知识时，在bio的模式下，遇到了
java.net.SocketException: Software caused connection abort: recv failed 的问题，刚好解决了，记录一下
我是启动一个服务绑定8801端口，启动然 客户端使用 httpClient 进行发起一个get请求，如果成功请求后会输出 服务端的 "hello,nio1"的字样但时间情况报错了。

大概的意思就是 程序连接中止：接受失败，然后我就开始检查代码，用原生的http请求也是能正常返回的，浏览器，和crul http://localhost:8801也是正常返回，那我就感觉很奇怪，为什么借助httpClient就会失败呢？
网上查了下这个报错大概意思就直接意思： 客户端和服务端建立tcp的短连接,每次客户端发送一次请求, 服务端响应后关闭与客户端的连接. 如果客户端在服务端关闭连接后,没有释放连接,继续试图发送请求和接收响应. 这个时候就会出错.

于是我开始想，会不会是服务端关闭太快导致客户端正在读的时候，服务端已经关闭了，导致报错。果断在关闭的时候阻塞线程一秒试试Thread.sleep(1000)，就解决了。 所以这个问题报错的原因就是如上面红色字体描述的那样，在我这里就是服务端关闭太快了。

示例代码：

服务端代码

package org.geekbang.netty.server;

import java.io.IOException;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;

// 单线程的socket程序
public class HttpServer01 {
   public static void main(String[] args) throws IOException {
       // 开启8801端口
       ServerSocket serverSocket = new ServerSocket(8801);
       while (true) {
           try {
               Socket socket = serverSocket.accept();
               service(socket);
           } catch (IOException e) {
               e.printStackTrace();
           }
       }
   }

   private static void service(Socket socket) {
       try {
           PrintWriter printWriter = new PrintWriter(socket.getOutputStream(), true);
           printWriter.println("HTTP/1.1 200 OK");
           printWriter.println("Content-Type:text/html;charset=utf-8");
           printWriter.println("Connection: keep-alive");
           String body = "hello,nio1";
           // 一定要告诉他长度
           printWriter.println("Content-Length: " + body.getBytes().length);
           printWriter.println();
           printWriter.write(body);
           // 打开下面这行 Thread.sleep(1000) 代码，延迟主线程处理关闭流和soket 就解决了
           // Thread.sleep(1000);
           printWriter.close();
           socket.close();
       } catch (Exception e) {
           e.printStackTrace();
       }
   }
}

客户端代码：

package org.geekbang.netty.util;

import lombok.extern.slf4j.Slf4j;
import org.apache.http.HttpEntity;
import org.apache.http.NameValuePair;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.message.BasicNameValuePair;
import org.apache.http.util.EntityUtils;

import java.io.*;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.ArrayList;
import java.util.List;

/**
* @author lvzb31988
* @description: HttpClient 小试牛刀
* @date 2022/3/13
*/
@Slf4j
public class HttpClientHelper {
   public static CloseableHttpClient httpclient = HttpClients.createDefault();

   public static String getAsString(String url) throws IOException {
       HttpGet httpGet = new HttpGet(url);
       // jdk7增强try 这种写法是try-with-resources resources对象需要是 AutoCloseable接口的子类
       try (CloseableHttpResponse response = httpclient.execute(httpGet)) {
           System.out.println("see see what get this: " + response.getStatusLine());
           HttpEntity entity = response.getEntity();
           return EntityUtils.toString(entity, "UTF-8");
       }
   }

   public static String httpRequest(String requestUrl, String requestMethod, String outputStr) {
       StringBuffer buffer = null;
       try {
           URL url = new URL(requestUrl);
           HttpURLConnection conn = (HttpURLConnection) url.openConnection();
           conn.setDoOutput(true);
           conn.setDoInput(true);
           conn.setRequestMethod(requestMethod);
           conn.connect();
           //往服务器端写内容 也就是发起http请求需要带的参数
           if (null != outputStr) {
               OutputStream os = conn.getOutputStream();
               os.write(outputStr.getBytes("utf-8"));
               os.close();
           }

           //读取服务器端返回的内容
           InputStream is = conn.getInputStream();
           InputStreamReader isr = new InputStreamReader(is, "utf-8");
           BufferedReader br = new BufferedReader(isr);
           buffer = new StringBuffer();
           String line = null;
           while ((line = br.readLine()) != null) {
               buffer.append(line);
           }
       } catch (Exception e) {
           e.printStackTrace();
       }
       return buffer.toString();
   }


   public static void main(String[] args) throws IOException {

       String url = "http://www.baidu.com";
       String url1 = "http://localhost:8801";
       
       // 客户端请求 8801单线程服务：必定失败，然后会自动重新执行请求后面几次同样失败 ： Software caused connection abort: recv failed
       String resultString1 = HttpClientHelper.getAsString(url1);
       log.info("get调用8801返回结果:{}", resultString1);

//        String httpResult = HttpClientHelper.httpRequest(url, "GET", null);
//        log.info("原生 http get调用返回结果:{}", httpResult);
   }
}