Question

我遇到Socket接受失败的问题，我使用RESTFul技术开发了一个应用程序，它涉及服务器端和客户端代码。

服务器端我维护文本文件以存储0,1,2,3,4 ...

等状态

客户端使用URL向服务器提供RESTFul请求，服务器根据该请求读取该文本文件和响应。我有很多客户端（超过300个）来访问此请求。所有客户都可以同时询问请求。

错误：

14 Jun, 2014 8:24:12 PM org.apache.tomcat.util.net.JIoEndpoint$Acceptor run
SEVERE: Socket accept failed
    java.net.SocketException: Too many open files
    at java.net.PlainSocketImpl.socketAccept(Native Method)
    at java.net.PlainSocketImpl.accept(PlainSocketImpl.java:408)
    at java.net.ServerSocket.implAccept(ServerSocket.java:462)
    at java.net.ServerSocket.accept(ServerSocket.java:430)
    at org.apache.tomcat.util.net.DefaultServerSocketFactory.acceptSocket
          (DefaultServerSocketFactory.java:60)
    at org.apache.tomcat.util.net.JIoEndpoint$Acceptor.run(JIoEndpoint.java:216)
    at java.lang.Thread.run(Thread.java:662)

用于检查服务器URL是否可访问的代码：

public boolean isInternetReachable() {      
    try {          
        URL url = new URL("http://myhost.com/myapp/");
        httpcon = (HttpURLConnection) url.openConnection();
        httpcon.addRequestProperty("User-Agent", "Mozilla/4.76");
        return true;            
    } catch (IOException ex) {
         return false;
    }/*finally{
        if(httpcon!=null)httpcon.disconnect();
    }*/
}

检查内容有效：

public  boolean isContentActive() {
    BufferedReader in  =null;
    try {          
        URL url = new URL("http://myhost.com/myapp/status.txt");
        httpcon = (HttpURLConnection) url.openConnection();
        httpcon.addRequestProperty("User-Agent", "Mozilla/4.76");
        in = new BufferedReader(new InputStreamReader(httpcon.getInputStream()));
        return true;
    } catch (Exception ex) {
        return false;
    }finally{
         if(in!=null){
            try {
                in.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
         }
         //if(httpcon!=null)httpcon.disconnect();
     }
}

阅读文本文件：

public String readTxtForJson() 
throws IOException{
    String versionRead="";
    boolean reachableflag=isInternetReachable();
  if(reachableflag){
    boolean flag=isContentActive();
    BufferedReader in=null;
    if(flag){
      URL url = new URL("http://myhost.com/myapp/status.txt");
      try{
        httpcon = (HttpURLConnection) url.openConnection();
        httpcon.addRequestProperty("User-Agent", "Mozilla/4.76");
        in = new BufferedReader(new InputStreamReader(httpcon.getInputStream()));
        versionRead = in.readLine();                
      }catch(Exception e){
        System.out.println("Error : In access workshop URL");
        e.printStackTrace();                    
      }finally{
         if(in!=null)in.close();
         //if(httpcon!=null)httpcon.disconnect();
      }
      return versionRead;               
    }else{
          versionRead="11"; // 11 stands for No live content
          return versionRead;
        }
  }else{            
       versionRead="12"; //12 stands for Network Not Reachable
       return versionRead;
  }     
}

我所尝试的答案仍然是我得到的错误......

我正确维护数据库连接，上面的代码是否有任何泄漏？

Answer 1

您需要确保在所有情况下都执行in.close（）。它应该在最后的块中。

使用disconnect（）的建议会适得其反，因为它会禁用HTTP keep-alive并且会产生更多连接。

Answer 2

请现在看下面

String curl = "http://www.tempsite.com/status/status.txt";
HttpURLConnection httpcon=null;
public String getstatus()
{
    String versionRead="";
    URL url = new URL(curl);
    try{
            if(httpcon==null) 
            {
              httpcon= (HttpURLConnection) url.openConnection();
            }
            httpcon.addRequestProperty("User-Agent", "Mozilla/4.76");

            if(httpcon.getResponseCode()==HTTP_OK)
            {
              BufferedReader in = new BufferedReader(new InputStreamReader(httpcon.getInputStream()));
              versionRead = in.readLine();
              in.close();
            }
    }
    catch(Exception e)
    {
                System.out.println("Stream may not Closed");
    }
    return versionRead;
}

SocketException：打开文件太多经过服务器启动一段时间后

2 个答案: