转自 http://hi.baidu.com/xulin_1027/item/ef760d368f9470f72784f4f2
HttpClient(too many open files)
错误信息:
java.net.SocketException: Too many open files
at java.net.Socket.createImpl(Unknown Source)
at java.net.Socket.connect(Unknown Source)
at org.apache.http.conn.scheme.PlainSocketFactory.connectSocket(PlainSocketFactory.java:123)
严重: Endpoint ServerSocket[addr=0.0.0.0/0.0.0.0,port=0,localport=80] ignored exception: java.net.SocketException: Too many open files
java.net.SocketException: Too many open files
at java.net.PlainSocketImpl.socketAccept(Native Method)
网络中查询有说是linux的文件打开数超过了默认的1024个文件,具体查看linux下面的文件打开最大值的命令ulimit -a,出现信息如下:
core file size (blocks, -c) 0
data seg size (kbytes, -d) unlimited
scheduling priority (-e) 0
file size (blocks, -f) unlimited
pending signals (-i) 69631
max locked memory (kbytes, -l) 32
max memory size (kbytes, -m) unlimited
open files (-n) 1024
pipe size (512 bytes, -p) 8
POSIX message queues (bytes, -q) 819200
real-time priority (-r) 0
stack size (kbytes, -s) 10240
cpu time (seconds, -t) unlimited
max user processes (-u) 69631
virtual memory (kbytes, -v) unlimited
file locks (-x) unlimited
其中open files (-n) 1024 默认为1024,网络中有说解决方法是加大文件打开的最大值,ulimit -n 8192,此命令未测试;
但是由于Httpclient引起的。当并发访问量过大的时候,这个方法只是治标不治本的。所有还是解决Httpclient远程请求所造成Socket没有释放,HttpClient本身存在这个问题。
网络中解决方案如下(加上红色的两行代码):
client = new HttpClient();
client.getParams().setBooleanParameter("http.protocol.expect-continue", false);
HttpMethod httpMethod = ...;
httpMethod.addRequestHeader("Connection", "close");
client.executeMethod(httpMethod);
用unlimit放大操作系统最大打开文件数的确可以短时间解决 Too many open files的现象,但这不是本质原因。
本质原因肯定能够是你的程序中没有及时close掉文件(在linux/unix中Socket也是文件)。否则只有在上千的绝对同时并发时,才可能出现Too many open files错误。
HttpClient(too many open files) 解决办法
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转载自lizhe-0428.iteye.com/blog/1600018
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