非阻塞write()无限大-java
我有一个简单的网页抓取。而OP_WRITE会一直触发选择器,因此select()永远不会结束。Select始终返回1,尽管频道已完成其工作并已关闭,但仍在等待写入。我怎么处理?我的CPU也非常高 代码如下:非阻塞write()无限大-java,java,network-programming,Java,Network Programming,我有一个简单的网页抓取。而OP_WRITE会一直触发选择器,因此select()永远不会结束。Select始终返回1,尽管频道已完成其工作并已关闭,但仍在等待写入。我怎么处理?我的CPU也非常高 代码如下: public static void main(String [] args) { try { String adder=""; Selector selector= simpleFetcher.selector; selector = Selector.open
public static void main(String [] args)
{
try
{
String adder="";
Selector selector= simpleFetcher.selector;
selector = Selector.open();
Charset charset = Charset.forName("ISO-8859-1");
try{
//add to selector the host and settings
addHost(selector, "localhost", 80);
addHost(selector, "site.org", 80);
} catch (UnresolvedAddressException ex) {System.out.println("Address Not exist "+ex.getMessage());}
while(true)
{
int selectedn = selector.select(2000);
if (selectedn==0)
{
Set<SelectionKey> SelectorKeys = selector.keys();
Iterator<SelectionKey> iterator = SelectorKeys.iterator();
while(iterator.hasNext())
{
SelectionKey k = (SelectionKey) iterator.next();
SocketChannel channel = (SocketChannel) k.channel();
String rHost;
InetAddress addr = channel.socket().getInetAddress();
rHost= addr.getHostAddress();
System.out.println(rHost+" is timeout");
}
System.out.println("adder:"+adder);
selector.close();
System.out.println("No more keys.. Exiting");
return;
}
Set<SelectionKey> selectedKeys = selector.selectedKeys();
Iterator<SelectionKey> iterator = selectedKeys.iterator();
while(iterator.hasNext())
{
SelectionKey key = (SelectionKey) iterator.next();
iterator.remove();
if (key.isValid()==false) {System.out.println("key not valid"); continue;}
try{
if (key.isConnectable())
{
System.out.println("Will connect right now");
SocketChannel channel = (SocketChannel) key.channel();
if (!channel.finishConnect()) { System.out.println("Not finished connection. continue.."); continue; }
if (channel.isConnectionPending()==false && channel.socket().isClosed()==true) System.out.println("CLOSED?");
SelectionKey k = channel.register(key.selector(),SelectionKey.OP_READ);
SelectionKey k2 = channel.register(key.selector(),SelectionKey.OP_WRITE);
//SelectionKey k = channel.register(key.selector(),SelectionKey.OP_READ | SelectionKey.OP_WRITE);
k.attach(ByteBuffer.allocate(4000));
System.out.println("Just Connected");
continue;
}
if (key.isReadable())
{
int readB;
System.out.println("Ready for reading..");
SocketChannel channel = (SocketChannel) key.channel();
ByteBuffer buffer = (ByteBuffer) key.attachment();
CharBuffer charbuffer = buffer.asCharBuffer();
if ((readB=channel.read(buffer)) !=-1)
{
System.out.println("Key accepted - reading..");
int current_capacity=buffer.position();
buffer.flip();
CharBuffer c = charset.decode(buffer);
char[] arr = c.array();
String data = new String(arr);
String[] lines = data.split("\\r\\n\\r\\n");
if (lines.length>1)
{
String header = lines[0];
String rest_body = lines[1];
//System.out.println("Header is: "+header);
//System.out.println("Body is: "+rest_body);
adder+=header+rest_body;
}
else { adder+=new String(arr); }
}
else
{
key.channel().close();
key.cancel();
System.out.println("Key cancled");
System.out.println(adder);
continue;
}
if (readB==0) System.out.println("The READ RETURNS 0");
System.out.println();
buffer.clear();
continue;
}
if (key.isWritable())
{
//System.out.println("Ready to write");
SocketChannel channel = (SocketChannel) key.channel();
String rHost;
Socket s = channel.socket();
s.shutdownOutput();
InetAddress addr = channel.socket().getInetAddress();
rHost= addr.getHostAddress();
//System.out.println(rHost);
if (s.isOutputShutdown()) continue;
String bytestowrite="GET / HTTP/1.1\r\nHost: "+rHost+"\r\nUser-agent: Agent 1.0 Experimental\r\nAccept: */*\r\nAccept-Language: en-US,en;q=0.5\r\nConnection: keep-alive\r\n\r\n";
ByteBuffer buffer = ByteBuffer.wrap(bytestowrite.getBytes());
while(buffer.hasRemaining()) channel.write(buffer);
key.cancel();
continue;
}
} catch (IOException ex) {
System.out.println("EXCEPTION: "+ex.getMessage());
key.cancel();
try { key.channel().close();}
catch (IOException cex) {};
}
System.out.println("End of iterator loop");
}
}
}catch (IOException ex) {System.out.println("Timeout");}
}
publicstaticvoidmain(字符串[]args)
{
尝试
{
字符串加法器=”;
选择器选择器=simpleFetcher.Selector;
选择器=selector.open();
Charset Charset=Charset.forName(“ISO-8859-1”);
试一试{
//将选择器添加到主机和设置
addHost(选择器,“localhost”,80);
addHost(选择器,“site.org”,80);
}catch(unsolvedAddressException ex){System.out.println(“地址不存在”+ex.getMessage());}
while(true)
{
int selectedn=选择器。选择(2000);
如果(selectedn==0)
{
设置SelectorKeys=selector.keys();
迭代器迭代器=SelectorKeys.Iterator();
while(iterator.hasNext())
{
SelectionKey k=(SelectionKey)迭代器.next();
SocketChannel=(SocketChannel)k.channel();
弦菱形;
InetAddress addr=channel.socket().getInetAddress();
rHost=addr.getHostAddress();
System.out.println(rHost+“是超时”);
}
System.out.println(“加法器:“+加法器”);
selector.close();
System.out.println(“不再有键..退出”);
返回;
}
设置selectedKeys=选择器。selectedKeys();
迭代器迭代器=selectedKeys.Iterator();
while(iterator.hasNext())
{
SelectionKey=(SelectionKey)迭代器.next();
iterator.remove();
如果(key.isValid()==false){System.out.println(“key无效”);继续;}
试一试{
if(key.isConnectable())
{
System.out.println(“将立即连接”);
SocketChannel=(SocketChannel)key.channel();
如果(!channel.finishConnect()){System.out.println(“未完成连接。继续”);continue;}
if(channel.isConnectionPending()==false&&channel.socket().isClosed()==true)System.out.println(“CLOSED?”);
SelectionKey k=通道寄存器(key.selector(),SelectionKey.OP_READ);
SelectionKey k2=channel.register(key.selector(),SelectionKey.OP_WRITE);
//SelectionKey k=通道.寄存器(key.selector(),SelectionKey.OP_READ | SelectionKey.OP_WRITE);
k、 附加(ByteBuffer.allocate(4000));
System.out.println(“刚刚连接”);
继续;
}
if(key.isReadable())
{
int readB;
System.out.println(“准备好读取…”);
SocketChannel=(SocketChannel)key.channel();
ByteBuffer缓冲区=(ByteBuffer)键。附件();
CharBuffer CharBuffer=buffer.asCharBuffer();
if((readB=channel.read(buffer))!=-1)
{
System.out.println(“接受的键-读取…”);
int current_capacity=buffer.position();
flip();
CharBuffer c=字符集解码(buffer);
char[]arr=c.array();
字符串数据=新字符串(arr);
String[]line=data.split(\\r\\n\\r\\n”);
如果(线条长度>1)
{
字符串头=行[0];
字符串rest_body=行[1];
//System.out.println(“表头为:“+表头”);
//System.out.println(“主体为:“+rest\u主体”);
加法器+=头+剩余体;
}
else{adder+=新字符串(arr);}
}
其他的
{
key.channel().close();
键。取消();
System.out.println(“密钥取消”);
系统输出打印LN(加法器);
继续;
}
如果(readB==0)System.out.println(“读取返回0”);
System.out.println();
buffer.clear();
继续;
}
if(key.isWritable())
{
//System.out.println(“准备写入”);
SocketChannel=(SocketChannel)key.channel();
弦菱形;
sockets=channel.Socket();
s、 关机输出();
InetAddress addr=channel.socket().getInetAddress();
rHost=addr.getHostAddress();
//系统输出打印LN(rHost);
如果(s.isOutputShutdown())继续;
String bytestowrite=“GET/HTTP/1.1\r\nHost:“+rHost+”\r\n用户代理:代理1.0实验性\r\n概念:*/*\r\n概念语言:en-US,en;q=0.5\r\n连接:保持活动\r\n\r\n”;
ByteBuffer buffer=ByteBuffer.wrap(bytestowrite.getBytes());
while(buffer.haslaining())channel.write(buffer);
键。取消();
继续;
}
}捕获(IOEX异常){
System.out.println(“异常:+ex.getMessage());
键。取消();
请尝试{key.channel().close();}
捕获(iocex){};
}
System.out.println(“迭代器循环结束”);
}
}
}catch(IOException ex){System.out.println(“超时”);}
}
套接字通道几乎总是可写的,这意味着套接字发送缓冲区中几乎总是有可用空间。只有当发送方超过接收方时,这才不再是真的
因此,为OP_WRITE
注册通道是不正确的,除非它们已经经历了缓冲区满的情况