Java SocketTimeoutException:读取超时
这是一个简单的基于客户端/服务器的乒乓球程序。 不幸的是,它无法工作并显示以下错误消息:Java SocketTimeoutException:读取超时,java,sockets,networking,socket-timeout-exception,Java,Sockets,Networking,Socket Timeout Exception,这是一个简单的基于客户端/服务器的乒乓球程序。 不幸的是,它无法工作并显示以下错误消息: java.net.SocketTimeoutException: Read timed out at java.net.SocketInputStream.socketRead0(Native Method) at java.net.SocketInputStream.read(Unknown Source) at java.net.SocketInputStream.read(Un
java.net.SocketTimeoutException: Read timed out
at java.net.SocketInputStream.socketRead0(Native Method)
at java.net.SocketInputStream.read(Unknown Source)
at java.net.SocketInputStream.read(Unknown Source)
at sun.nio.cs.StreamDecoder.readBytes(Unknown Source)
at sun.nio.cs.StreamDecoder.implRead(Unknown Source)
at sun.nio.cs.StreamDecoder.read(Unknown Source)
at java.io.InputStreamReader.read(Unknown Source)
它停在客户机任务30行,实际上客户机不读取服务器发送的内容。
代码如下:
服务器
包服务器客户端;
导入java.net。*;
导入java.io.*;
导入java.util.concurrent.*;
公共类服务器{
公共静态void main(字符串[]args){
ExecutorService esp=Executors.newFixedThreadPool(50);
try(ServerSocket ss=newserversocket(1027)){
while(true){
试一试{
套接字s=ss.accept();
可调用任务=新服务器任务;
特别是提交(任务);
}
catch(bindbe){}
捕获(连接异常){}
catch(noroutetohestexception nrthe){}
catch(IOException ioe){ioe.printStackTrace();}
}
}
catch(异常e){e.printStackTrace();}
}
}
服务器任务
包服务器客户端;
导入java.util.concurrent.*;
导入java.net。*;
导入java.io.*;
公共类ServerTask实现可调用{
插座;
服务器任务(套接字){
这个.s=s;
}
公开作废通知(){
BufferedWriter=null;
BufferedReader reader=null;
试一试{
reader=new BufferedReader(new InputStreamReader(s.getInputStream());
writer=newbufferedwriter(newoutputstreamwriter(s.getOutputStream());
int i=0;
StringBuilder sb=新的StringBuilder();
而((i=reader.read())!=-1){
某人附加((字符)i);
}
System.out.println(“客户端发送:“+sb”);
作家。写(“乒乓球”);
writer.flush();
}
catch(IOException ioe){ioe.printStackTrace();}
最后{
试一试{
writer.close();
}
catch(IOException ioe){ioe.printStackTrace();}
if(读卡器!=null){
试一试{
reader.close();
}
catch(IOException ioe){ioe.printStackTrace();}
}
试一试{
s、 close();
}
catch(IOException ioe){ioe.printStackTrace();}
}
返回null;
}
}
客户
包服务器客户端;
导入java.io.IOException;
导入java.net。*;
导入java.util.concurrent.*;
公共类客户端{
公共静态void main(字符串[]args){
ExecutorService es=Executors.newSingleThreadExecutor();
试一试{
套接字s=新套接字(InetAddress.getLocalHost(),1027);
试一试{
s、 设置超时(50000);
}
catch(SocketException se){se.printStackTrace();}
可调用任务=新客户端任务;
提交(任务);
}
catch(UnknownHostException uhe){uhe.printStackTrace();}
catch(IOException ioe){ioe.printStackTrace();}
}
}
客户端任务
包服务器客户端;
导入java.util.concurrent.*;
导入java.net。*;
导入java.io.*;
公共类ClientTask实现可调用{
插座;
客户端任务(套接字){
这个.s=s;
}
公开作废通知(){
BufferedWriter=null;
BufferedReader reader=null;
试一试{
writer=newbufferedwriter(newoutputstreamwriter(s.getOutputStream());
reader=new BufferedReader(new InputStreamReader(s.getInputStream());
作家。写(“平”);
writer.flush();
int i=0;
StringBuilder sb=新的StringBuilder();
而((i=reader.read())!=-1){
System.out.println(“我正在阅读”);
某人附加((字符)i);
}
System.out.println(“服务器发送:“+sb”);
}
catch(IOException ioe){ioe.printStackTrace();}
最后{
试一试{
writer.close();
}
catch(IOException ioe){ioe.printStackTrace();}
if(读卡器!=null){
试一试{
reader.close();
}
catch(IOException ioe){ioe.printStackTrace();}
}
试一试{
s、 close();
}
catch(IOException ioe){ioe.printStackTrace();}
}
返回null;
}
}
问题在于在while
循环中使用BufferedReader.read()
与从连接另一侧处理套接字的方式之间的交互
.read()
仅当从中读取的流结束时返回-1,在本例中,这基本上意味着套接字已关闭。在套接字关闭之前,服务器只是阻塞读取
,等待客户端发送另一个字符。由于服务器正在阻塞读取
,它将永远无法发送回“pong”。客户端正在阻止自己的读取,但最终会达到超时
TCP套接字用于处理数据流。如果您想使用它发送离散的消息,您需要在客户端和服务器之间强加一个协议,以便它们都知道完整消息何时到达。在这种情况下,客户机和服务器可以同意使用终止符字符来指定消息是完整的。例如,他们可以同意在每条消息之后发送一个作为终止符的\n
例如,在您的客户机中,相关代码如下所示:
writer.write("ping");
writer.write('\n');
writer.flush();
int i=0;
StringBuilder sb=new StringBuilder();
while((i=reader.read())!=-1){
char c = (char)i;
if(c == '\n')
break;
sb.append(c);
}
System.out.println("The server sends: "+sb);
非常感谢,特别是你的解释!它现在正在运行,我学到了关于网络的另一件事^^
package serverClient;
import java.util.concurrent.*;
import java.net.*;
import java.io.*;
public class ServerTask implements Callable <Void> {
Socket s;
ServerTask(Socket s){
this.s=s;
}
public Void call(){
BufferedWriter writer=null;
BufferedReader reader=null;
try{
reader=new BufferedReader(new InputStreamReader(s.getInputStream()));
writer=new BufferedWriter(new OutputStreamWriter(s.getOutputStream()));
int i=0;
StringBuilder sb=new StringBuilder();
while((i=reader.read())!=-1){
sb.append((char)i);
}
System.out.println("The client sends: "+sb);
writer.write("pong");
writer.flush();
}
catch(IOException ioe){ioe.printStackTrace();}
finally{
try {
writer.close();
}
catch (IOException ioe) {ioe.printStackTrace();}
if(reader!=null){
try{
reader.close();
}
catch(IOException ioe){ioe.printStackTrace();}
}
try{
s.close();
}
catch(IOException ioe){ioe.printStackTrace();}
}
return null;
}
}
package serverClient;
import java.io.IOException;
import java.net.*;
import java.util.concurrent.*;
public class Client {
public static void main(String[] args) {
ExecutorService es= Executors.newSingleThreadExecutor();
try {
Socket s= new Socket(InetAddress.getLocalHost(),1027);
try {
s.setSoTimeout(50000);
}
catch(SocketException se){se.printStackTrace();}
Callable<Void> task=new ClientTask(s);
es.submit(task);
}
catch (UnknownHostException uhe) {uhe.printStackTrace();}
catch (IOException ioe) {ioe.printStackTrace();}
}
}
package serverClient;
import java.util.concurrent.*;
import java.net.*;
import java.io.*;
public class ClientTask implements Callable <Void>{
Socket s;
ClientTask(Socket s){
this.s=s;
}
public Void call(){
BufferedWriter writer=null;
BufferedReader reader=null;
try{
writer=new BufferedWriter(new OutputStreamWriter(s.getOutputStream()));
reader=new BufferedReader(new InputStreamReader(s.getInputStream()));
writer.write("ping");
writer.flush();
int i=0;
StringBuilder sb=new StringBuilder();
while((i=reader.read())!=-1){
System.out.println("I'm reading.");
sb.append((char)i);
}
System.out.println("The server sends: "+sb);
}
catch(IOException ioe){ ioe.printStackTrace();}
finally{
try {
writer.close();
}
catch (IOException ioe) {ioe.printStackTrace();}
if(reader!=null){
try{
reader.close();
}
catch(IOException ioe){ioe.printStackTrace();}
}
try{
s.close();
}
catch(IOException ioe){ioe.printStackTrace();}
}
return null;
}
}
writer.write("ping");
writer.write('\n');
writer.flush();
int i=0;
StringBuilder sb=new StringBuilder();
while((i=reader.read())!=-1){
char c = (char)i;
if(c == '\n')
break;
sb.append(c);
}
System.out.println("The server sends: "+sb);