问一个socket的基本问题
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悬赏园豆：20
[已解决问题]
解决于 2019-05-29 19:11
服务器代码：
public static void main(String[] args) throws IOException {
ServerSocket serverSocket = new ServerSocket(6666);
while (true){
Socket socket = serverSocket.accept();
OutputStream os = socket.getOutputStream();
BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(os));
bw.write("我是服务器");
bw.close();
os.close();
socket.close();
}客户端代码：
public static void main(String[] args) throws IOException {
Socket socket = new Socket("127.0.0.1",6666);
System.out.println("111111111");
InputStream is = socket.getInputStream();
BufferedReader br = new BufferedReader(new InputStreamReader(is));
String data = null;
while ((data = br.readLine()) != null){
System.out.println(data);
}
br.close();
is.close();
System.out.println("2222222222");
socket.close();
}这样是没问题的，客户端读出来服务器写入的信息，但是如果客户端有两个数据流的操作就会报错：Exception in thread "main" java.net.SocketException: Socket is closed，网上查了原因是在自己关闭了socket后进行了流的读写操作，但是我是在最后关闭socket的，
出问题的客户端代码：
public static void main(String[] args) throws IOException {
Socket socket = new Socket("127.0.0.1",6666);
OutputStream os = socket.getOutputStream();
BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(os));
bw.write("我是客户端");
bw.close();
os.close();
System.out.println("111111111");
InputStream is = socket.getInputStream();
BufferedReader br = new BufferedReader(new InputStreamReader(is));
String data = null;
while ((data = br.readLine()) != null){
System.out.println(data);
}
br.close();
is.close();
System.out.println("2222222222");
socket.close();
}这样会成功执行到打印“1111111”，发送给服务器数据成功，接受服务器信息报错
如果把读写顺序反过来：
public static void main(String[] args) throws IOException {
Socket socket = new Socket("127.0.0.1",6666);
InputStream is = socket.getInputStream();
BufferedReader br = new BufferedReader(new InputStreamReader(is));
String data = null;
while ((data = br.readLine()) != null){
System.out.println(data);
}
br.close();
is.close();
System.out.println("111111111");
OutputStream os = socket.getOutputStream();
BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(os));
bw.write("我是客户端");
bw.close();
os.close();
System.out.println("2222222222");
socket.close();
}这样读数据会成功，写数据就会失败。
为什么客户端对socket只能进行一次读或者写的操作,第二次操作流就会失败？
最佳答案
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关闭返回的 OutputStream 将关闭关联套接字
收获园豆：20
其他回答(2)
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while (true){
Socket socket = serverSocket.accept();
OutputStream os = socket.getOutputStream();
BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(os));
bw.write("我是服务器");
bw.close();
os.close();
socket.close();
}都特么关闭了，就是一次while 流程。重新连你就可以再次该过程了。服务器会对应很多这个过程，你需要在accept后开线程。
是这样的，我把服务器端的while去掉，就执行一次，把socket.close()也注释掉，还是有问题，
ServerSocket serverSocket = new ServerSocket(6666);
Socket socket = serverSocket.accept();
InputStream is = socket.getInputStream();
BufferedReader br = new BufferedReader(new InputStreamReader(is));
String data = null;
while ((data = br.readLine()) != null){
System.out.println(data);
}
br.close();
is.close();// socket.close();
服务器打印客户端发送的消息
Socket socket = new Socket("127.0.0.1",6666);
OutputStream os = socket.getOutputStream();
BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(os));
bw.write("我是客户端");
bw.close();
os.close();
InputStream is = socket.getInputStream();
BufferedReader br = new BufferedReader(new InputStreamReader(is));
String data = null;
while ((data = br.readLine()) != null){
System.out.println(data);
}
br.close();
is.close();// socket.close();
报错：
Exception in thread "main" java.net.SocketException: Socket is closed
at java.net.Socket.getInputStream(Socket.java:903)
客户端在发完消息后获取getInputStream()会报错，这是为什么，我都没关socket，我在网上查的socket自动断开很长时间的，难道是我客户端和服务器用一台机子的问题？
0
以找到原因，多谢@海之殇
在关闭从socket获取的输出流或输出流时，(Out/In)putStream.close()方法会指向(Out/In)putStream的子类Socket(Out/In)putStream的close方法，关闭关联的socket，源码如下：
/**
* Closes the stream.
*/
private boolean closing = false;
public void close() throws IOException {
// Prevent recursion. See BugId 4484411
if (closing)
return;
closing = true;
if (socket != null) {
if (!socket.isClosed())
socket.close();
} else
impl.close();
closing = false;
}
