Java 为什么跳过第三个printstream println()命令?
我正在编写一个服务器/客户机程序,其中服务器向客户机发送消息,反之亦然。除了Java 为什么跳过第三个printstream println()命令?,java,printstream,Java,Printstream,我正在编写一个服务器/客户机程序,其中服务器向客户机发送消息,反之亦然。除了printRemoteAddress()方法中的out.println语句之外,它工作得非常好“HELLO1”和“HELLO2”打印到客户端,但“HELLO3”不打印到客户端 我的问题是,为什么“HELLO3”不打印到客户端,而前两个打印到客户端 服务器代码: class Worker extends Thread { Socket sock; Worker (Socket s) {sock = s;} p
printRemoteAddress()
方法中的out.println
语句之外,它工作得非常好<代码>“HELLO1”和“HELLO2”
打印到客户端,但“HELLO3
”不打印到客户端
我的问题是,为什么“HELLO3”
不打印到客户端,而前两个打印到客户端
服务器代码:
class Worker extends Thread {
Socket sock;
Worker (Socket s) {sock = s;}
public void run() {
PrintStream out = null;
BufferedReader in = null;
try {
in = new BufferedReader(new InputStreamReader(sock.getInputStream()));
out = new PrintStream(sock.getOutputStream());
try {
String name;
name = in.readLine();
System.out.println("Looking up " + name);
printRemoteAddress(name, out);
} catch (IOException x) {
System.out.println("Server read error");
x.printStackTrace();
}
sock.close();
} catch (IOException ioe) {System.out.println(ioe);}
}
static void printRemoteAddress (String name, PrintStream out) {
try {
out.println("HELLO1");
out.println("HELLO2");
out.println("HELLO3");
InetAddress machine = InetAddress.getByName(name);
} catch(UnknownHostException ex) {
out.println ("Failed in attempt to look up " + name);
}
}
public class InetServer {
public static void main(String a[]) throws IOException {
int q_len = 6;
int port = 2000;
Socket sock;
ServerSocket servsock = new ServerSocket(port, q_len);
System.out.println
("Inet server 1.8 starting up, listening at port 2000.\n");
while (true) {
sock = servsock.accept();
new Worker(sock).start();
}
}
客户端代码:
public class InetClient {
public static void main (String args[]) {
String serverName;
if (args.length < 1) serverName = "localhost";
else serverName = args[0];
System.out.println("Inet Client, 1.0.\n");
System.out.println("Using server: " + serverName + ", Port: 2000");
BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
try {
String name;
do {
System.out.print("Enter hostname of IP address: ");
System.out.flush();
name = in.readLine();
if (name.indexOf("stop") < 0)
getRemoteAddress(name, serverName);
} while (name.indexOf("stop") < 0);
System.out.println("Process stopped.");;
} catch (IOException x) {x.printStackTrace();}
}
static void getRemoteAddress (String name, String serverName) {
Socket sock;
BufferedReader fromServer;
PrintStream toServer;
String textFromServer;
try {
sock = new Socket(serverName, 2000);
fromServer = new BufferedReader (new InputStreamReader(sock.getInputStream()));
toServer = new PrintStream(sock.getOutputStream());
toServer.println(name);
toServer.flush();
for (int i = 1; i <3; i++) {
textFromServer = fromServer.readLine();
if (textFromServer != null) System.out.println(textFromServer);
}
sock.close();
} catch (IOException x) {
System.out.println("Socket error.");
x.printStackTrace();
}
}
公共类客户端{
公共静态void main(字符串参数[]){
字符串serverName;
如果(args.length<1)serverName=“localhost”;
else serverName=args[0];
System.out.println(“Inet客户端,1.0.\n”);
System.out.println(“使用服务器:+serverName+”,端口:2000”);
BufferedReader in=新的BufferedReader(新的InputStreamReader(System.in));
试一试{
字符串名;
做{
System.out.print(“输入IP地址的主机名:”);
System.out.flush();
name=in.readLine();
if(name.indexOf(“stop”)<0)
getRemoteAddress(名称、服务器名称);
}while(name.indexOf(“stop”)<0);
System.out.println(“进程停止”);;
}catch(iox异常){x.printStackTrace();}
}
静态无效getRemoteAddress(字符串名称、字符串服务器名称){
插座;
来自服务器的BufferedReader;
打印流到服务器;
字符串textFromServer;
试一试{
sock=新套接字(serverName,2000);
fromServer=new BufferedReader(新的InputStreamReader(sock.getInputStream());
toServer=newprintstream(sock.getOutputStream());
toServer.println(名称);
toServer.flush();
对于(int i=1;i
println()
不是“跳过的”,而是缓冲的,不会自动刷新换行符。您可以使用第二个参数来构造它,或者根据需要调用flush()
,或者使用PrintWriter
您还应该关闭PrintStream/PrintWriter
,而不是Socket
,即使我使用autoflosh构建它(out=new PrintStream(sock.getOutputStream(),true);
),它仍然不工作。在每个out.println()之间插入out.flush()
命令
语句。那么您的客户机代码一定有问题,您还没有发布。请将其编辑到您的问题中。您需要先检查readLine()
的结果是否为null,然后再对其执行其他操作,如果您得到它,请关闭套接字。在您的客户机代码中:for(int i=1;谢谢。我将其更改为
for (int i = 1; i <3; i++) {
for (int i = 1; i <= 3; i++) {
while ((textFromServer = fromServer.readLine()) != null {
System.out.println(textFromServer);
}