Java Socket 监听 PHP 客户端不工作答案

【问题标题】：Java Socket Listening PHP Client Not WorkJava Socket 监听 PHP 客户端不工作
【发布时间】：2019-08-29 10:10:37
【问题描述】：

我在运行 PHP 客户端向 Java 服务器发送数据时遇到问题，问题是 Java 服务器没有显示来自 PHP 客户端的任何输入流。

当我执行 php 客户端时，Java 服务器输出仅显示“刚刚连接..”，我希望它显示“正在测试”，这是 java 代码：

Waiting for client on port 3000...
Waiting for client on port 3000...
Waiting for client on port 3000...
Waiting for client on port 3000...
Just connected to /127.0.0.1:39220
Waiting for client on port 3000...

PHP 客户端输出：

$ sudo php testSocketClient.php
Try to connect '127.0.0.1' Port '3000'...
Connect OK
Send Message to Server Successfully!
Send Information:Testing

Turn Off Socket...
Turn Off OK

这是我的 PHP 客户端代码，这是我发送“测试”消息的地方：

<?php
set_time_limit(0);

$port = 3000;
$ip   = "127.0.0.1";

$socket = socket_create(AF_INET, SOCK_STREAM, SOL_TCP);

if($socket < 0) {
    echo "socket_create() Fail to create:".socket_strerror($sock)."\n";
} else {
    echo "Try to connect '$ip' Port '$port'...\n";
    $result = socket_connect($socket, $ip, $port);
    if ($result < 0) {
        echo "socket_connect() failed.\nReason: ($result) " . socket_strerror($result) . "\n";
    }else {
        echo "Connect OK\n";

        $in = "Testing\r\n";
        $out = '';

        if(!socket_write($socket, $in, strlen($in))) {
            echo "socket_write() failed. reason: " . socket_strerror($socket) . "\n";
        }else {
            echo "Send Message to Server Successfully!\n";
            echo "Send Information:" . $in . "\n";

            echo "Turn Off Socket...\n";
            socket_close($socket);
            echo "Turn Off OK\n";
        }
    }
}

这是我的 Java 服务器代码：

package TestPackage;

import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.net.ServerSocket;
import java.net.Socket;
import java.net.SocketException;
import java.net.SocketTimeoutException;

public class TestSocketListener {
    public static void main(String[] args) {
        System.out.println("INIT SOCKET");
        int port = 3000;
        while(true) {
            try {
                ServerSocket serverSocket = new ServerSocket(port);
                serverSocket.setSoTimeout(5000);

                System.out.println("Waiting for client on port " +
                        serverSocket.getLocalPort() + "...");
                Socket server = serverSocket.accept();

                System.out.println("Just connected to " + server.getRemoteSocketAddress());
                DataInputStream DataInStream = new DataInputStream(server.getInputStream());

                System.out.println(DataInStream.readUTF());
                DataOutputStream DataOutStream = new DataOutputStream(server.getOutputStream());
                DataOutStream.writeUTF("Thank you for connecting to " + server.getLocalSocketAddress()
                        + "\nGoodbye!");
                server.close();

                System.out.println(("SERVER CLOSED"));
            } catch(SocketTimeoutException st) {
                //System.out.println("Socket timed out!");
            } catch(SocketException s) {
                //System.out.println("Socket Error!!");
                //s.getMessage();
            } catch (IOException e) {
                //System.out.println("IO Error!");
            }
        }
    }
}

这是使用异常时的错误消息（尝试使用不同的端口时发生同样的错误。我正在尝试 3000、4444 和 29299）：

java.net.BindException: Address already in use (Bind failed)
        at java.net.PlainSocketImpl.socketBind(Native Method)
        at java.net.AbstractPlainSocketImpl.bind(AbstractPlainSocketImpl.java:387)
        at java.net.ServerSocket.bind(ServerSocket.java:375)
        at java.net.ServerSocket.<init>(ServerSocket.java:237)
        at java.net.ServerSocket.<init>(ServerSocket.java:128)
        at TestPackage.TestSocketListener.main(TestSocketListener.java:17)

当前使用的端口：

$ nmap 127.0.0.1
Starting Nmap 6.40 ( http://nmap.org ) at 2019-08-01 17:32 WIB
Nmap scan report for localhost (127.0.0.1)
Host is up (0.00046s latency).
Not shown: 994 closed ports
PORT     STATE SERVICE
22/tcp   open  ssh
25/tcp   open  smtp
80/tcp   open  http
111/tcp  open  rpcbind
443/tcp  open  https
3306/tcp open  mysql

【问题讨论】：

您完全忽略了捕获的异常，请考虑打印它们的消息。
我正在更新线程，它显示类似绑定失败
这个错误表明另一个应用程序已经在监听这个端口。检查您是否没有其他 TestSocketListener 实例正在运行，或者当前哪个应用程序正在使用此端口。
我正在使用端口 3000、4444 和 29299，但仍然有相同的错误。我很确定没有应用程序使用此端口，我正在添加 nmap 结果（端口扫描）

标签： java php sockets

【解决方案1】：

我让它工作了。根据 JAVA 文档，如果客户端关闭连接，可能会出现IOException。请参阅：DataInputStream。您的 PHP 代码执行并结束连接。但这仍然不是您的 PHP 代码的问题。您正在使用 readUTF() 方法，它并没有真正告诉 JAVA 要读取多少字节；这不可靠。相反，请使用read([]byte b, int off, int len)

这是我的输出：

INIT SOCKET
Waiting for client on port 3000...
Just connected to /127.0.0.1:61989
Testing

SERVER CLOSED

代码更改如下：

package TestPackage;

import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.InputStream;
import java.io.IOException;
import java.net.ServerSocket;
import java.net.Socket;
import java.net.SocketException;
import java.net.SocketTimeoutException;
import java.nio.channels.IllegalBlockingModeException;

public class TestSocketListener {
    public static void main(String[] args) {
        System.out.println("INIT SOCKET");
        int port = 3000;
        while(true) {
            try {
                ServerSocket serverSocket = new ServerSocket(port);
                serverSocket.setSoTimeout(5000);

                System.out.println("Waiting for client on port " +
                        serverSocket.getLocalPort() + "...");
                Socket server = serverSocket.accept();

                System.out.println("Just connected to " + server.getRemoteSocketAddress());

                // you want to know how much bytes to read
                InputStream inputstream = server.getInputStream();
                int buflen = inputstream.available();

                DataInputStream DataInStream = new DataInputStream(inputstream);

                byte[] rawstring = new byte[buflen];
                DataInStream.read(rawstring, 0, buflen);
                String str = new String(rawstring);
                System.out.println(str);

                DataOutputStream DataOutStream = new DataOutputStream(server.getOutputStream());
                DataOutStream.writeUTF("Thank you for connecting to " + server.getLocalSocketAddress()
                        + "\nGoodbye!");
                server.close();

                System.out.println(("SERVER CLOSED"));
            } catch(SocketTimeoutException st) {
                System.out.println("Socket timed out!");
            } catch(SocketException s) {
                //System.out.println("Socket Error!!");
                //s.getMessage();
            } catch (IOException e) {
                //System.out.println("IO Error!");
            }
        }
    }
}

希望这会有所帮助！

【讨论】：