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Java中socket使用getInputStream()阻塞问题怎么解决

发表于：2024-09-29 作者：千家信息网编辑

千家信息网最后更新 2024年09月29日，这篇文章主要介绍"Java中socket使用getInputStream()阻塞问题怎么解决"，在日常操作中，相信很多人在Java中socket使用getInputStream()阻塞问题怎么解决问题

千家信息网最后更新 2024年09月29日Java中socket使用getInputStream()阻塞问题怎么解决

这篇文章主要介绍"Java中socket使用getInputStream()阻塞问题怎么解决"，在日常操作中，相信很多人在Java中socket使用getInputStream()阻塞问题怎么解决问题上存在疑惑，小编查阅了各式资料，整理出简单好用的操作方法，希望对大家解答"Java中socket使用getInputStream()阻塞问题怎么解决"的疑惑有所帮助！接下来，请跟着小编一起来学习吧！

socket使用getInputStream()阻塞

今天用socket进行编程练习时，发现程序到了getInputStream(）这里就进行不下去了

Socket socket = new Socket("127.0.0.1", 800);ObjectInputStream reader = new ObjectInputStream(socket.getInputStream());System.out.println("a");ObjectOutputStream writer = new ObjectOutputStream(socket.getOutputStream());

就这样的一个测试代码，a不会打印出来

后来发现是getInputStream(）会一直阻塞在那里阻塞

我把两行代码调了一下就好了，还不太清楚原因，先记下来

Socket socket = new Socket("127.0.0.1", 800);ObjectOutputStream writer = new ObjectOutputStream(socket.getOutputStream());System.out.println("a");ObjectInputStream reader = new ObjectInputStream(socket.getInputStream());

用线程解决Socket的getInputStream阻塞

1.背景

在Socket通信中，当我们希望传输对象时，往往会用到输入/输出对象流。

ObjectInputStream in=new ObjectInputStream(socket.getInputStream());ObjectOutputStream out=new ObjectOutputStream(socket.getOutputStream());

2.问题

当程序调用socket.getInputStream()程序被被卡住。

3.原因

socket.getInputStream()方法会导致程序阻塞，直到inputStream收到对方发过来的报文消息，程序才会继续往下执行。

public ObjectInputStream(InputStream in) throws IOException的官方API显示：
Creates an ObjectInputStream that reads from the specified InputStream. A serialization stream header is read from the stream and verified. This constructor will block until the corresponding ObjectOutputStream has written and flushed the header. [1]

4.解决办法

用线程的方式处理输入流。以下为示例代码：

//===============客户端代码 SocketClient.java=====================

import java.io.IOException;import java.io.ObjectInputStream;import java.io.ObjectOutputStream;import java.net.Socket;import java.net.UnknownHostException;  public class SocketClient {        private Socket socket;        private ObjectOutputStream out;        private ObjectInputStream in;         public SocketClient(){                try {                        socket=new Socket("localhost",8081);                        out=new ObjectOutputStream(socket.getOutputStream());                        ReadThread readThread=new ReadThread();                        readThread.start();                } catch (UnknownHostException e) {                        e.printStackTrace();                } catch (IOException e) {                        e.printStackTrace();                }        }                public void sendMessage(String msg){                System.out.println("send message:"+msg);                try {                        out.writeObject(msg);                        out.flush();                } catch (IOException e) {                        e.printStackTrace();                }        }                class ReadThread extends Thread{                boolean runFlag=true;                public void run(){                        try {                                in=new ObjectInputStream(socket.getInputStream());                        } catch (IOException e1) {                                e1.printStackTrace();                        }                        while(runFlag){                                if(socket.isClosed()){                                        return;                                }                                try {                                        Object obj=in.readObject();                                        if(obj instanceof String){                                                System.out.println("Client recive:"+obj);                                        }                                }                                 catch (IOException e) {                                        e.printStackTrace();                                }                                 catch (ClassNotFoundException e) {                                        e.printStackTrace();                                }                        }                }                                public void exit(){                        runFlag=false;                }        }                public static void main(String[] args) {                SocketClient socketClient=new SocketClient();                System.out.println("build socketClient");                try {                        Thread.sleep(1000);                } catch (InterruptedException e) {                        e.printStackTrace();                }                socketClient.sendMessage("Hello first.");                try {                        Thread.sleep(1000);                } catch (InterruptedException e) {                        e.printStackTrace();                }                socketClient.sendMessage("Hello second.");        } }

//============服务器端代码 SocketService.java===========

import java.io.IOException;import java.io.ObjectInputStream;import java.io.ObjectOutputStream;import java.net.ServerSocket;import java.net.Socket;import java.net.SocketException;import java.util.Date; public class SocketService {        ServerSocket serverSocket;         public SocketService(){                try {                        serverSocket=new ServerSocket(8081);                        while(true){                                Socket socket=serverSocket.accept();                                SocketServiceThread sst=new SocketServiceThread(socket);                                sst.start();                        }                } catch (IOException e) {                        e.printStackTrace();                }        }                class SocketServiceThread extends Thread{                Socket socket;                ObjectInputStream in;                ObjectOutputStream out;                boolean runFlag=true;                public SocketServiceThread(Socket socket){                        if(null==socket){                                runFlag=false;                                return;                        }                        this.socket=socket;                        try {                                out=new ObjectOutputStream(socket.getOutputStream());                        } catch (IOException e) {                                e.printStackTrace();                        }                }                                public void run(){                        if(null==socket){                                System.out.println("socket is null");                                return;                        }                        try {                                in=new ObjectInputStream(socket.getInputStream());                                while(runFlag){                                        if(socket.isClosed()){                                                System.out.println("socket is closed");                                                return;                                        }                                        try {                                                String obj=(String)in.readObject();                                                if(obj instanceof String){                                                        System.out.println("Server recive:"+obj);                                                        Date date=new Date();                                                        out.writeObject("["+date+"]"+obj);                                                        out.flush();                                                }                                                else{                                                        System.out.println("Server recive:"+obj);                                                }                                        }                                         catch (ClassNotFoundException e) {                                                e.printStackTrace();                                        }                                        catch (SocketException e){                                                e.printStackTrace();                                                return;                                        }                                        catch (IOException e){                                                e.printStackTrace();                                        }                                }                        } catch (IOException e1) {                                e1.printStackTrace();                                return;                        } catch (Exception e){                                return;                        }                }                                public void exit(){                        runFlag=false;                }        }                public static void main(String[] args) {                System.out.println("===============start service===============");                new SocketService();        } }