Java中的IO操作：文件读写及网络通信案例

原创墨蓝 2024-11-06 23:36 35阅读 0赞

Java中的IO（输入/输出）操作是处理数据流的基础，包括文件读写和网络通信。以下是一些基本的文件读写和网络通信的Java代码示例。

### 文件读写####1.写入文件```javaimport java.io.FileWriter;
import java.io.IOException;

public class FileWriteExample {
 public static void main(String[] args) {
 try {
 FileWriter writer = new FileWriter("example.txt");
 writer.write("Hello, this is a test file.");
 writer.close();
} catch (IOException e) {
e.printStackTrace();
 }
 }
}
```####2.读取文件```javaimport java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;

public class FileReadExample {
 public static void main(String[] args) {
 try {
 BufferedReader reader = new BufferedReader(new FileReader("example.txt"));
String line;
 while ((line = reader.readLine()) != null) {
 System.out.println(line);
 }
 reader.close();
} catch (IOException e) {
e.printStackTrace();
 }
 }
}
```###网络通信####1. 使用Socket进行TCP通信客户端：

```javaimport java.io.*;
import java.net.*;

public class TCPClient {
 public static void main(String[] args) {
 try {
Socket socket = new Socket("localhost",1234);
 PrintWriter out = new PrintWriter(socket.getOutputStream(), true);
 BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
 BufferedReader stdIn = new BufferedReader(new InputStreamReader(System.in));

String userInput;
 while ((userInput = stdIn.readLine()) != null) {
out.println(userInput);
String fromServer = in.readLine();
 System.out.println("From Server: " + fromServer);
 }
out.close();
in.close();
 socket.close();
} catch (IOException e) {
e.printStackTrace();
 }
 }
}
```服务器端：

```javaimport java.io.*;
import java.net.*;

public class TCPServer {
 public static void main(String[] args) {
 try {
ServerSocket serverSocket = new ServerSocket(1234);
 while (true) {
Socket socket = serverSocket.accept();
 PrintWriter out = new PrintWriter(socket.getOutputStream(), true);
 BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
 BufferedReader stdIn = new BufferedReader(new InputStreamReader(System.in));

String fromClient;
 while ((fromClient = in.readLine()) != null) {
 System.out.println("From Client: " + fromClient);
String response = "Echo: " + fromClient;
out.println(response);
 }
in.close();
out.close();
 socket.close();
 }
} catch (IOException e) {
e.printStackTrace();
 }
 }
}
```####2. 使用DatagramSocket进行UDP通信客户端：

```javaimport java.io.*;
import java.net.*;

public class UDPClient {
 public static void main(String[] args) {
 try {
 DatagramSocket socket = new DatagramSocket();
 InetAddress address = InetAddress.getByName("localhost");
byte[] buf = new byte[256];
 BufferedReader stdIn = new BufferedReader(new InputStreamReader(System.in));

String userInput;
 while ((userInput = stdIn.readLine()) != null) {
buf = userInput.getBytes();
 DatagramPacket packet = new DatagramPacket(buf, buf.length, address,1234);
 socket.send(packet);
 DatagramPacket receivePacket = new DatagramPacket(buf, buf.length);
 socket.receive(receivePacket);
String modifiedSentence = new String(receivePacket.getData(),0, receivePacket.getLength());
 System.out.println("FROM SERVER: " + modifiedSentence);
 }
 socket.close();
} catch (IOException e) {
e.printStackTrace();
 }
 }
}
```服务器端：

```javaimport java.io.*;
import java.net.*;

public class UDPServer {
 public static void main(String[] args) {
 try {
 DatagramSocket serverSocket = new DatagramSocket(1234);
byte[] buf = new byte[256];

while (true) {
 DatagramPacket receivePacket = new DatagramPacket(buf, buf.length);
 serverSocket.receive(receivePacket);
String sentence = new String(receivePacket.getData(),0, receivePacket.getLength());
 System.out.println("RECEIVED: " + sentence);
String modifiedSentence = "Echo: " + sentence;
buf = modifiedSentence.getBytes();
 DatagramPacket sendPacket = new DatagramPacket(buf, buf.length, receivePacket.getAddress(), receivePacket.getPort());
 serverSocket.send(sendPacket);
 }
} catch (IOException e) {
e.printStackTrace();
 }
 }
}
```这些代码示例提供了Java中文件读写和网络通信的基本框架。在实际应用中，你可能需要根据具体需求进行调整和优化。