Java中IO操作：文件读写、网络通信等实例分析

原创青旅半醒 2024-11-06 18:04 26阅读 0赞

Java中IO（输入/输出）操作是程序与外部世界交互的重要方式。Java提供了多种API来处理文件读写和网络通信。以下是一些基本的实例分析：

### 文件读写####1. 使用`FileInputStream`和`FileOutputStream`读写文件```javaimport java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;

public class FileIOExample {
 public static void main(String[] args) {
String filePath = "example.txt";

//写入文件 try (FileOutputStream fos = new FileOutputStream(filePath)) {
 fos.write("Hello, World!".getBytes());
} catch (IOException e) {
e.printStackTrace();
 }

//读取文件 try (FileInputStream fis = new FileInputStream(filePath)) {
int content;
 while ((content = fis.read()) != -1) {
 System.out.print((char) content);
 }
} catch (IOException e) {
e.printStackTrace();
 }
 }
}
```####2. 使用`BufferedReader`和`BufferedWriter`读写文件```javaimport java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;

public class BufferedFileIOExample {
 public static void main(String[] args) {
String filePath = "example.txt";

//写入文件 try (BufferedWriter bw = new BufferedWriter(new FileWriter(filePath))) {
 bw.write("Hello, World!");
} catch (IOException e) {
e.printStackTrace();
 }

//读取文件 try (BufferedReader br = new BufferedReader(new FileReader(filePath))) {
String line;
 while ((line = br.readLine()) != null) {
 System.out.println(line);
 }
} catch (IOException e) {
e.printStackTrace();
 }
 }
}
```###网络通信####1. 使用`Socket`和`ServerSocket`进行TCP通信```javaimport java.io.*;
import java.net.*;

public class TCPClientServerExample {
 public static void main(String[] args) throws IOException {
//服务器端 try (ServerSocket serverSocket = new ServerSocket(1234)) {
 System.out.println("Server is listening on port1234");
 try (Socket clientSocket = serverSocket.accept()) {
 try (BufferedReader in = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
 BufferedWriter out = new BufferedWriter(new OutputStreamWriter(clientSocket.getOutputStream()))) {
String inputLine;
 while ((inputLine = in.readLine()) != null) {
 System.out.println("Client says: " + inputLine);
out.write("Server received your message");
out.newLine();
out.flush();
 }
 }
 }
} catch (IOException e) {
e.printStackTrace();
 }

//客户端 try (Socket socket = new Socket("localhost",1234);
 BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
 BufferedWriter out = new BufferedWriter(new OutputStreamWriter(socket.getOutputStream()))) {
out.write("Hello from client");
out.newLine();
out.flush();
String fromServer;
 while ((fromServer = in.readLine()) != null) {
 System.out.println("Server says: " + fromServer);
 }
} catch (IOException e) {
e.printStackTrace();
 }
 }
}
```####2. 使用`DatagramSocket`和`DatagramPacket`进行UDP通信```javaimport java.io.*;
import java.net.*;

public class UDPClientServerExample {
 public static void main(String[] args) throws IOException {
//服务器端 try (DatagramSocket serverSocket = new DatagramSocket(1234)) {
 System.out.println("Server is listening on port1234");
byte[] receiveData = new byte[1024];
 DatagramPacket receivePacket = new DatagramPacket(receiveData, receiveData.length);
 serverSocket.receive(receivePacket);
String sentence = new String(receivePacket.getData(),0, receivePacket.getLength());
 System.out.println("RECEIVED: " + sentence);
} catch (IOException e) {
e.printStackTrace();
 }

//客户端 try (DatagramSocket clientSocket = new DatagramSocket()) {
String sentence = "Hello from client";
byte[] buf = sentence.getBytes();
 InetAddress IPAddress = InetAddress.getByName("localhost");
 DatagramPacket sendPacket = new DatagramPacket(buf, buf.length, IPAddress,1234);
 clientSocket.send(sendPacket);
} catch (IOException e) {
e.printStackTrace();
 }
 }
}
```这些示例展示了Java中基本的文件读写和网络通信操作。实际应用中，你可能需要根据具体需求进行更复杂的错误处理和功能扩展。