深入理解Java中的IO操作，通过案例进行实践

原创小灰灰 2024-11-01 04:09 3阅读 0赞

Java中的IO（输入/输出）操作是程序与外部世界交互的基本方式，包括从文件、网络、键盘等读取数据和向屏幕、文件、网络等输出数据。Java提供了多种IO类和接口来处理不同的IO场景。以下是一些基本的IO操作和案例实践：

###1.基本的文件IO操作####读取文件内容```javaimport java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;

public class FileReadExample {
 public static void main(String[] args) {
String path = "example.txt"; //替换为你的文件路径 try (BufferedReader reader = new BufferedReader(new FileReader(path))) {
String line;
 while ((line = reader.readLine()) != null) {
 System.out.println(line);
 }
} catch (IOException e) {
e.printStackTrace();
 }
 }
}
```####写入文件内容```javaimport java.io.BufferedWriter;
import java.io.FileWriter;
import java.io.IOException;

public class FileWriteExample {
 public static void main(String[] args) {
String path = "example.txt"; //替换为你的文件路径String content = "Hello, World!";
 try (BufferedWriter writer = new BufferedWriter(new FileWriter(path))) {
 writer.write(content);
} catch (IOException e) {
e.printStackTrace();
 }
 }
}
```###2. 使用`java.nio`包进行IO操作Java NIO（New IO）提供了一种更高效的方式来处理IO操作，特别是对于大文件和网络IO。

####读取文件```javaimport java.nio.file.Files;
import java.nio.file.Paths;
import java.io.IOException;
import java.util.stream.Stream;

public class NioFileReadExample {
 public static void main(String[] args) {
String path = "example.txt"; //替换为你的文件路径 try (Stream<String> stream = Files.lines(Paths.get(path))) {
stream.forEach(System.out::println);
} catch (IOException e) {
e.printStackTrace();
 }
 }
}
```####写入文件```javaimport java.nio.file.Files;
import java.nio.file.Paths;
import java.nio.file.StandardOpenOption;
import java.io.IOException;
import java.util.Arrays;

public class NioFileWriteExample {
 public static void main(String[] args) {
String path = "example.txt"; //替换为你的文件路径String content = "Hello, World!";
 try {
Files.write(Paths.get(path), Arrays.asList(content.split("\n")), StandardOpenOption.CREATE);
} catch (IOException e) {
e.printStackTrace();
 }
 }
}
```###3.网络IO操作Java提供了`java.net`包来处理网络IO，包括`Socket`和`ServerSocket`类。

####客户端Socket```javaimport java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.Socket;

public class ClientSocketExample {
 public static void main(String[] args) {
 try (Socket socket = new Socket("localhost",1234); //替换为服务器地址和端口 PrintWriter out = new PrintWriter(socket.getOutputStream(), true);
 BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream()))) {
out.println("Hello from client!");
String response = in.readLine();
 System.out.println("Server says: " + response);
} catch (Exception e) {
e.printStackTrace();
 }
 }
}
```####服务器端ServerSocket```javaimport java.io.*;
import java.net.ServerSocket;
import java.net.Socket;

public class ServerSocketExample {
 public static void main(String[] args) {
 try (ServerSocket serverSocket = new ServerSocket(1234); //替换为端口号Socket clientSocket = serverSocket.accept();
 PrintWriter out = new PrintWriter(clientSocket.getOutputStream(), true);
 BufferedReader in = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()))) {
String inputLine;
 while ((inputLine = in.readLine()) != null) {
 System.out.println("Client says: " + inputLine);
out.println("Hello from server!");
 }
} catch (IOException e) {
e.printStackTrace();
 }
 }
}
```这些案例提供了Java IO操作的基本框架，你可以根据具体需求进行扩展和修改。记得在实际应用中处理异常和资源释放。