用bufferedwriter或randomAccessfile
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileWriter;
import java.util.Scanner;
public class WriterDemo {
public static void main(String[] args) throws Exception {
Scanner in = new Scanner(System.in);
BufferedWriter bw=new BufferedWriter(new FileWriter(new File("D:\\test.txt")));
for(int i=0;i<10;i++) {
String line = in.nextLine();
bw.write(line);
}
bw.flush();
bw.close();
System.out.println("读取文件大小");
File file = new File("d:\\test.txt");
System.out.println("文件大小是："+file.length());
}
}
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
public class Data {
public static void main(String[] args) throws IOException {
BufferedWriter bw=new BufferedWriter(new FileWriter(new File("D://test.txt")));
bw.write("1223");
bw.flush();
bw.close();
System.out.println("写入成功");
}
}
// 异步写入文件
CompletableFileWriter writer = AIOFileWriter.of(Paths.get("systemIn.txt"));
try (Scanner scanner = new Scanner(System.in)) {
while (scanner.hasNext()) {
String line = scanner.next();
if ("bye".equals(line)) {
break;
}
writer.write(line + System.lineSeparator());
}
writer.getPosition().whenComplete((size, error) -> {
if (error != null) {
error.printStackTrace();
}
System.out.println("输入字节数：" + size);
});
}