代码示例：

package filestring;import java.io.*;public class FileTest {    public static void main(String[] args) {        try {            // 创建目录            File dir = new File("Chapter");            dir.mkdirs();                        // 创建文件            File f = new File("D:/eclipseWJ/HelloWorld/Chapter/File1.txt");            f.createNewFile();                        // 写入文件            FileWriter writer = new FileWriter(f);            BufferedWriter bufferedwriter = new BufferedWriter(writer);            bufferedwriter.write("File1");            bufferedwriter.close();            // 输出目录中的文件            if (dir.isDirectory()) {                String[] fileContents = dir.list();                for (String i : fileContents)                    System.out.println(i);            }            // 读出文件内容            FileReader fileReader = new FileReader(f);            BufferedReader reader = new BufferedReader(fileReader);            String line = null;            while ((line = reader.readLine()) != null)                System.out.println(line);            reader.close();        } catch (IOException ex) {            ex.printStackTrace();        } catch (Exception ex) {            ex.printStackTrace();        }    }}