io工具类

文件读写工具类

public class TextFile extends ArrayList<String> {
  // Read a file as a single string:
  public static String read(String fileName) {
    StringBuilder sb = new StringBuilder();
    try {
      BufferedReader in= new BufferedReader(new FileReader(
        new File(fileName).getAbsoluteFile()));
      try {
        String s;
        while((s = in.readLine()) != null) {
          sb.append(s);
          sb.append("\n");
        }
      } finally {
        in.close();
      }
    } catch(IOException e) {
      throw new RuntimeException(e);
    }
    return sb.toString();
  }
  // Write a single file in one method call:
  public static void write(String fileName, String text) {
    try {
      PrintWriter out = new PrintWriter(
        new File(fileName).getAbsoluteFile());
      try {
        out.print(text);
      } finally {
        out.close();
      }
    } catch(IOException e) {
      throw new RuntimeException(e);
    }
  }
  // Read a file, split by any regular expression:
  public TextFile(String fileName, String splitter) {
    super(Arrays.asList(read(fileName).split(splitter)));
    // Regular expression split() often leaves an empty
    // String at the first position:
    if(get(0).equals("")) remove(0);
  }
  // Normally read by lines:
  public TextFile(String fileName) {
    this(fileName, "\n");
  }
  public void write(String fileName) {
    try {
      PrintWriter out = new PrintWriter(
        new File(fileName).getAbsoluteFile());
      try {
        for(String item : this)
          out.println(item);
      } finally {
        out.close();
      }
    } catch(IOException e) {
      throw new RuntimeException(e);
    }
  }
  // Simple test:
  public static void main(String[] args) {
    String file = read("TextFile.java");
    write("test.txt", file);
    TextFile text = new TextFile("test.txt");
    text.write("test2.txt");
    // Break into unique sorted list of words:
    TreeSet<String> words = new TreeSet<String>(
      new TextFile("TextFile.java", "\\W+"));
    // Display the capitalized words:
    System.out.println(words.headSet("a"));
  }
}

二进制文件读取工具类：

public class BinaryFile {
  public static byte[] read(File bFile) throws IOException{
    BufferedInputStream bf = new BufferedInputStream(
      new FileInputStream(bFile));
    try {
      byte[] data = new byte[bf.available()];
      bf.read(data);
      return data;
    } finally {
      bf.close();
    }
  }
  public static byte[]
  read(String bFile) throws IOException {
    return read(new File(bFile).getAbsoluteFile());
  }
}