try-with-resources ‏(AutoCloseable)

مقدمة

مفهوم AutoCloseable

الشفرة: إغلاق FileReader تلقائيًا

public class Main {
  public static void main(String[] args) {
    try (java.io.FileReader fr = new java.io.FileReader("test.txt")) {
      int ch = fr.read();
      System.out.println("First char code=" + ch);
    } catch (java.io.IOException e) {
      System.out.println("Error: " + e.getMessage());
    }
  }
}

موارد متعددة

الشفرة: موردان

public class Main {
  public static void main(String[] args) {
    try (java.io.BufferedReader br = new java.io.BufferedReader(new java.io.FileReader("test.txt"));
         java.io.PrintWriter pw = new java.io.PrintWriter("out.txt")) {
      String line = br.readLine();
      pw.println(line);
    } catch (java.io.IOException e) {
      System.out.println("Error: " + e.getMessage());
    }
  }
}

الشفرة: AutoCloseable مخصّص

public class Main {
  static class MyRes implements AutoCloseable {
    public void use() { System.out.println("Using resource"); }
    public void close() { System.out.println("Closed resource"); }
  }
  public static void main(String[] args) {
    try (MyRes r = new MyRes()) {
      r.use();
    }
  }
}

التحقق من try-with-resources

خلاصة