Java 用jdk8处理异常

我正在用C语言处理我的异常，委托方式如下：

public void QueryIpRanges(Action<ObservableCollection<LocationRange>, Exception> callback)
        {
            try
            {
                var ranges = from e in _xml.Descendants("computer")
                    select new LocationRange
                    {
                        Name = e.Attribute("prefix").Value,
                        Addresses = new ObservableCollection<IpRange>(
                            from i in e.Descendants("range")
                            select new IpRange
                            {
                                Start = i.Element("start").Value,
                                End = i.Element("end").Value,
                                Subnet = i.Element("subnet").Value,
                                Gateway = i.Element("gateway").Value
                            })
                    };

                callback(new ObservableCollection<LocationRange>(ranges), null);
            }
            catch (FormatException ex)
            {
                callback(null, ex);
            }
            catch (ArgumentNullException ex)
            {
                callback(null, ex);
            }

        }

正如您在上面看到的，我使用委托来传递异常（如果发生）。

---

我的问题是，在Java8中如何使用lambda实现这一点。在Java8中处理异常最干净的方法是什么

在Java中，您可以用类似的方法来实现这一点。您需要一个具有两个参数的函数接口，例如java.util.function.BiConsumer。然后它会像这样：

public void queryIpRanges(BiConsumer<ObservableCollection<LocationRange>, Exception> callback) {
    try {
        // ...

        callback.accept(new ObservableCollection<LocationRange>(ranges), null);
    }
    catch (FormatException ex) {
        callback.accept(null, ex);
    }
    catch (ArgumentNullException ex) {
        callback.accept(null, ex);
    }
}

public class Program {
    public static void main(String[] args) {
        final int[] myInt = new int[1];
        tryParseInt("123", (rs, ex) -> {
            if (ex == null) {
                myInt[0] = rs;
            } else {
                ex.printStackTrace();
                System.exit(1);
            }
        });
        System.out.println("myInt = " + myInt[0]);
    }

    static void tryParseInt(String text, Callback<Integer, NumberFormatException> callback) {
        try {
            callback.publish(Integer.parseInt(text), null);
        } catch (NumberFormatException ex) {
            callback.publish(null, ex);
        }
    }
}

@FunctionalInterface
interface Callback<T, E extends Exception> {
    void publish(T result, E ex);
}

---

这样做：

public void queryIpRanges(BiConsumer<ObservableCollection<LocationRange>, Exception> callback) {
    try {
        // ...

        callback.accept(new ObservableCollection<LocationRange>(ranges), null);
    }
    catch (FormatException ex) {
        callback.accept(null, ex);
    }
    catch (ArgumentNullException ex) {
        callback.accept(null, ex);
    }
}

public class Program {
    public static void main(String[] args) {
        final int[] myInt = new int[1];
        tryParseInt("123", (rs, ex) -> {
            if (ex == null) {
                myInt[0] = rs;
            } else {
                ex.printStackTrace();
                System.exit(1);
            }
        });
        System.out.println("myInt = " + myInt[0]);
    }

    static void tryParseInt(String text, Callback<Integer, NumberFormatException> callback) {
        try {
            callback.publish(Integer.parseInt(text), null);
        } catch (NumberFormatException ex) {
            callback.publish(null, ex);
        }
    }
}

@FunctionalInterface
interface Callback<T, E extends Exception> {
    void publish(T result, E ex);
}