Java语言是否具有委托特性,类似于c#对委托的支持?
当前回答
我知道这篇文章很旧了,但是Java 8增加了lambdas和函数接口的概念,即任何接口都只有一个方法。它们一起提供了与c#委托类似的功能。查看这里获得更多信息,或者只是谷歌Java Lambdas。 http://cr.openjdk.java.net/~briangoetz/lambda/lambda-state-final.html
其他回答
是或否,但是Java中的委托模式可以这样考虑。本视频教程讲的是活动片段之间的数据交换,具有使用接口的委托排序模式的精髓。
没有,没有。
你可以通过使用反射来获得你可以调用的Method对象来达到同样的效果,另一种方法是创建一个带有单个“invoke”或“execute”方法的接口,然后实例化它们来调用你感兴趣的方法(即使用匿名内部类)。
你可能还会发现这篇文章很有趣/有用:一个Java程序员看c#委托(@blueskyprojects.com)
它不像c#那样有显式的委托关键字,但你可以在Java 8中通过使用函数接口(即任何只有一个方法的接口)和lambda来实现类似的功能:
private interface SingleFunc {
void printMe();
}
public static void main(String[] args) {
SingleFunc sf = () -> {
System.out.println("Hello, I am a simple single func.");
};
SingleFunc sfComplex = () -> {
System.out.println("Hello, I am a COMPLEX single func.");
};
delegate(sf);
delegate(sfComplex);
}
private static void delegate(SingleFunc f) {
f.printMe();
}
每个SingleFunc类型的新对象都必须实现printMe(),因此将它传递给另一个方法(例如委托(SingleFunc))来调用printMe()方法是安全的。
简短的故事:没有。
Introduction The newest version of the Microsoft Visual J++ development environment supports a language construct called delegates or bound method references. This construct, and the new keywords delegate and multicast introduced to support it, are not a part of the JavaTM programming language, which is specified by the Java Language Specification and amended by the Inner Classes Specification included in the documentation for the JDKTM 1.1 software. It is unlikely that the Java programming language will ever include this construct. Sun already carefully considered adopting it in 1996, to the extent of building and discarding working prototypes. Our conclusion was that bound method references are unnecessary and detrimental to the language. This decision was made in consultation with Borland International, who had previous experience with bound method references in Delphi Object Pascal. We believe bound method references are unnecessary because another design alternative, inner classes, provides equal or superior functionality. In particular, inner classes fully support the requirements of user-interface event handling, and have been used to implement a user-interface API at least as comprehensive as the Windows Foundation Classes. We believe bound method references are harmful because they detract from the simplicity of the Java programming language and the pervasively object-oriented character of the APIs. Bound method references also introduce irregularity into the language syntax and scoping rules. Finally, they dilute the investment in VM technologies because VMs are required to handle additional and disparate types of references and method linkage efficiently.
不,但它内部有相似的行为。
在c#中,委托用于创建一个单独的入口点,它们的工作原理很像函数指针。
在java中没有函数指针,但是在内部java需要做同样的事情来实现这些目标。
例如,在Java中创建线程需要一个类扩展Thread或实现Runnable,因为类对象变量可以用作内存位置指针。
推荐文章
- 导致java.lang.VerifyError错误的原因
- 如何在Java中监控计算机的CPU、内存和磁盘使用情况?
- 如何设置超时在改造库?
- java lambda可以有一个以上的参数吗?
- HashMap -获取第一个键值
- 使用Jackson将JSON字符串转换为漂亮的打印JSON输出
- Android - SPAN_EXCLUSIVE_EXCLUSIVE跨度不能为零长度
- Javadoc @see或{@link}?
- 在准备语句中使用“like”通配符
- Android Eclipse -无法找到*.apk
- javac和Eclipse编译器之间的区别是什么?
- 工厂模式和策略模式之间的区别是什么?
- 在Java中使用正则表达式提取值
- 如何允许所有网络连接类型HTTP和HTTPS在Android(9)馅饼?
- Intellij IDEA Java类在保存时不能自动编译