如何使用具有泛型HashMap的实例初始值设定项？ [英] How to use an instance initializer with a generic HashMap?

问题描述

你可以使用一个具有泛型HashMap的实例初始化器吗？

Can you use an instance initializer with a generic HashMap?

我在线找到了这个代码，但是很难将它转换为泛型HashMap而不是基本的HashMap ：

I found this code online, but am having trouble converting it to a generic HashMap instead of a basic HashMap:

someMethodThatTakesAHashMap(new HashMap(){{put("a","value-a"); put("c","value-c");}}); 

推荐答案

以下是操作方法：

Here's how:

class Foo {

  static void someMethodThatTakesAHashMap(HashMap<String, String> map) {
    System.out.println(map);  
  }

  public static void main(String[] args) {
    someMethodThatTakesAHashMap(new HashMap<String, String>(){{put("a","value-a"); put("c","value-c");}});
  }
}

编辑：关于压缩serial-ID：是的，你可以这样做，但我会重写它：

about the suppressing of the serial-ID: yes, you could do that, but I'd rewrite it like this:

public class Foo {

  static void someMethodThatTakesAHashMap(Map<String, String> map) {
    System.out.println(map);  
  }

  public static void main(String[] args) {
    HashMap<String, String> map  = new HashMap<String, String>();
    map.put("a","value-a"); 
    map.put("c","value-c");
    someMethodThatTakesAHashMap(map);
  }
}

不需要压缩，更好读取，IMO 。

No suppressing needed, and much better to read, IMO.

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