将Getters / Setter添加到一个基类 [英] Adding Getters/Setters to one Base class

问题描述

  public class BaseDomain< T>< p> {
 
 //通用方法在此处
 
} 
 
 public class Domain1扩展BaseDomain< Domain1> {
 
 private int id; 
 
私人字符串名称; 
 
 //只有属性应该存在这里
 
} 
 
 public class Domain2扩展BaseDomain< Domain2> {
 
 private int id; 
 
私人字符串名称; 
 
 //只有属性应该在这里存在
 
} 
  

在上面的场景中，我可以轻松地定义基类中的所有泛型方法，并可以使用泛型将其用于所有域类。但我的问题在于我想设计一个机制，开发人员只需要在域类中定义属性（无需getters / setters），但BaseDomain应该为每个域动态地提供
getters / setters。

任何建议都非常感谢！

解决方案

使用反射你可以做到这一点。

  public class BaseDomain< T> {
 
 
 public String getName（）{
返回this.getClass（）。getField（name）。get（this）; 
} 
 
 public void setName（String value）{
 this.getClass（）。getField（name）。set（this，value）; 
} 
 
} 
  

请注意 this.getClass（）将引用该对象的运行时类，例如 Domain1 。因此，您可以访问这些字段，获取/设置值等。

如果您将属性声明为，则可能需要设置访问权限。私人或保护。它们是 public ，它应该工作。

正如OP提到的，使用 getDeclaredFields（）不会强制你声明公有字段，不幸的是你必须迭代通过（或使用 Map ）以特定名称访问字段。

如果该字段不存在于您的对象实例中，您将得到一个异常。

I got one thought, but not able to figure it out how to implement this.

public class BaseDomain<T>{

//Generic methods goes here

}

public class Domain1 extends BaseDomain<Domain1>{

private int id;

private String name;

//only properties should be present here

}

public class Domain2 extends BaseDomain<Domain2>{

private int id;

private String name;

//only properties should be present here

}

In above scenario, easily I can define all generic methods in base class and can use in all my domain classes by using generics. But My problem here is I want to design a mechanisim by which developer's have to define only properties in a domain class(without getters/setters) however somehow BaseDomain should provide getters/setters dynamically to each domain.

Any suggestion greatly appreciated!

解决方案

With Reflection you can do that.

public class BaseDomain<T>{


    public String getName() {
        return this.getClass().getField("name").get(this);
    }

    public void setName(String value) {
        this.getClass().getField("name").set(this, value);
    }

}

Note that this.getClass() will refer to the runtime class of that object, that is Domain1 for example. So, you can access the fields there, get/set values, etc.

You may need to set access privileges if you declare the properties to private or protected. It they're public, it should work.

As OP mentioned, using getDeclaredFields() will not force you to declare public fields, unfortunately you have to iterate through (or use a Map) to access the Field with a specific name.

If the field is not present in your object instance, you'll get an exception.

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