Java Rereflection:查找字段的名称和值 [英] Java Refelection : find field's name and value

问题描述

我上课

如下所示

public class SampleReflection {
      public static final String  TWO_name = "html";
      public static final String  TWO_find = "css";


      public static final String  ONE_KEY_java = "java";
      public static final String  ONE_KEY_jsp = "jsp";
      public static final String  ONE_KEY_oracle = "oracle";
      public static final String  ONE_KEY_spring = "spring";
      public static final String  ONE_KEY_struts = "struts";

}

我想获取所有以 ONE_KEY 开头的字段及其值.

I would like to get all the fields which starts with ONE_KEY and their value.

因为 ONE_KEY_xxx 可以是任何数字.

如何在Java反射中或在Java中以其他方式执行此操作?

how to do this in java reflection or any other way in java ?

谢谢

推荐答案

您可以使用 SampleReflection.class.getDeclaredFields()，遍历结果并按名称过滤.然后调用 field.get(null)以获取静态字段的值.如果还要访问非公共字段，则可能必须调用 first.setAccessible(true)(前提是安全管理器允许这样做).

You can use SampleReflection.class.getDeclaredFields(), iterate over the result and filter by name. Then call field.get(null) to get the value of the static fields. If you want to access non-public fields as well you might have to call first.setAccessible(true) (provided the security manager allows that).

或者，您可以查看Apache Common的反射实用程序，例如 FieldUtils 之类.

Alternatively you could have a look at Apache Common's reflection utilities, e.g. FieldUtils and the like.

根据您实际想要实现的目标，可能会有更好的方法，例如使用地图，枚举等.

Depending on what you actually want to achieve there might be better approaches though, e.g. using a map, enums etc.

在您拥有静态字段的情况下，使用枚举可能是一种更好的方法.示例:

In your case where you have static fields using an enum might be a better way to go. Example:

enum SampleFields {
  TWO_name("html"),
  TWO_find("css"),
  ONE_KEY_java("java"),
  ONE_KEY_jsp("jsp");
  ONE_KEY_oracle("oracle"),
  ...;

  private String value;

  private SampleFields(String v) { 
    value = v;
  }
}

然后遍历 SampleFields.values()并按名称进行过滤.

Then iterate over SampleFields.values() and filter by name.

或者，如果满足您的需要，则可以拆分名称，然后将映射传递给枚举值，例如

Alternatively, if that fits your needs, you could split the names and pass a map to the enum values, e.g.

enum SampleFields {
  TWO(/*build a map "name"->"html","find"->"css")*/ ),
  ONE_KEY(/*build a map "java"->"java","jsp"->"jsp", ...*/);

  private Map<String, String> values;

  private SampleFields(Map<String, String> map) { 
    values = map;
  }
}

然后获取如下枚举值: SampleFields.valueOf("ONE_KEY").get("java")

Then get the enum values like this: SampleFields.valueOf("ONE_KEY").get("java")

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