java getfield

类的类getField()方法 (Class class getField() method)

• getField() method is available in java.lang package.

  getField()方法在java.lang包中可用。

• getField() method is used to return a Field objects that indicate the given public member field of the class or an interface denoted by this Class object.

  getField()方法用于返回一个Field对象，该对象指示该类的给定公共成员字段或由此Class对象表示的接口。

• getField() method is a non-static method, it is accessible with the class object only and if we try to access the method with the class name then we will get an error.

  getField()方法是一个非静态方法，只能通过类对象访问，如果尝试使用类名称访问该方法，则会收到错误消息。

• getField() method may throw an exception at the time of returning a Field object.

  getField()方法在返回Field对象时可能会引发异常。

  • NoSuchFieldException: In this exception when a specifying field does not exist.NoSuchFieldException ：在此异常中，当指定字段不存在时。
  • SecurityException: In this exception, it may raise when the security manager exists.SecurityException ：在此异常中，当安全管理器存在时可能会引发此异常。
  • NullPointerException: In this exception when the given field is null.NullPointerException ：在此异常中，给定字段为null。

Syntax:

句法：

    public Field getField (String field_name);

Parameter(s):

参数：

• String field_name – represents the name of the field.

  字符串field_name –代表字段名称。

Return value:

返回值：

The return type of this method is Field, it returns Field object of the given Field in this Class.

此方法的返回类型为Field ，它返回此类中给定Field的Field对象。

Example:

例：

// Java program to demonstrate the example
// of Field getField (String field_name) method of Class
import java.lang.reflect.*;
public class GetFieldOfClass {public static void main(String[] args) throws Exception {GetFieldOfClass field = new GetFieldOfClass();
// Get Class
Class cl = field.getClass();
// By using getField() method is to get the public field of
// the class
Field f = cl.getField("i");
System.out.println("Field: " + f.toString());
}
// Private Constructors
private GetFieldOfClass() {System.out.println("We are in private constructor");
}
// Public Constructors
public GetFieldOfClass(int i) {this.i = i;
}
public int i = 100;
}

Output

输出量

We are in private constructor
Field: public int GetFieldOfClass.i

翻译自: https://www.includehelp.com/java/class-class-getfield-method-with-example.aspx

java getfield