Java 中的 Field getShort()方法,带示例

原文:https://www . geesforgeks . org/field-getshort-method-in-Java-with-examples/

java.lang.reflect.FieldgetShort() 方法用于获取 Short 的值,该值必须是静态或实例字段类型。此方法还用于通过加宽转换获取另一个可转换为 short 类型的基元类型的值。当一个类包含一个静态或实例短字段,并且我们想要得到该字段的值,那么我们可以使用这个方法返回字段的值。

语法:

public short getShort(Object obj)
             throws IllegalArgumentException,
                    IllegalAccessException

参数:该方法接受单个参数 obj ,该参数是从中提取短值的对象。

返回值:该方法返回转换为 short 类型的字段的值。

异常:该方法抛出以下异常:

  1. IllegalAccessException: 如果 Field 对象正在执行 Java 语言访问控制,并且底层字段不可访问。
  2. IllegalArgumentException:如果指定的对象不是声明基础字段的类或接口的实例,或者如果字段值不能通过扩展转换转换为 short 类型。
  3. NullPointRexception:如果指定的对象为空,并且该字段是实例字段。
  4. exceptioniniinitializerror:如果此方法引发的初始化失败。

以下程序说明 getShort()方法: 程序 1:

// Java program to demonstrate getShort() method

import java.lang.reflect.Field;

public class GFG {

    public static void main(String[] args)
        throws Exception
    {

        // Create the User class object
        User user = new User();

        // Get the marks field object
        Field field
            = User.class.getField("Marks");

        // Apply getShort Method on User Object
        // to get the value of Marks field
        short value = field.getShort(user);

        // print result
        System.out.println("Value of short Field"
                           + " Marks is " + value);
    }
}

// sample User class
class User {

    // static short values
    public static short Marks = 34;
    public static String name = "Aman";

    public static short getMarks()
    {
        return Marks;
    }

    public static void setMarks(short marks)
    {
        Marks = marks;
    }

    public static String getName()
    {
        return name;
    }

    public static void setName(String name)
    {
        User.name = name;
    }
}

Output:

Value of short Field Marks is 34

程序 2:

// Java program to demonstrate getShort() method

import java.lang.reflect.Field;

public class GFG {

    public static void main(String[] args)
        throws Exception
    {

        // Create the SmallerNumbers class object
        SmallerNumbers smallNo
            = new SmallerNumbers();

        // Get the value field object
        Field field = SmallerNumbers.class
                          .getField("value");

        // Apply getShort Method on field Object
        // to get the value of value field
        short value = field.getShort(smallNo);

        // print result
        System.out.println("Value: " + value);
    }

    // SmallerNumbers class
    static class SmallerNumbers {

        // short field
        public static short value = 999;

        // getter and setter methods
        public static short getValue()
        {
            return value;
        }

        public static void setValue(short value)
        {
            SmallerNumbers.value = value;
        }
    }
}

Output:

Value: 999

参考文献:https://docs . Oracle . com/javase/8/docs/API/Java/lang/reflect/field . html # getShort-Java . lang . object-