Javareflect 简明教程

java.lang.reflect - Field Class

Introduction

java.lang.reflect.Field 类提供有关类或接口的单个字段的信息和动态访问权限。反射字段可以是类（静态）字段或实例字段。Field 允许在获取或设置访问操作期间进行扩展转换，但如果出现缩小转换，则会抛出 IllegalArgumentException。

The java.lang.reflect.Field class provides information about, and dynamic access to, a single field of a class or an interface. The reflected field may be a class (static) field or an instance field. A Field permits widening conversions to occur during a get or set access operation, but throws an IllegalArgumentException if a narrowing conversion would occur.

Class declaration

以下是 java.lang.reflect.Field 类的声明 −

Following is the declaration for java.lang.reflect.Field class −

public final class Field
   extends AccessibleObject
      implements Member

Class methods

Sr.No.

Method & Description

1

boolean equals(Object obj)Compares this Field against the specified object.

2

Object get(Object obj)Returns the value of the field represented by this Field, on the specified object.

3

<T extends Annotation> T getAnnotation(Class<T> annotationClass)Returns this element’s annotation for the specified type if such an annotation is present, else null.

4

boolean getBoolean(Object obj)Gets the value of a static or instance boolean field.

5

byte getByte(Object obj)Gets the value of a static or instance byte field.

6

char getChar(Object obj)Gets the value of a static or instance field of type char or of another primitive type convertible to type char via a widening conversion.

7

Annotation[] getDeclaredAnnotations()Returns all annotations that are directly present on this element.

8

Class<?> getDeclaringClass()Returns the Class object representing the class or interface that declares the field represented by this Field object.

9

double getDouble(Object obj)Gets the value of a static or instance field of type double or of another primitive type convertible to type double via a widening conversion.

10

float getFloat(Object obj)Gets the value of a static or instance field of type float or of another primitive type convertible to type float via a widening conversion.

11

Type getGenericType()Returns a Type object that represents the declared type for the field represented by this Field object.

12

int getInt(Object obj)Gets the value of a static or instance field of type int or of another primitive type convertible to type int via a widening conversion.

13

long getLong(Object obj)Gets the value of a static or instance field of type long or of another primitive type convertible to type long via a widening conversion.

14

int getModifiers()Returns the Java language modifiers for the field represented by this Field object, as an integer.

15

String getName()RReturns the name of the field represented by this Field object.

16

short getShort(Object obj)Gets the value of a static or instance field of type short or of another primitive type convertible to type short via a widening conversion.

17

Class<?> getType()Returns a Class object that identifies the declared type for the field represented by this Field object.

18

int hashCode()Returns a hashcode for this Field.

19

boolean isEnumConstant()Returns true if this field represents an element of an enumerated type; returns false otherwise.

20

boolean isSynthetic()This method returns true if the field represented by the current object is synthetic, else it returns false.

21

void setBoolean(Object obj, boolean z)Sets the value of a field as a boolean on the specified object.

22

void setByte(Object obj, byte b)Sets the value of a field as a byte on the specified object.

23

void setChar(Object obj, char c)Sets the value of a field as a char on the specified object.

24

void setDouble(Object obj, double d)Sets the value of a field as a double on the specified object.

25

void setFloat(Object obj, float f)Sets the value of a field as a float on the specified object.

26

void setInt(Object obj, int i)Sets the value of a field as an int on the specified object.

27

void setLong(Object obj, long l)Sets the value of a field as a long on the specified object.

28

void setShort(Object obj, short s)Sets the value of a field as a short on the specified object.

29

String toGenericString()Returns a string describing this Field, including its generic type.

30

String toString()Returns a string describing this Field.

Methods inherited

此类从以下类中继承方法：

This class inherits methods from the following classes −

  1. java.lang.reflect.AccessibleObject

  2. java.lang.Object