Package org.apache.commons.lang3.reflect
Class FieldUtils
java.lang.Object
org.apache.commons.lang3.reflect.FieldUtils
Utilities for working with
Fields by reflection. Adapted and refactored from the dormant [reflect] Commons
sandbox component.
The ability is provided to break the scoping restrictions coded by the programmer. This can allow fields to be changed that shouldn't be. This facility should be used with care.
- Since:
- 2.5
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Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionstatic Field[]getAllFields(Class<?> cls) Gets all fields of the given class and its parents (if any).getAllFieldsList(Class<?> cls) Gets all fields of the given class and its parents (if any).static FieldgetDeclaredField(Class<?> cls, String fieldName) Gets an accessibleFieldby name respecting scope.static FieldgetDeclaredField(Class<?> cls, String fieldName, boolean forceAccess) Gets an accessibleFieldby name, breaking scope if requested.static FieldGets an accessibleFieldby name respecting scope.static FieldGets an accessibleFieldby name, breaking scope if requested.getFieldsListWithAnnotation(Class<?> cls, Class<? extends Annotation> annotationCls) Gets all fields of the given class and its parents (if any) that are annotated with the given annotation.static Field[]getFieldsWithAnnotation(Class<?> cls, Class<? extends Annotation> annotationCls) Gets all fields of the given class and its parents (if any) that are annotated with the given annotation.static ObjectreadDeclaredField(Object target, String fieldName) Reads the namedpublicField.static ObjectreadDeclaredField(Object target, String fieldName, boolean forceAccess) Gets aFieldvalue by name.static ObjectreadDeclaredStaticField(Class<?> cls, String fieldName) Gets the value of astaticFieldby name.static ObjectreadDeclaredStaticField(Class<?> cls, String fieldName, boolean forceAccess) Gets the value of astaticFieldby name.static ObjectReads the namedpublicField.static ObjectReads the namedField.static ObjectReads an accessibleField.static ObjectReads aField.static ObjectreadStaticField(Class<?> cls, String fieldName) Reads the namedpublic staticField.static ObjectreadStaticField(Class<?> cls, String fieldName, boolean forceAccess) Reads the namedstaticField.static ObjectreadStaticField(Field field) Reads an accessiblestaticField.static ObjectreadStaticField(Field field, boolean forceAccess) Reads a staticField.static voidremoveFinalModifier(Field field) Removes the final modifier from aField.static voidremoveFinalModifier(Field field, boolean forceAccess) Deprecated.As of Java 12, we can no longer drop thefinalmodifier, thus rendering this method obsolete.static voidwriteDeclaredField(Object target, String fieldName, Object value) Writes apublicField.static voidwriteDeclaredField(Object target, String fieldName, Object value, boolean forceAccess) Writes apublicField.static voidwriteDeclaredStaticField(Class<?> cls, String fieldName, Object value) Writes a namedpublic staticField.static voidwriteDeclaredStaticField(Class<?> cls, String fieldName, Object value, boolean forceAccess) Writes a namedstaticField.static voidwriteField(Object target, String fieldName, Object value) Writes apublicField.static voidwriteField(Object target, String fieldName, Object value, boolean forceAccess) Writes aField.static voidwriteField(Field field, Object target, Object value) Writes an accessibleField.static voidwriteField(Field field, Object target, Object value, boolean forceAccess) Writes aField.static voidwriteStaticField(Class<?> cls, String fieldName, Object value) Writes a namedpublic staticField.static voidwriteStaticField(Class<?> cls, String fieldName, Object value, boolean forceAccess) Writes a namedstaticField.static voidwriteStaticField(Field field, Object value) Writes apublic staticField.static voidwriteStaticField(Field field, Object value, boolean forceAccess) Writes a staticField.
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Constructor Details
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FieldUtils
Deprecated.TODO Make private in 4.0.FieldUtilsinstances should NOT be constructed in standard programming.This constructor is
publicto permit tools that require a JavaBean instance to operate.
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Method Details
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getAllFields
Gets all fields of the given class and its parents (if any).- Parameters:
cls- theClassto query- Returns:
- an array of Fields (possibly empty).
- Throws:
NullPointerException- if the class isnull- Since:
- 3.2
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getAllFieldsList
Gets all fields of the given class and its parents (if any).- Parameters:
cls- theClassto query- Returns:
- a list of Fields (possibly empty).
- Throws:
NullPointerException- if the class isnull- Since:
- 3.2
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getDeclaredField
Gets an accessibleFieldby name respecting scope. Only the specified class will be considered.- Parameters:
cls- theClassto reflect, must not benullfieldName- the field name to obtain- Returns:
- the Field object
- Throws:
NullPointerException- if the class isnullIllegalArgumentException- if the field name isnull, blank, or empty
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getDeclaredField
Gets an accessibleFieldby name, breaking scope if requested. Only the specified class will be considered.- Parameters:
cls- theClassto reflect, must not benullfieldName- the field name to obtainforceAccess- whether to break scope restrictions using theAccessibleObject.setAccessible(boolean)method.falsewill only matchpublicfields.- Returns:
- the Field object
- Throws:
NullPointerException- if the class isnullIllegalArgumentException- if the field name isnull, blank, or empty
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getField
Gets an accessibleFieldby name respecting scope. Superclasses/interfaces will be considered.- Parameters:
cls- theClassto reflect, must not benullfieldName- the field name to obtain- Returns:
- the Field object
- Throws:
NullPointerException- if the class isnullIllegalArgumentException- if the field name isnull, blank, or empty
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getField
Gets an accessibleFieldby name, breaking scope if requested. Superclasses/interfaces will be considered.- Parameters:
cls- theClassto reflect, must not benullfieldName- the field name to obtainforceAccess- whether to break scope restrictions using theAccessibleObject.setAccessible(boolean)method.falsewill only matchpublicfields.- Returns:
- the Field object
- Throws:
NullPointerException- if the class isnullIllegalArgumentException- if the field name is blank or empty or is matched at multiple places in the inheritance hierarchy
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getFieldsListWithAnnotation
public static List<Field> getFieldsListWithAnnotation(Class<?> cls, Class<? extends Annotation> annotationCls) Gets all fields of the given class and its parents (if any) that are annotated with the given annotation.- Parameters:
cls- theClassto queryannotationCls- theAnnotationthat must be present on a field to be matched- Returns:
- a list of Fields (possibly empty).
- Throws:
NullPointerException- if the class or annotation arenull- Since:
- 3.4
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getFieldsWithAnnotation
public static Field[] getFieldsWithAnnotation(Class<?> cls, Class<? extends Annotation> annotationCls) Gets all fields of the given class and its parents (if any) that are annotated with the given annotation.- Parameters:
cls- theClassto queryannotationCls- theAnnotationthat must be present on a field to be matched- Returns:
- an array of Fields (possibly empty).
- Throws:
NullPointerException- if the class or annotation arenull- Since:
- 3.4
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readDeclaredField
public static Object readDeclaredField(Object target, String fieldName) throws IllegalAccessException Reads the namedpublicField. Only the class of the specified object will be considered.- Parameters:
target- the object to reflect, must not benullfieldName- the field name to obtain- Returns:
- the value of the field
- Throws:
NullPointerException- iftargetisnullIllegalArgumentException- iffieldNameisnull, blank or empty, or could not be foundIllegalAccessException- if the named field is notpublic
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readDeclaredField
public static Object readDeclaredField(Object target, String fieldName, boolean forceAccess) throws IllegalAccessException Gets aFieldvalue by name. Only the class of the specified object will be considered.- Parameters:
target- the object to reflect, must not benullfieldName- the field name to obtainforceAccess- whether to break scope restrictions using theAccessibleObject.setAccessible(boolean)method.falsewill only match public fields.- Returns:
- the Field object
- Throws:
NullPointerException- iftargetisnullIllegalArgumentException- iffieldNameisnull, blank or empty, or could not be foundIllegalAccessException- if the field is not made accessible
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readDeclaredStaticField
public static Object readDeclaredStaticField(Class<?> cls, String fieldName) throws IllegalAccessException Gets the value of astaticFieldby name. The field must bepublic. Only the specified class will be considered.- Parameters:
cls- theClassto reflect, must not benullfieldName- the field name to obtain- Returns:
- the value of the field
- Throws:
NullPointerException- if the class isnull, or the field could not be foundIllegalArgumentException- if the field name isnull, blank, empty, or is notstaticIllegalAccessException- if the field is not accessible
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readDeclaredStaticField
public static Object readDeclaredStaticField(Class<?> cls, String fieldName, boolean forceAccess) throws IllegalAccessException Gets the value of astaticFieldby name. Only the specified class will be considered.- Parameters:
cls- theClassto reflect, must not benullfieldName- the field name to obtainforceAccess- whether to break scope restrictions using theAccessibleObject.setAccessible(boolean)method.falsewill only matchpublicfields.- Returns:
- the Field object
- Throws:
NullPointerException- if the class isnull, or the field could not be foundIllegalArgumentException- if the field name is blank or empty, is notstaticIllegalAccessException- if the field is not made accessible
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readField
Reads an accessibleField.- Parameters:
field- the field to usetarget- the object to call on, may benullforstaticfields- Returns:
- the field value
- Throws:
NullPointerException- if the field isnullIllegalAccessException- if the field is not accessible
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readField
public static Object readField(Field field, Object target, boolean forceAccess) throws IllegalAccessException Reads aField.- Parameters:
field- the field to usetarget- the object to call on, may benullforstaticfieldsforceAccess- whether to break scope restrictions using theAccessibleObject.setAccessible(boolean)method.- Returns:
- the field value
- Throws:
NullPointerException- if the field isnullIllegalAccessException- if the field is not made accessible
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readField
Reads the namedpublicField. Superclasses will be considered.- Parameters:
target- the object to reflect, must not benullfieldName- the field name to obtain- Returns:
- the value of the field
- Throws:
NullPointerException- if the target isnullIllegalArgumentException- if the field name isnull, blank, empty, or could not be foundIllegalAccessException- if the named field is notpublic
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readField
public static Object readField(Object target, String fieldName, boolean forceAccess) throws IllegalAccessException Reads the namedField. Superclasses will be considered.- Parameters:
target- the object to reflect, must not benullfieldName- the field name to obtainforceAccess- whether to break scope restrictions using theAccessibleObject.setAccessible(boolean)method.falsewill only matchpublicfields.- Returns:
- the field value
- Throws:
NullPointerException- iftargetisnullIllegalArgumentException- if the field name isnull, blank, empty, or could not be foundIllegalAccessException- if the named field is not made accessible
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readStaticField
Reads the namedpublic staticField. Superclasses will be considered.- Parameters:
cls- theClassto reflect, must not benullfieldName- the field name to obtain- Returns:
- the value of the field
- Throws:
NullPointerException- if the class isnull, or the field could not be foundIllegalArgumentException- if the field name isnull, blank or empty, or is notstaticIllegalAccessException- if the field is not accessible
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readStaticField
public static Object readStaticField(Class<?> cls, String fieldName, boolean forceAccess) throws IllegalAccessException Reads the namedstaticField. Superclasses will be considered.- Parameters:
cls- theClassto reflect, must not benullfieldName- the field name to obtainforceAccess- whether to break scope restrictions using theAccessibleObject.setAccessible(boolean)method.falsewill only matchpublicfields.- Returns:
- the Field object
- Throws:
NullPointerException- if the class isnull, or the field could not be foundIllegalArgumentException- if the field name isnull, blank or empty, or is notstaticIllegalAccessException- if the field is not made accessible
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readStaticField
Reads an accessiblestaticField.- Parameters:
field- to read- Returns:
- the field value
- Throws:
NullPointerException- if the field isnullIllegalArgumentException- if the field is notstaticIllegalAccessException- if the field is not accessible
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readStaticField
public static Object readStaticField(Field field, boolean forceAccess) throws IllegalAccessException Reads a staticField.- Parameters:
field- to readforceAccess- whether to break scope restrictions using theAccessibleObject.setAccessible(boolean)method.- Returns:
- the field value
- Throws:
NullPointerException- if the field isnullIllegalArgumentException- if the field is notstaticIllegalAccessException- if the field is not made accessible
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removeFinalModifier
Removes the final modifier from aField.- Parameters:
field- to remove the final modifier- Throws:
NullPointerException- if the field isnull- Since:
- 3.2
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removeFinalModifier
Deprecated.As of Java 12, we can no longer drop thefinalmodifier, thus rendering this method obsolete. The JDK discussion about this change can be found here: https://mail.openjdk.java.net/pipermail/core-libs-dev/2018-November/056486.htmlRemoves the final modifier from aField.- Parameters:
field- to remove the final modifierforceAccess- whether to break scope restrictions using theAccessibleObject.setAccessible(boolean)method.falsewill only matchpublicfields.- Throws:
NullPointerException- if the field isnull- Since:
- 3.3
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writeDeclaredField
public static void writeDeclaredField(Object target, String fieldName, Object value) throws IllegalAccessException Writes apublicField. Only the specified class will be considered.- Parameters:
target- the object to reflect, must not benullfieldName- the field name to obtainvalue- to set- Throws:
NullPointerException- iftargetisnullIllegalArgumentException- iffieldNameisnull, blank or empty, or could not be found, orvalueis not assignableIllegalAccessException- if the field is not made accessible
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writeDeclaredField
public static void writeDeclaredField(Object target, String fieldName, Object value, boolean forceAccess) throws IllegalAccessException Writes apublicField. Only the specified class will be considered.- Parameters:
target- the object to reflect, must not benullfieldName- the field name to obtainvalue- to setforceAccess- whether to break scope restrictions using theAccessibleObject.setAccessible(boolean)method.falsewill only matchpublicfields.- Throws:
IllegalArgumentException- iffieldNameisnull, blank or empty, or could not be found, orvalueis not assignableIllegalAccessException- if the field is not made accessible
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writeDeclaredStaticField
public static void writeDeclaredStaticField(Class<?> cls, String fieldName, Object value) throws IllegalAccessException Writes a namedpublic staticField. Only the specified class will be considered.- Parameters:
cls-Classon which the field is to be foundfieldName- to writevalue- to set- Throws:
NullPointerException- ifclsisnullor the field cannot be locatedIllegalArgumentException- if the field name isnull, blank, empty, notstatic, orvalueis not assignableIllegalAccessException- if the field is notpublicor isfinal
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writeDeclaredStaticField
public static void writeDeclaredStaticField(Class<?> cls, String fieldName, Object value, boolean forceAccess) throws IllegalAccessException Writes a namedstaticField. Only the specified class will be considered.- Parameters:
cls-Classon which the field is to be foundfieldName- to writevalue- to setforceAccess- whether to break scope restrictions using theAccessibleObject#setAccessible(boolean)method.falsewill only matchpublicfields.- Throws:
NullPointerException- ifclsisnullor the field cannot be locatedIllegalArgumentException- if the field name isnull, blank, empty, notstatic, orvalueis not assignableIllegalAccessException- if the field is not made accessible or isfinal
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writeField
public static void writeField(Field field, Object target, Object value) throws IllegalAccessException Writes an accessibleField.- Parameters:
field- to writetarget- the object to call on, may benullforstaticfieldsvalue- to set- Throws:
NullPointerException- if the field isnullIllegalArgumentException- ifvalueis not assignableIllegalAccessException- if the field is not accessible or isfinal
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writeField
public static void writeField(Field field, Object target, Object value, boolean forceAccess) throws IllegalAccessException Writes aField.- Parameters:
field- to writetarget- the object to call on, may benullforstaticfieldsvalue- to setforceAccess- whether to break scope restrictions using theAccessibleObject.setAccessible(boolean)method.falsewill only matchpublicfields.- Throws:
NullPointerException- if the field isnullIllegalArgumentException- ifvalueis not assignableIllegalAccessException- if the field is not made accessible or isfinal
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writeField
public static void writeField(Object target, String fieldName, Object value) throws IllegalAccessException Writes apublicField. Superclasses will be considered.- Parameters:
target- the object to reflect, must not benullfieldName- the field name to obtainvalue- to set- Throws:
NullPointerException- iftargetisnullIllegalArgumentException- iffieldNameisnull, blank, empty, or could not be found, orvalueis not assignableIllegalAccessException- if the field is not accessible
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writeField
public static void writeField(Object target, String fieldName, Object value, boolean forceAccess) throws IllegalAccessException Writes aField. Superclasses will be considered.- Parameters:
target- the object to reflect, must not benullfieldName- the field name to obtainvalue- to setforceAccess- whether to break scope restrictions using theAccessibleObject.setAccessible(boolean)method.falsewill only matchpublicfields.- Throws:
NullPointerException- iftargetisnullIllegalArgumentException- iffieldNameisnull, blank, empty, or could not be found, orvalueis not assignableIllegalAccessException- if the field is not made accessible
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writeStaticField
public static void writeStaticField(Class<?> cls, String fieldName, Object value) throws IllegalAccessException Writes a namedpublic staticField. Superclasses will be considered.- Parameters:
cls-Classon which the field is to be foundfieldName- to writevalue- to set- Throws:
NullPointerException- iftargetisnullIllegalArgumentException- iffieldNameisnull, blank or empty, the field cannot be located or is notstatic, orvalueis not assignableIllegalAccessException- if the field is notpublicor isfinal
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writeStaticField
public static void writeStaticField(Class<?> cls, String fieldName, Object value, boolean forceAccess) throws IllegalAccessException Writes a namedstaticField. Superclasses will be considered.- Parameters:
cls-Classon which the field is to be foundfieldName- to writevalue- to setforceAccess- whether to break scope restrictions using theAccessibleObject.setAccessible(boolean)method.falsewill only matchpublicfields.- Throws:
NullPointerException- ifclsisnullor the field cannot be locatedIllegalArgumentException- iffieldNameisnull, blank or empty, the field notstatic, orvalueis not assignableIllegalAccessException- if the field is not made accessible or isfinal
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writeStaticField
Writes apublic staticField.- Parameters:
field- to writevalue- to set- Throws:
NullPointerException- if the field isnullIllegalArgumentException- if the field is notstatic, orvalueis not assignableIllegalAccessException- if the field is notpublicor isfinal
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writeStaticField
public static void writeStaticField(Field field, Object value, boolean forceAccess) throws IllegalAccessException Writes a staticField.- Parameters:
field- to writevalue- to setforceAccess- whether to break scope restrictions using theAccessibleObject.setAccessible(boolean)method.falsewill only matchpublicfields.- Throws:
NullPointerException- if the field isnullIllegalArgumentException- if the field is notstatic, orvalueis not assignableIllegalAccessException- if the field is not made accessible or isfinal
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