程序包 org.apache.velocity.tools

类 ClassUtils

java.lang.Object

org.apache.velocity.tools.ClassUtils

public class ClassUtils
extends Object

Repository for common class and reflection methods.

版本:

$Id: ClassUtils.java 511959 2007-02-26 19:24:39Z nbubna $

作者:

Nathan Bubna

方法概要

修饰符和类型	方法	说明
static Method	findDeclaredMethod(Class clazz, String name, Class... params)	Find a declared method in a class.
static Method	findFactoryMethod(Class factory, Class target)	Given a factory class and a target class, search for the following methods:
static Method	findGetter(String getterName, Class clazz)
static Method	findGetter(String getterName, Class clazz, boolean mandatory)
static Method	findMethod(Class clazz, String name, Class... params)	Find a callable method in a class
static Method	findSetter(String setterName, Class clazz)
static Method	findSetter(String setterName, Class clazz, Predicate<Class> argumentClassFilter)
static Method	findSetter(String setterName, Class clazz, Predicate<Class> argumentClassFilter, boolean mandatory)
static Class	getClass(String name)	Load a class with a given name.
static Object	getFieldValue(Class clazz, String fieldname)	Given a class and a static field name, get the field value.
static Object	getFieldValue(String fieldPath)	Given a static field path, aka classname.field, get the field value.
static Object	getInstance(String classname)	Get an instance of a named class.
static Iterator	getIterator(Object obj)	Retrieves an Iterator from or creates and Iterator for the specified object.
static URL	getResource(String name, Object caller)	Load a given resource.
static InputStream	getResourceAsStream(String name, Object caller)	This is a convenience method to load a resource as a stream.
static List<URL>	getResources(String name, Object caller)	Load all resources with the specified name.

从类继承的方法 java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

方法详细资料

getClass

public static Class getClass(String name)
                      throws ClassNotFoundException

Load a class with a given name. It will try to load the class in the following order:

• From Thread.currentThread().getContextClassLoader()
• Using the basic Class.forName(java.lang.String)
• From ClassUtils.class.getClassLoader()

参数:

name - Fully qualified class name to be loaded

返回:

Class object

抛出:

ClassNotFoundException - if the class cannot be found

getInstance

public static Object getInstance(String classname)
                          throws ClassNotFoundException,
IllegalAccessException,
InstantiationException

Get an instance of a named class.

参数:

classname - class name

返回:

new class instance

抛出:

ClassNotFoundException - if class is not found

IllegalAccessException - if not granted

InstantiationException - if instance creation throwed

getResources

public static List<URL> getResources(String name,
 Object caller)

Load all resources with the specified name. If none are found, we prepend the name with '/' and try again. This will attempt to load the resources from the following methods (in order):

• Thread.currentThread().getContextClassLoader().getResources(name)
• ClassUtils.class.getClassLoader().getResources(name)
• ClassUtils.class.getResource(name)
• getCallerLoader(Object caller).getResources(name)
• caller.getClass().getResource(name)

参数:

name - The name of the resources to load

caller - The instance or Class calling this method

返回:

the list of found resources

getResource

public static URL getResource(String name,
 Object caller)

Load a given resource. This method will try to load the resource using the following methods (in order):

• Thread.currentThread().getContextClassLoader().getResource(name)
• ClassUtils.class.getClassLoader().getResource(name)
• ClassUtils.class.getResource(name)
• caller.getClass().getResource(name) or, if caller is a Class, caller.getResource(name)

参数:

name - The name of the resource to load

caller - The instance or Class calling this method

返回:

the found URL, or null if not found

getResourceAsStream

public static InputStream getResourceAsStream(String name,
 Object caller)

This is a convenience method to load a resource as a stream. The algorithm used to find the resource is given in getResource()

参数:

name - The name of the resource to load

caller - The instance or Class calling this method

返回:

the resource input stream or null if not found

findMethod

public static Method findMethod(Class clazz,
 String name,
 Class... params)
                         throws SecurityException

Find a callable method in a class

参数:

clazz - target class

name - method name

params - method arguments classes

返回:

method object

抛出:

SecurityException - if not granted

findDeclaredMethod

public static Method findDeclaredMethod(Class clazz,
 String name,
 Class... params)
                                 throws SecurityException

Find a declared method in a class. It will be made accessible if needed and allowed.

参数:

clazz - target class

name - method name

params - method arguments classes

返回:

抛出:

SecurityException - if not allowed

getFieldValue

public static Object getFieldValue(String fieldPath)
                            throws ClassNotFoundException,
NoSuchFieldException,
SecurityException,
IllegalAccessException

Given a static field path, aka classname.field, get the field value.

参数:

fieldPath - field path

返回:

field value

抛出:

ClassNotFoundException - if class hasn't been found

NoSuchFieldException - if field hasn't been found

SecurityException - if not granted

IllegalAccessException - if field is not accessible

getFieldValue

public static Object getFieldValue(Class clazz,
 String fieldname)
                            throws NoSuchFieldException,
SecurityException,
IllegalAccessException

Given a class and a static field name, get the field value.

参数:

clazz - target class

fieldname - field name

返回:

field value

抛出:

NoSuchFieldException - if field hasn't been found

SecurityException - if not granted

IllegalAccessException - if field is not accessible

getIterator

public static Iterator getIterator(Object obj)
                            throws NoSuchMethodException,
IllegalAccessException,
InvocationTargetException

Retrieves an Iterator from or creates and Iterator for the specified object. This method is almost entirely copied from Engine's UberspectImpl class.

参数:

obj - the target obj

返回:

an iterator over the content of obj, or null if not found

抛出:

NoSuchMethodException - if no iterator() method

IllegalAccessException - if iterator() method not callable

InvocationTargetException - if iterator() method throwed

findFactoryMethod

public static Method findFactoryMethod(Class factory,
 Class target)

Given a factory class and a target class, search for the following methods:

• createTargetClassname(),
• newTargetClassname(), or
• getTargetClassname().

参数:

factory - factory class

target - target class

返回:

first factory method found, or null otherwise

findGetter

public static Method findGetter(String getterName,
 Class clazz)
                         throws NoSuchMethodException

抛出:

NoSuchMethodException

findGetter

public static Method findGetter(String getterName,
 Class clazz,
 boolean mandatory)
                         throws NoSuchMethodException

抛出:

NoSuchMethodException

findSetter

public static Method findSetter(String setterName,
 Class clazz)
                         throws NoSuchMethodException

抛出:

NoSuchMethodException

findSetter

public static Method findSetter(String setterName,
 Class clazz,
 Predicate<Class> argumentClassFilter)
                         throws NoSuchMethodException

抛出:

NoSuchMethodException

findSetter

public static Method findSetter(String setterName,
 Class clazz,
 Predicate<Class> argumentClassFilter,
 boolean mandatory)
                         throws NoSuchMethodException

抛出:

NoSuchMethodException