Java 反射工具类详解编程语言

package com.su.dolphin.utils; 
import java.lang.reflect.Array; 
import java.lang.reflect.Constructor; 
import java.lang.reflect.Field; 
import java.lang.reflect.InvocationTargetException; 
import java.lang.reflect.Method; 
/** 
*  
* @className: ReflectionUtil 
* @description: 反射工具类 
* @author: gaoshuai 
* @date: 2015年8月5日 下午4:51:49 
*/ 
public class ReflectionUtil 
{ 
/** 
*  
* @title: setField 
* @description: 设置某个成员遍历的值 
* @param owner 
* @param fieldName 
* @param value 
* @throws Exception 
* @return: void 
*/ 
public static void setField(Object owner, String fieldName, Object value) throws Exception { 
Class<?> ownerClass = owner.getClass(); 
Field field = ownerClass.getDeclaredField(fieldName); 
field.setAccessible(true); 
field.set(owner, value); 
} 
/** 
*  
* @title: setFieldAll 
* @description: 可以设置父类的field的值 
* @param owner 
* @param fieldName 
* @param value 
* @throws Exception 
* @return: void 
*/ 
public static void setFieldAll(Object owner, String fieldName, Object value) throws Exception { 
Class<?> ownerClass = owner.getClass(); 
Field field = null; 
for (Class<?> clazz = ownerClass; clazz != Object.class; clazz = clazz.getSuperclass()) { 
try { 
field = clazz.getDeclaredField(fieldName); 
LogUtil.d(field + " find : in " + clazz.getName()); 
break; 
} 
catch (Exception e) { 
LogUtil.d(fieldName + " not find in " + clazz.getName()); 
} 
} 
field.setAccessible(true); 
field.set(owner, value); 
} 
/** 
* 得到某个对象的公共属性 
*  
* @param owner 
*            , fieldName 
* @return 该属性对象 
* @throws Exception 
*  
*/ 
public static Object getField(Object owner, String fieldName) throws Exception { 
Class<?> ownerClass = owner.getClass(); 
Field field = ownerClass.getField(fieldName); 
Object property = field.get(owner); 
return property; 
} 
/** 
* 得到某类的静态公共属性 
*  
* @param className 
*            类名 
* @param fieldName 
*            属性名 
* @return 该属性对象 
* @throws Exception 
*/ 
public static Object getStaticField(String className, String fieldName) throws Exception { 
Class<?> ownerClass = Class.forName(className); 
Field field = ownerClass.getField(fieldName); 
Object property = field.get(ownerClass); 
return property; 
} 
/** 
* 执行某对象方法 
*  
* @param owner 
*            对象 
* @param methodName 
*            方法名 
* @param args 
*            参数 
* @return 方法返回值 
* @throws Exception 
*/ 
public static Object invokeMethod(Object owner, String methodName, Object... args) throws Exception { 
Class<?> ownerClass = owner.getClass(); 
Class<?>[] argsClass = new Class[args.length]; 
for (int i = 0, j = args.length; i < j; i++) { 
if (args[i].getClass() == Integer.class) { //一般的函数都是 int 而不是Integer 
argsClass[i] = int.class; 
} 
else if (args[i].getClass() == Float.class) { //一般的函数都是 int 而不是Integer 
argsClass[i] = float.class; 
} 
else if (args[i].getClass() == Double.class) { //一般的函数都是 int 而不是Integer 
argsClass[i] = double.class; 
} 
else { 
argsClass[i] = args[i].getClass(); 
} 
} 
Method method = ownerClass.getDeclaredMethod(methodName, argsClass); 
method.setAccessible(true); 
return method.invoke(owner, args); 
} 
/** 
*  
* @title: invokeMethodAll 
* @description: 调用所有的函数, 包括父类的所有函数 
* @param owner 
* @param methodName 
* @param args 
* @return 
* @throws Exception 
* @return: Object 
*/ 
public static Object invokeMethodAll(Object owner, String methodName, Object... args) throws Exception { 
Class<?> ownerClass = owner.getClass(); 
Class<?>[] argsClass = new Class[args.length]; 
for (int i = 0, j = args.length; i < j; i++) { 
if (args[i].getClass() == Integer.class) { //一般的函数都是 int 而不是Integer 
argsClass[i] = int.class; 
} 
else if (args[i].getClass() == Float.class) { //一般的函数都是 int 而不是Integer 
argsClass[i] = float.class; 
} 
else if (args[i].getClass() == Double.class) { //一般的函数都是 int 而不是Integer 
argsClass[i] = double.class; 
} 
else { 
argsClass[i] = args[i].getClass(); 
} 
} 
Method method = null; 
for (Class<?> clazz = ownerClass; clazz != Object.class; clazz = clazz.getSuperclass()) { 
try { 
method = clazz.getDeclaredMethod(methodName, argsClass); 
LogUtil.d(method + " find : in " + clazz.getName()); 
return method; 
} 
catch (Exception e) { 
//e.printStackTrace(); 
LogUtil.d(methodName + " not find in " + clazz.getName()); 
} 
} 
method.setAccessible(true); 
return method.invoke(owner, args); 
} 
/** 
* 执行某类的静态方法 
*  
* @param className 
*            类名 
* @param methodName 
*            方法名 
* @param args 
*            参数数组 
* @return 执行方法返回的结果 
* @throws Exception 
*/ 
public static Object invokeStaticMethod(String className, String methodName, Object... args) throws Exception { 
Class<?> ownerClass = Class.forName(className); 
Class<?>[] argsClass = new Class[args.length]; 
for (int i = 0, j = args.length; i < j; i++) { 
argsClass[i] = args[i].getClass(); 
} 
Method method = ownerClass.getMethod(methodName, argsClass); 
method.setAccessible(true); 
return method.invoke(null, args); 
} 
/** 
* 新建实例 
*  
* @param className 
*            类名 
* @param args 
*            构造函数的参数 如果无构造参数，args 填写为 null 
* @return 新建的实例 
* @throws Exception 
*/ 
public static Object newInstance(String className, Object[] args) throws NoSuchMethodException, SecurityException, ClassNotFoundException, InstantiationException, IllegalAccessException, IllegalArgumentException, InvocationTargetException { 
return newInstance(className, args, null); 
} 
/** 
* 新建实例 
*  
* @param className 
*            类名 
* @param args 
*            构造函数的参数 如果无构造参数，args 填写为 null 
* @return 新建的实例 
* @throws Exception 
*/ 
public static Object newInstance(String className, Object[] args, Class<?>[] argsType) throws NoSuchMethodException, SecurityException, ClassNotFoundException, InstantiationException, IllegalAccessException, IllegalArgumentException, InvocationTargetException { 
Class<?> newoneClass = Class.forName(className); 
if (args == null) { 
return newoneClass.newInstance(); 
} 
else { 
Constructor<?> cons; 
if (argsType == null) { 
Class<?>[] argsClass = new Class[args.length]; 
for (int i = 0, j = args.length; i < j; i++) { 
argsClass[i] = args[i].getClass(); 
} 
cons = newoneClass.getConstructor(argsClass); 
} 
else { 
cons = newoneClass.getConstructor(argsType); 
} 
return cons.newInstance(args); 
} 
} 
/** 
* 是不是某个类的实例 
*  
* @param obj 
*            实例 
* @param cls 
*            类 
* @return 如果 obj 是此类的实例，则返回 true 
*/ 
public static boolean isInstance(Object obj, Class<?> cls) { 
return cls.isInstance(obj); 
} 
/** 
* 得到数组中的某个元素 
*  
* @param array 
*            数组 
* @param index 
*            索引 
* @return 返回指定数组对象中索引组件的值 
*/ 
public static Object getItemInArray(Object array, int index) { 
return Array.get(array, index); 
} 
/** 
*  
* @title: GetClassListByPackage 
* @description: 获取包下的所有Class 
* @param pPackage 
* @return 
* @return: Class<?> 
*/ 
public static Class<?> getClassListByPackage(String pPackage) { 
Package _Package = Package.getPackage(pPackage); 
Class<?> _List = _Package.getClass(); 
return _List; 
} 
}

注意: 

1.调用getMethods方法输出的是自身的public方法和父类Object的public方法。调用getDeclaredMethods方法输出的是自身的public、protected、private方法。

2.如果想获取父类的私有函数

public static Method getDeclaredMethod(Object object, String methodName, Class<?> ... parameterTypes){   
Method method = null ;   
for(Class<?> clazz = object.getClass() ; clazz != Object.class ; clazz = clazz.getSuperclass()) {   
try {   
method = clazz.getDeclaredMethod(methodName, parameterTypes) ;   
return method ;   
} catch (Exception e) {   
}   
}   
return null;   
}

来自：http://my.oschina.net/sfshine/blog/488280