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