反射工具类

public class Reflections {
   
   private static final String SETTER_PREFIX = "set";

   private static final String GETTER_PREFIX = "get";

   private static final String CGLIB_CLASS_SEPARATOR = "$$";
   
   private static Logger logger = LoggerFactory.getLogger(Reflections.class);

   /**
    * 调用Getter方法.
    * 支持多级，如：对象名.对象名.方法
    */
   public static Object invokeGetter(Object obj, String propertyName) {
      Object object = obj;
      for (String name : StringUtils.split(propertyName, ".")){
         String getterMethodName = GETTER_PREFIX + StringUtils.capitalize(name);
         object = invokeMethod(object, getterMethodName, new Class[] {}, new Object[] {});
      }
      return object;
   }

   /**
    * 调用Setter方法, 仅匹配方法名。
    * 支持多级，如：对象名.对象名.方法
    */
   public static void invokeSetter(Object obj, String propertyName, Object value) {
      Object object = obj;
      String[] names = StringUtils.split(propertyName, ".");
      for (int i=0; i<names.length; i++){
         if(i<names.length-1){
            String getterMethodName = GETTER_PREFIX + StringUtils.capitalize(names[i]);
            object = invokeMethod(object, getterMethodName, new Class[] {}, new Object[] {});
         }else{
            String setterMethodName = SETTER_PREFIX + StringUtils.capitalize(names[i]);
            invokeMethodByName(object, setterMethodName, new Object[] { value });
         }
      }
   }

   /**
    * 直接读取对象属性值, 无视private/protected修饰符, 不经过getter函数.
    */
   public static Object getFieldValue(final Object obj, final String fieldName) {
      Field field = getAccessibleField(obj, fieldName);

      if (field == null) {
         throw new IllegalArgumentException("Could not find field [" + fieldName + "] on target [" + obj + "]");
      }

      Object result = null;
      try {
         result = field.get(obj);
      } catch (IllegalAccessException e) {
         logger.error("不可能抛出的异常{}", e.getMessage());
      }
      return result;
   }

   /**
    * 直接设置对象属性值, 无视private/protected修饰符, 不经过setter函数.
    */
   public static void setFieldValue(final Object obj, final String fieldName, final Object value) {
      Field field = getAccessibleField(obj, fieldName);

      if (field == null) {
         throw new IllegalArgumentException("Could not find field [" + fieldName + "] on target [" + obj + "]");
      }

      try {
         field.set(obj, value);
      } catch (IllegalAccessException e) {
         logger.error("不可能抛出的异常:{}", e.getMessage());
      }
   }

   /**
    * 直接调用对象方法, 无视private/protected修饰符.
    * 用于一次性调用的情况，否则应使用getAccessibleMethod()函数获得Method后反复调用.
    * 同时匹配方法名+参数类型，
    */
   public static Object invokeMethod(final Object obj, final String methodName, final Class<?>[] parameterTypes,
         final Object[] args) {
      Method method = getAccessibleMethod(obj, methodName, parameterTypes);
      if (method == null) {
         throw new IllegalArgumentException("Could not find method [" + methodName + "] on target [" + obj + "]");
      }

      try {
         return method.invoke(obj, args);
      } catch (Exception e) {
         throw convertReflectionExceptionToUnchecked(e);
      }
   }

   /**
    * 直接调用对象方法, 无视private/protected修饰符，
    * 用于一次性调用的情况，否则应使用getAccessibleMethodByName()函数获得Method后反复调用.
    * 只匹配函数名，如果有多个同名函数调用第一个。
    */
   public static Object invokeMethodByName(final Object obj, final String methodName, final Object[] args) {
      Method method = getAccessibleMethodByName(obj, methodName);
      if (method == null) {
         throw new IllegalArgumentException("Could not find method [" + methodName + "] on target [" + obj + "]");
      }

      try {
         return method.invoke(obj, args);
      } catch (Exception e) {
         throw convertReflectionExceptionToUnchecked(e);
      }
   }

   /**
    * 循环向上转型, 获取对象的DeclaredField, 并强制设置为可访问.
    * 
    * 如向上转型到Object仍无法找到, 返回null.
    */
   public static Field getAccessibleField(final Object obj, final String fieldName) {
      Validate.notNull(obj, "object can't be null");
      Validate.notBlank(fieldName, "fieldName can't be blank");
      for (Class<?> superClass = obj.getClass(); superClass != Object.class; superClass = superClass.getSuperclass()) {
         try {
            Field field = superClass.getDeclaredField(fieldName);
            makeAccessible(field);
            return field;
         } catch (NoSuchFieldException e) {//NOSONAR
            // Field不在当前类定义,继续向上转型
            continue;// new add
         }
      }
      return null;
   }

   /**
    * 循环向上转型, 获取对象的DeclaredMethod,并强制设置为可访问.
    * 如向上转型到Object仍无法找到, 返回null.
    * 匹配函数名+参数类型。
    * 
    * 用于方法需要被多次调用的情况. 先使用本函数先取得Method,然后调用Method.invoke(Object obj, Object... args)
    */
   public static Method getAccessibleMethod(final Object obj, final String methodName,
         final Class<?>... parameterTypes) {
      Validate.notNull(obj, "object can't be null");
      Validate.notBlank(methodName, "methodName can't be blank");

      for (Class<?> searchType = obj.getClass(); searchType != Object.class; searchType = searchType.getSuperclass()) {
         try {
            Method method = searchType.getDeclaredMethod(methodName, parameterTypes);
            makeAccessible(method);
            return method;
         } catch (NoSuchMethodException e) {
            // Method不在当前类定义,继续向上转型
            continue;// new add
         }
      }
      return null;
   }

   /**
    * 循环向上转型, 获取对象的DeclaredMethod,并强制设置为可访问.
    * 如向上转型到Object仍无法找到, 返回null.
    * 只匹配函数名。
    * 
    * 用于方法需要被多次调用的情况. 先使用本函数先取得Method,然后调用Method.invoke(Object obj, Object... args)
    */
   public static Method getAccessibleMethodByName(final Object obj, final String methodName) {
      Validate.notNull(obj, "object can't be null");
      Validate.notBlank(methodName, "methodName can't be blank");

      for (Class<?> searchType = obj.getClass(); searchType != Object.class; searchType = searchType.getSuperclass()) {
         Method[] methods = searchType.getDeclaredMethods();
         for (Method method : methods) {
            if (method.getName().equals(methodName)) {
               makeAccessible(method);
               return method;
            }
         }
      }
      return null;
   }

   /**
    * 改变private/protected的方法为public，尽量不调用实际改动的语句，避免JDK的SecurityManager抱怨。
    */
   public static void makeAccessible(Method method) {
      if ((!Modifier.isPublic(method.getModifiers()) || !Modifier.isPublic(method.getDeclaringClass().getModifiers()))
            && !method.isAccessible()) {
         method.setAccessible(true);
      }
   }

   /**
    * 改变private/protected的成员变量为public，尽量不调用实际改动的语句，避免JDK的SecurityManager抱怨。
    */
   public static void makeAccessible(Field field) {
      if ((!Modifier.isPublic(field.getModifiers()) || !Modifier.isPublic(field.getDeclaringClass().getModifiers()) || Modifier
            .isFinal(field.getModifiers())) && !field.isAccessible()) {
         field.setAccessible(true);      }   }   



/**
    * 通过反射, 获得Class定义中声明的泛型参数的类型, 注意泛型必须定义在父类处
* 如无法找到, 返回Object.class.
    * eg.
    * public UserDao extends HibernateDao<User>
    *
    * @param clazz The class to introspect
    * @return the first generic declaration, or Object.class if cannot be determined
    */
@SuppressWarnings("unchecked")   
public static <T> Class<T> getClassGenricType(final Class clazz) {      
return getClassGenricType(clazz, 0);   }   


/**
    * 通过反射, 获得Class定义中声明的父类的泛型参数的类型.
    * 如无法找到, 返回Object.class.
    * 
    * 如public UserDao extends HibernateDao<User,Long>
    *
    * @param clazz clazz The class to introspect
    * @param index the Index of the generic ddeclaration,start from 0.
    * @return the index generic declaration, or Object.class if cannot be determined
    */
public static Class getClassGenricType(final Class clazz, final int index) {      

Type genType = clazz.getGenericSuperclass();      

if (!(genType instanceof ParameterizedType)) {         
logger.warn(clazz.getSimpleName() + "'s superclass not ParameterizedType");         
return Object.class;      }      


Type[] params = ((ParameterizedType) genType).getActualTypeArguments();      

if (index >= params.length || index < 0) {         
logger.warn("Index: " + index + ", Size of " + clazz.getSimpleName() + "'s Parameterized Type: "
               + params.length);         
return Object.class;      }      

if (!(params[index] instanceof Class)) {         
logger.warn(clazz.getSimpleName() + " not set the actual class on superclass generic parameter");         
return Object.class;      }      


return (Class) params[index];   }      


public static Class<?> getUserClass(Object instance) {      
Assert.notNull(instance, "Instance must not be null");      
Class clazz = instance.getClass();      
if (clazz != null && clazz.getName().contains(CGLIB_CLASS_SEPARATOR)) {         
Class<?> superClass = clazz.getSuperclass();         
if (superClass != null && !Object.class.equals(superClass)) {            
return superClass;         }      }      


return clazz;   }      



/**
    * 将反射时的checked exception转换为unchecked exception.
    */
public static RuntimeException convertReflectionExceptionToUnchecked(Exception e) {      
if (e instanceof IllegalAccessException || e instanceof IllegalArgumentException
            || e instanceof NoSuchMethodException) {         
return new IllegalArgumentException(e);      } 
else if (e instanceof InvocationTargetException) {         
return new RuntimeException(((InvocationTargetException) e).getTargetException());      } 
else if (e instanceof RuntimeException) {         
return (RuntimeException) e;      }      

return new RuntimeException("Unexpected Checked Exception.", e);   }}