com.feingto.cloud.kit.reflection.ReflectionKit Maven / Gradle / Ivy
package com.feingto.cloud.kit.reflection;
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.lang3.StringUtils;
import org.springframework.util.Assert;
import java.lang.reflect.*;
import java.util.Objects;
/**
* 反射工具类.
*
* 提供调用getter/setter方法, 访问私有变量, 调用私有方法, 获取泛型类型Class, 被AOP过的真实类等工具函数.
*
* @author longfei
*/
@Slf4j
@SuppressWarnings("unchecked")
public class ReflectionKit {
private static final String SETTER_PREFIX = "set";
private static final String GETTER_PREFIX = "get";
private static final String CGLIB_CLASS_SEPARATOR = "$$";
/**
* 通过类名得到类对象
*/
public static Class forName(String className) {
try {
return Class.forName(className);
} catch (ClassNotFoundException e) {
log.error("类不存在异常:{}", e.getMessage());
return null;
}
}
/**
* 调用Getter方法
*/
public static Object invokeGetter(Object obj, String propertyName) {
String getterMethodName = GETTER_PREFIX + StringUtils.capitalize(propertyName);
return invokeMethod(obj, getterMethodName, new Class[]{}, new Object[]{});
}
/**
* 调用Setter方法, 仅匹配方法名
*/
public static void invokeSetter(Object obj, String propertyName, Object value) {
String setterMethodName = SETTER_PREFIX + StringUtils.capitalize(propertyName);
invokeMethodByName(obj, 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 (Objects.isNull(field)) {
//throw new IllegalArgumentException("Could not find field [" + fieldName + "] on target [" + obj + "]");
log.warn("Could not find field [{}] on target [{}]", fieldName, obj);
return null;
}
Object result = null;
try {
result = field.get(obj);
} catch (IllegalAccessException e) {
log.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 (Objects.isNull(field)) {
throw new IllegalArgumentException("Could not find field [" + fieldName + "] on target [" + obj + "]");
}
try {
field.set(obj, value);
} catch (IllegalAccessException e) {
log.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 (Objects.isNull(method)) {
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 (Objects.isNull(method)) {
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) {
Assert.notNull(obj, "object can't be null");
Assert.notNull(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) {
// Field不在当前类定义,继续向上转型
}
}
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) {
Assert.notNull(obj, "object can't be null");
Assert.notNull(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
}
}
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) {
Assert.notNull(obj, "object can't be null");
Assert.notNull(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定义中声明的父类的泛型参数的类型, 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
*
* @param clazz The class to introspect
* @return the first generic declaration, or Object.class if cannot be determined
*/
public static Class 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
* Example public UserDao extends HibernateDao
*
* @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)) {
log.warn(clazz.getSimpleName() + "'s superclass not ParameterizedType");
return Object.class;
}
Type[] params = ((ParameterizedType) genType).getActualTypeArguments();
if (index >= params.length || index < 0) {
log.warn("Index: " + index + ", Size of " + clazz.getSimpleName() + "'s Parameterized Type: " + params.length);
return Object.class;
}
if (!(params[index] instanceof Class)) {
log.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 (Objects.nonNull(clazz) && clazz.getName().contains(CGLIB_CLASS_SEPARATOR)) {
Class superClass = clazz.getSuperclass();
if (Objects.nonNull(superClass) && !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);
}
}