com.github.panxiaole.polestar.common.utils.ReflectUtil Maven / Gradle / Ivy
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package com.github.panxiaole.polestar.common.utils;
import org.apache.commons.lang3.Validate;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.lang.reflect.*;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
/**
* 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 panxiaole
*/
@SuppressWarnings("rawtypes")
public class ReflectUtil {
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(ReflectUtil.class);
/**
* 调用Getter方法.
* 支持多级，如：对象名.对象名.方法
*/
@SuppressWarnings("unchecked")
public static E invokeGetter(Object obj, String propertyName) {
Object object = obj;
for (String name : StringUtil.split(propertyName, ".")) {
String getterMethodName = GETTER_PREFIX + StringUtil.capitalize(name);
object = invokeMethod(object, getterMethodName, new Class[]{}, new Object[]{});
}
return (E) object;
}
/**
* 直接读取对象属性值, 无视private/protected修饰符, 不经过getter函数.
*/
@SuppressWarnings("unchecked")
public static E getFieldValue(final Object obj, final String fieldName) {
Field field = getAccessibleField(obj, fieldName);
if (field == null) {
logger.debug("在 [" + obj.getClass() + "] 中，没有找到 [" + fieldName + "] 字段 ");
return null;
}
E result = null;
try {
result = (E) 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 E value) {
Field field = getAccessibleField(obj, fieldName);
if (field == null) {
logger.debug("在 [" + obj.getClass() + "] 中，没有找到 [" + fieldName + "] 字段 ");
return;
}
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，
*/
@SuppressWarnings("unchecked")
public static E invokeMethod(final Object obj, final String methodName, final Class[] parameterTypes,
final Object[] args) {
if (obj == null || methodName == null) {
return null;
}
Method method = getAccessibleMethod(obj, methodName, parameterTypes);
if (method == null) {
logger.debug("在 [" + obj.getClass() + "] 中，没有找到 [" + methodName + "] 方法 ");
return null;
}
try {
return (E) method.invoke(obj, args);
} catch (Exception e) {
String msg = "method: " + method + ", obj: " + obj + ", args: " + args + "";
throw convertReflectionExceptionToUnchecked(msg, 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) {
// 为空不报错。直接返回 null
if (obj == null) {
return 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) {
// 为空不报错。直接返回 null
if (obj == null) {
return 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, int argsNum) {
// 为空不报错。直接返回 null
if (obj == null) {
return 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) && method.getParameterTypes().length == argsNum) {
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
*
* @param clazz The class to introspect
* @return the first generic declaration, or Object.class if cannot be determined
*/
@SuppressWarnings("unchecked")
public static Class getClassGenericType(final Class clazz) {
return getClassGenericType(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
*
* @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 getClassGenericType(final Class clazz, final int index) {
Type genType = clazz.getGenericSuperclass();
if (!(genType instanceof ParameterizedType)) {
logger.debug(clazz.getSimpleName() + "'s superclass not ParameterizedType");
return Object.class;
}
Type[] params = ((ParameterizedType) genType).getActualTypeArguments();
if (index >= params.length || index < 0) {
logger.debug("Index: " + index + ", Size of " + clazz.getSimpleName() + "'s Parameterized Type: "
+ params.length);
return Object.class;
}
if (!(params[index] instanceof Class)) {
logger.debug(clazz.getSimpleName() + " not set the actual class on superclass generic parameter");
return Object.class;
}
return (Class) params[index];
}
public static Class getUserClass(Object instance) {
if (instance == null) {
throw new RuntimeException("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(String msg, Exception e) {
if (e instanceof IllegalAccessException || e instanceof IllegalArgumentException
|| e instanceof NoSuchMethodException) {
return new IllegalArgumentException(msg, e);
} else if (e instanceof InvocationTargetException) {
return new RuntimeException(msg, ((InvocationTargetException) e).getTargetException());
}
return new RuntimeException(msg, e);
}
/**
* 获取类名
*
* @param clazz
* @return
*/
public static String getEntityName(Class clazz) {
return clazz.getSimpleName();
}
/**
* 获取实体类的所有字段(包含所有父类)
*
* @param clazz
* @return
*/
public static List getAllFields(Class clazz) {
List fields = new ArrayList<>();
// 当父类为null的时候说明到达了最上层的父类
while (clazz != null) {
fields.addAll(Arrays.asList(clazz.getDeclaredFields()));
// 得到父类,然后赋给自己
clazz = clazz.getSuperclass();
}
return fields;
}
}