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/*******************************************************************************
* Copyright (c) 2017 by JoyLau. All rights reserved
******************************************************************************/
package cn.joylau.commons.utils;
import java.lang.annotation.Annotation;
import java.lang.reflect.Method;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.util.*;
public class ClassUtils {
/**
* 获取一个类的注解,如果未获取到则获取父类
*
* @param clazz 要获取的类
* @param annotation 注解类型
* @param 注解类型泛型
* @return 注解
*/
public static T getAnnotation(Class clazz, Class annotation) {
T ann = clazz.getAnnotation(annotation);
if (ann != null) {
return ann;
} else {
if (clazz.getSuperclass() != Object.class) {
//尝试获取父类
return getAnnotation(clazz.getSuperclass(), annotation);
}
}
return ann;
}
/**
* 获取一个方法的注解,如果未获取则获取父类方法
*
* @param method 要获取的方法
* @param annotation 注解类型
* @param 注解类型泛型
* @return
*/
public static T getAnnotation(Method method, Class annotation) {
T ann = method.getAnnotation(annotation);
if (ann != null) {
return ann;
} else {
Class clazz = method.getDeclaringClass();
Class superClass = clazz.getSuperclass();
if (superClass != Object.class) {
try {
//父类方法
Method suMethod = superClass.getMethod(method.getName(), method.getParameterTypes());
return getAnnotation(suMethod, annotation);
} catch (NoSuchMethodException e) {
return null;
}
}
}
return ann;
}
public static Class getGenericTypeByType(ParameterizedType genType, int index) {
Type[] params = genType.getActualTypeArguments();
if (index >= params.length || index < 0) {
return null;
}
Object res = params[index];
if (res instanceof Class) {
return ((Class) res);
}
if (res instanceof ParameterizedType) {
return (Class) ((ParameterizedType) res).getRawType();
}
return null;
}
/**
* 获取一个类的泛型类型,如果未获取到返回Object.class
*
* @param clazz 要获取的类
* @param index 泛型索引
* @return 泛型
*/
public static Class getGenericType(Class clazz, int index) {
List arrys = new ArrayList<>();
arrys.add(clazz.getGenericSuperclass());
arrys.addAll(Arrays.asList(clazz.getGenericInterfaces()));
return arrys.stream()
.filter(Objects::nonNull)
.map(type -> {
if (clazz != Object.class && !(type instanceof ParameterizedType)) {
return getGenericType(clazz.getSuperclass(), index);
}
return getGenericTypeByType(((ParameterizedType) type), index);
})
.filter(Objects::nonNull)
.filter(res -> res != Object.class)
.findFirst()
.orElse((Class) Object.class);
}
/**
* 获取一个类的第一个泛型的类型
*
* @param clazz 要获取的类
* @return 泛型
*/
public static Class getGenericType(Class clazz) {
return getGenericType(clazz, 0);
}
public static boolean instanceOf(Class clazz, Class target) {
if (clazz == null) return false;
if (clazz == target) return true;
if (target.isInterface()) {
for (Class aClass : clazz.getInterfaces()) {
if (aClass == target) return true;
}
}
if (clazz.getSuperclass() == target) return true;
else {
if (clazz.isInterface()) {
for (Class aClass : clazz.getInterfaces()) {
if (instanceOf(aClass, target)) return true;
}
}
return instanceOf(clazz.getSuperclass(), target);
}
}
/**
* 将对象转为指定的类型
*
* 支持日期，数字，boolean类型转换
*
* @param value 需要转换的值
* @param type 目标类型
* @return 转换后的值
*/
public static final T cast(Object value, Class type) {
if (value == null) return null;
Object newVal = null;
if (ClassUtils.instanceOf(value.getClass(), type)) {
newVal = value;
} else if (type == Integer.class || type == int.class) {
newVal = StringUtils.toInt(value);
} else if (type == Double.class || type == double.class || type == Float.class || type == float.class) {
newVal = StringUtils.toDouble(value);
} else if (type == Long.class || type == long.class) {
newVal = StringUtils.toLong(value);
} else if (type == Boolean.class || type == boolean.class) {
newVal = StringUtils.isTrue(value);
} else if (type == Date.class) {
newVal = DateTimeUtils.formatUnknownString2Date(value.toString());
} else if (type == String.class) {
if (value instanceof Date) {
newVal = DateTimeUtils.format(((Date) value), DateTimeUtils.YEAR_MONTH_DAY_HOUR_MINUTE_SECOND);
} else
newVal = String.valueOf(value);
}
return (T) newVal;
}
public static final Set basicClass = new HashSet<>();
static {
basicClass.add(int.class);
basicClass.add(double.class);
basicClass.add(float.class);
basicClass.add(byte.class);
basicClass.add(short.class);
basicClass.add(char.class);
basicClass.add(String.class);
}
public static boolean isBasicClass(Class clazz) {
return basicClass.contains(clazz);
}
}