反射工具

package com.ljyq.central.common.util;

import com.google.common.collect.Maps;
import com.ljyq.central.common.annotation.ExportFiledComment;
import org.apache.commons.lang3.StringUtils;
import org.reflections.ReflectionUtils;

import java.lang.annotation.Annotation;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.util.Date;
import java.util.LinkedHashMap;
import java.util.Objects;
import java.util.Set;


public final class ReflectionPlusUtils extends ReflectionUtils {

private final static String GETTERS_PREFIX = "get";

/**
* 反射调用对象字段的Getters方法,结果定制输出成字符串
* <p>
* 只适用于个别业务场景
*
* @param object
* @param fieldName
* @return 结果定制化
*/
public static String invokeFieldGettersMethodToCustomizeString(Object object, String fieldName) {
final Object methodResult = invokeFieldGettersMethod(object, fieldName);
if (Objects.isNull(methodResult)) {
return StringUtils.EMPTY;
}
if (methodResult.getClass().isEnum()) {
return invokeFieldGettersMethod(methodResult, "comment").toString();
} else if (methodResult instanceof Date) {
return DateUtils.formatDateByStyle((Date) methodResult);
}
return methodResult.toString();
}

/**
* 获取字段属性说明
*
* @param clazz
* @return
*/
public static LinkedHashMap<String, String> exportFiledComment(Class<?> clazz) {
Set<Field> fields = getAllFields(clazz, withAnnotation(ExportFiledComment.class));
LinkedHashMap<String, String> linkedHashMap = new LinkedHashMap<>(
Maps.newHashMapWithExpectedSize(fields.size()));
fields.forEach(field -> {
String filedComment = field.getAnnotation(ExportFiledComment.class).value();
if (StringUtils.isEmpty(filedComment)) {
filedComment = field.getName();
}
linkedHashMap.put(field.getName(), filedComment);
});
return linkedHashMap;
}

/**
* 获取字段属性说明
*
* @param clazz
* @param keyPrefix
* 字段前缀
* @param valuePrefix
* 值的前缀
* @return
*/
public static LinkedHashMap<String, String> exportFiledComment(Class<?> clazz, String keyPrefix,
String valuePrefix) {
Set<Field> fields = getAllFields(clazz, withAnnotation(ExportFiledComment.class));
LinkedHashMap<String, String> linkedHashMap = new LinkedHashMap<>(
Maps.newHashMapWithExpectedSize(fields.size()));
fields.forEach(field -> {
String filedComment = field.getAnnotation(ExportFiledComment.class).value();
if (StringUtils.isEmpty(filedComment)) {
filedComment = field.getName();
}
linkedHashMap.put(keyPrefix + field.getName(), valuePrefix + filedComment);
});
return linkedHashMap;
}

///////////////////////////////////////////////////////////////////////////
// 下面为通用方法
///////////////////////////////////////////////////////////////////////////

public static Set<Method> getMethods(Class<?> clazz, final Class<? extends Annotation> annotation) {
return getMethods(clazz, withAnnotation(annotation));
}

/**
* 反射调用对象字段的Getters方法
*
* @param object
* : 该对象
* @param fieldName
* : 该对象字段
* @return 该对象字段Getters方法结果
*/
public static Object invokeFieldGettersMethod(Object object, String fieldName) {
if (Objects.isNull(object)) {
return null;
}
final Method gettersMethod = getFieldGettersMethod(object.getClass(), fieldName);
if (Objects.isNull(gettersMethod)) {
return null;
}
try {
return gettersMethod.invoke(object);
} catch (IllegalAccessException | InvocationTargetException e) {
LogUtils.getLogger().error(e);
return null;
}
}

/**
* 反射得到对象字段Getters方法
*
* @param clazz
* : 对象
* @param fieldName
* : 对象字段
* @return <code>getFieldName</code>方法
*/
public static Method getFieldGettersMethod(Class<?> clazz, String fieldName) {
if (Objects.isNull(clazz) || StringUtils.isEmpty(fieldName)) {
return null;
}
final Set<Method> fieldNameGettersMethods = getMethods(clazz, withModifier(Modifier.PUBLIC),
withName(buildGetters(fieldName)), withParametersCount(0));
return fieldNameGettersMethods.parallelStream().findFirst().orElse(null);
}

/**
* 构建字段Getters方法名称
*
* @param fieldName
* 字段
* @return <code>getFieldName</code>
*/
private static String buildGetters(String fieldName) {
return GETTERS_PREFIX + StringPrivateUtils.firstCharToUpperCase(fieldName);
}

}