反射工具

Posted 2022-10-16 dayuss

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);