fix jdk8

hutool-core/src/main/java/cn/hutool/core/convert/ConverterRegistry.java

@@ -136,7 +136,7 @@ public class ConverterRegistry implements Serializable{
 	 * @return 转换器
 	 */
 	public <T> Converter<T> getConverter(Type type, boolean isCustomFirst) {
-		Converter<T> converter = null;
+		Converter<T> converter;
 		if (isCustomFirst) {
 			converter = this.getCustomConverter(type);
 			if (null == converter) {

hutool-core/src/main/java/cn/hutool/core/convert/impl/Jdk8DateConverter.java

@@ -1,11 +1,14 @@
 package cn.hutool.core.convert.impl;
 
-import java.lang.reflect.Method;
-
 import cn.hutool.core.convert.AbstractConverter;
-import cn.hutool.core.util.ClassUtil;
 import cn.hutool.core.util.ReflectUtil;
 
+import java.lang.reflect.Method;
+import java.time.Instant;
+import java.time.LocalDate;
+import java.time.LocalDateTime;
+import java.time.format.DateTimeFormatter;
+
 /**
  * JDK8中新加入的java.time包对象解析转换器<br>
  * 通过反射调用“parse方法”，支持的对象包括：
@@ -99,9 +102,12 @@ public class Jdk8DateConverter extends AbstractConverter<Object> {
 	private Object parseFromCharSequence(CharSequence value) {
 		Method method;
 		if (null != this.format) {
-			final Object dateTimeFormatter = getDateTimeFormatter();
-			method = ReflectUtil.getMethod(this.targetType, "parse", CharSequence.class, dateTimeFormatter.getClass());
-			return ReflectUtil.invokeStatic(method, value, dateTimeFormatter);
+			final DateTimeFormatter formatter = DateTimeFormatter.ofPattern(this.format);
+			method = ReflectUtil.getMethod(this.targetType, "parse", CharSequence.class, DateTimeFormatter.class);
+			if(Instant.class.isAssignableFrom(this.targetType)){
+				return formatter.parse(value, Instant::from);
+			}
+			return ReflectUtil.invokeStatic(method, value, formatter);
 		} else {
 			method = ReflectUtil.getMethod(this.targetType, "parse", CharSequence.class);
 			return ReflectUtil.invokeStatic(method, value);
@@ -110,43 +116,15 @@ public class Jdk8DateConverter extends AbstractConverter<Object> {
 
 	/**
 	 * 通过反射将Long型时间戳转换为java.time中的对象
-	 * 
+	 *
 	 * @param time 时间戳
 	 * @return java.time中的对象
 	 */
 	private Object parseFromLong(Long time) {
 		String targetName = this.targetType.getName();
 		if ("java.time.Instant".equals(targetName)) {
-			return toInstant(time);
-		}
-		return null;
-	}
-
-	/**
-	 * 反射获取java.time.format.DateTimeFormatter对象
-	 * 
-	 * @return java.time.format.DateTimeFormatter对象
-	 */
-	private Object getDateTimeFormatter() {
-		if (null != this.format) {
-			return ClassUtil.invoke("java.time.format.DateTimeFormatter.ofPattern", false, this.format);
+			return Instant.ofEpochMilli(time);
 		}
 		return null;
 	}
-
-	/**
-	 * Long转 java.time.Instant
-	 * 
-	 * @param time 时间戳
-	 * @return java.time.Instant
-	 */
-	private Object toInstant(Long time) {
-		return ClassUtil.invoke("java.time.Instant.ofEpochMilli", false, time);
-	}
-
-	@SuppressWarnings("unchecked")
-	@Override
-	public Class<Object> getTargetType() {
-		return (Class<Object>) this.targetType;
-	}
 }