Groovy 4.x遍历LocalDate范围报错，原Groovy3.x代码失效求修复方案

问题场景 #

以下代码在Groovy 3.x中可正常执行，但在Groovy 4.x中抛出异常：

LocalDate startDate = LocalDate.of(2023, Month.JULY, 1)
LocalDate endDate = LocalDate.of(2023, Month.JULY, 31)
LocalDate[] businessDates = (startDate..endDate).collect()
businessDates.stream().forEach { print it }

抛出的异常信息：

Caught: groovy.lang.MissingMethodException: 
No signature of method: java.time.LocalDate.next() is applicable for argument types: () values: []
Possible solutions: get(java.time.temporal.TemporalField), wait(), now(), wait(long), now(java.time.Clock), now(java.time.ZoneId)
groovy.lang.MissingMethodException: 
No signature of method: java.time.LocalDate.next() is applicable for argument types: () values: []
Possible solutions: get(java.time.temporal.TemporalField), wait(), now(), wait(long), now(java.time.Clock), now(java.time.ZoneId)
    at Main.run(Main.groovy:4)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77)
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)

原因分析 #

Groovy 3.x会为实现Comparable接口的类自动生成next()/previous()方法，以此支持..范围操作符的遍历逻辑。但Groovy 4.x移除了这一自动生成逻辑，导致LocalDate无法再通过startDate..endDate生成日期序列，触发next()方法不存在的异常。

修复方案 #

方案1：使用Java原生datesUntil方法（推荐） #

利用Java 8+为LocalDate提供的datesUntil方法生成日期流，注意该方法默认不包含结束日期，需传入endDate.plusDays(1)来包含最后一天：

LocalDate startDate = LocalDate.of(2023, Month.JULY, 1)
LocalDate endDate = LocalDate.of(2023, Month.JULY, 31)
LocalDate[] businessDates = startDate.datesUntil(endDate.plusDays(1)).toArray(LocalDate[]::new)
businessDates.stream().forEach { print it }

方案2：手动循环遍历日期 #

通过手动循环递增日期，收集成列表后再转为数组：

LocalDate startDate = LocalDate.of(2023, Month.JULY, 1)
LocalDate endDate = LocalDate.of(2023, Month.JULY, 31)
List<LocalDate> dateList = []
LocalDate currentDate = startDate
while (!currentDate.isAfter(endDate)) {
    dateList.add(currentDate)
    currentDate = currentDate.plusDays(1)
}
LocalDate[] businessDates = dateList.toArray(new LocalDate[0])
businessDates.stream().forEach { print it }

方案3：添加Groovy扩展方法（全局复用） #

如果需要在多处复用..范围遍历逻辑，可以为LocalDate手动添加next()扩展方法，让原代码保持不变：

// 定义LocalDate的扩展方法
extension module java.time.LocalDate {
    LocalDate next() {
        return plusDays(1)
    }
}

// 原代码可直接正常运行
LocalDate startDate = LocalDate.of(2023, Month.JULY, 1)
LocalDate endDate = LocalDate.of(2023, Month.JULY, 31)
LocalDate[] businessDates = (startDate..endDate).collect()
businessDates.stream().forEach { print it }

内容的提问来源于stack exchange，提问作者developer