现有年份、可选月份和可选日期的 DateTimeFormatter 验证

DateTimeFormatter Validation for Existing Year, Optional Month, and Optional Day

提问人：hooknc 提问时间：9/16/2023 最后编辑：hooknc 更新时间：9/18/2023 访问量：97

问：

我们正在尝试编写一个 DateTimeFormatter，以帮助我们验证 ISO 8601，该 ISO 8601 允许最终用户仅输入一年、一年和一个月，或一年、一个月和一天。我们还想验证输入的日期是否确实存在。

在下面的代码中，有两个日期和日期验证的示例，它们表现得很时髦。第一种是仅针对一年的验证测试，并带有可选的月份。这不能正确验证一个月的“00”。

第二个示例显示测试 （NOT） 因不正确的可选月份值而失败。

任何友好的指导将不胜感激。

import org.junit.jupiter.api.Test;

import java.time.LocalDate;
import java.time.Year;
import java.time.YearMonth;
import java.time.format.DateTimeFormatter;
import java.time.format.DateTimeFormatterBuilder;
import java.time.format.DateTimeParseException;
import java.time.format.ResolverStyle;
import java.time.temporal.TemporalQuery;

import static org.junit.jupiter.api.Assertions.assertThrows;

public class DateTimeFormatterForStackOverflowTest {

    @Test
    public void test_year_or_year_and_month_not_valid() {

        DateTimeFormatter formatter = new DateTimeFormatterBuilder()
                .appendPattern("uuuu[-MM]")
                .toFormatter()
                .withResolverStyle(ResolverStyle.STRICT);

        this.expectException("1984-0", formatter, YearMonth::from, Year::from);
        // Doesn't throw exception. 
        this.expectException("1984-00", formatter, YearMonth::from, Year::from);
        // Doesn't throw exception.
        this.expectException("1984-13", formatter, YearMonth::from, Year::from);
        // Doesn't throw exception.
        this.expectException("1984-99", formatter, YearMonth::from, Year::from);
    }

    @Test
    public void test_year_or_year_month_or_year_month_day_not_valid() {

        DateTimeFormatter formatter = new DateTimeFormatterBuilder()
                .appendPattern("[uuuu-MM-dd][uuuu-MM][uuuu]")
                .toFormatter()
                .withResolverStyle(ResolverStyle.STRICT);

        this.expectException("1984-0", formatter, LocalDate::from, YearMonth::from, Year::from);
        // Doesn't throw exception.
        this.expectException("1984-00", formatter, LocalDate::from, YearMonth::from, Year::from);
        // Doesn't throw exception.
        this.expectException("1984-13", formatter, LocalDate::from, YearMonth::from, Year::from);
        // Doesn't throw exception.
        this.expectException("1984-99", formatter, LocalDate::from, YearMonth::from, Year::from);
        this.expectException("1984-00-01", formatter, LocalDate::from, YearMonth::from, Year::from);
        this.expectException("1984-13-01", formatter, LocalDate::from, YearMonth::from, Year::from);
        this.expectException("1984-01-0", formatter, LocalDate::from, YearMonth::from, Year::from);
        this.expectException("1984-01-00", formatter, LocalDate::from, YearMonth::from, Year::from);
        this.expectException("1984-01-32", formatter, LocalDate::from, YearMonth::from, Year::from);
        this.expectException("1984-12-00", formatter, LocalDate::from, YearMonth::from, Year::from);
        this.expectException("1984-12-32", formatter, LocalDate::from, YearMonth::from, Year::from);
    }

    private void expectException(String value, DateTimeFormatter formatter, TemporalQuery<?>... queries) {

        assertThrows(DateTimeParseException.class,
                () -> formatter.parseBest(value, queries));
    }
}

测试输出：

org.opentest4j.AssertionFailedError: Expected java.time.format.DateTimeParseException to be thrown, but nothing was thrown.

    at org.junit.jupiter.api.AssertionFailureBuilder.build(AssertionFailureBuilder.java:152)
    at org.junit.jupiter.api.AssertThrows.assertThrows(AssertThrows.java:73)
    at org.junit.jupiter.api.AssertThrows.assertThrows(AssertThrows.java:35)
    at org.junit.jupiter.api.Assertions.assertThrows(Assertions.java:3083)
    at DateTimeFormatterForStackOverflowTest.expectException(DateTimeFormatterForStackOverflowTest.java:59)
    at DateTimeFormatterForStackOverflowTest.test_year_or_year_month_or_year_month_day_not_valid(DateTimeFormatterForStackOverflowTest.java:43)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.base/java.lang.reflect.Method.invoke(Method.java:566)
    at org.junit.platform.commons.util.ReflectionUtils.invokeMethod(ReflectionUtils.java:727)
    at org.junit.jupiter.engine.execution.MethodInvocation.proceed(MethodInvocation.java:60)
    at org.junit.jupiter.engine.execution.InvocationInterceptorChain$ValidatingInvocation.proceed(InvocationInterceptorChain.java:131)
    at org.junit.jupiter.engine.extension.TimeoutExtension.intercept(TimeoutExtension.java:156)
    at org.junit.jupiter.engine.extension.TimeoutExtension.interceptTestableMethod(TimeoutExtension.java:147)
    at org.junit.jupiter.engine.extension.TimeoutExtension.interceptTestMethod(TimeoutExtension.java:86)
    at org.junit.jupiter.engine.execution.InterceptingExecutableInvoker$ReflectiveInterceptorCall.lambda$ofVoidMethod$0(InterceptingExecutableInvoker.java:103)
    at org.junit.jupiter.engine.execution.InterceptingExecutableInvoker.lambda$invoke$0(InterceptingExecutableInvoker.java:93)
    at org.junit.jupiter.engine.execution.InvocationInterceptorChain$InterceptedInvocation.proceed(InvocationInterceptorChain.java:106)
    at org.junit.jupiter.engine.execution.InvocationInterceptorChain.proceed(InvocationInterceptorChain.java:64)
    at org.junit.jupiter.engine.execution.InvocationInterceptorChain.chainAndInvoke(InvocationInterceptorChain.java:45)
    at org.junit.jupiter.engine.execution.InvocationInterceptorChain.invoke(InvocationInterceptorChain.java:37)
    at org.junit.jupiter.engine.execution.InterceptingExecutableInvoker.invoke(InterceptingExecutableInvoker.java:92)
    at org.junit.jupiter.engine.execution.InterceptingExecutableInvoker.invoke(InterceptingExecutableInvoker.java:86)
    at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.lambda$invokeTestMethod$7(TestMethodTestDescriptor.java:217)
    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
    at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.invokeTestMethod(TestMethodTestDescriptor.java:213)
    at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.execute(TestMethodTestDescriptor.java:138)
    at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.execute(TestMethodTestDescriptor.java:68)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$6(NodeTestTask.java:151)
    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$8(NodeTestTask.java:141)
    at org.junit.platform.engine.support.hierarchical.Node.around(Node.java:137)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$9(NodeTestTask.java:139)
    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:138)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:95)
    at org.junit.platform.engine.support.hierarchical.ForkJoinPoolHierarchicalTestExecutorService$ExclusiveTask.compute(ForkJoinPoolHierarchicalTestExecutorService.java:185)
    at java.base/java.util.concurrent.RecursiveAction.exec(RecursiveAction.java:189)
    at java.base/java.util.concurrent.ForkJoinTask.doExec$$$capture(ForkJoinTask.java:290)
    at java.base/java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java)
    at java.base/java.util.concurrent.ForkJoinPool$WorkQueue.topLevelExec(ForkJoinPool.java:1020)
    at java.base/java.util.concurrent.ForkJoinPool.scan(ForkJoinPool.java:1656)
    at java.base/java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1594)
    at java.base/java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:183)
java java-time datetimeformatter

评论

0赞 Anonymous 9/17/2023
您能否将测试的输出粘贴到问题中？

答：

4赞 VGR 9/16/2023 #1

您可以通过打印以下结果的类型来了解正在发生的事情：parseBest

assertThrows(DateTimeParseException.class,
        () -> System.out.println(
            formatter.parseBest(value, queries).getClass()));

结果是：

java.time.Year

正如您预期的那样，“1984-00”不能解析为 YearMonth。但是您作为 TemporalQuery 传递，因此在 parseBest 发现无法使用 YearMonth.from 解析字符串后，它会再次尝试使用 Year.from，结果成功了。YearMonth::from, Year::from

为什么会成功？因为 Year 只需要 year 部分（在 DateTimeFormatter 中）即可解析。从未尝试解析月份，因此会忽略 。对于Year.from来说，该部分是否可以解析为有效月份并不重要。uuuu00

如果我想解析多个类型，并且想要确保整个字符串始终有效，我将使用一个简单的方法：

public Temporal parse(String value) {
    String len = value.length();
    if (len == 4) {
        return Year.parse(value);
    } else if (len == 7) {
        return YearMonth.parse(value);
    } else {
        return LocalDate.parse(value);
    }
}

评论

0赞 hooknc 9/16/2023
感谢您的回答/评论。我确实注意到我们在其他测试中获得了一年的时间，但您的评论解释了为什么会发生这种情况。我想我现在已经知道如何真正解决这个问题了，但这需要一些工作......首先，我认为我们必须弄清楚实际格式是否正确（使用非严格的 DateTimeFormatter），如果格式正确，则使用严格的 DateTimeFormatter 来验证日期是否确实存在。你觉得这合适吗？感谢您抽出宝贵时间接受采访。
1赞 VGR 9/16/2023
@hooknc 您必须使用单个 DateTimeFormatter 完成所有操作吗？我只想选择直接的方法：if (length == 4) temporal = Year.parse(value); else if (length == 7) temporal = YearMonth.parse(value); else temporal = LocalDate.parse(value);
0赞 hooknc 9/16/2023
否，单个 DateTimeFormatter 不是必需的。我们只是喜欢简单。但看起来我们将使用多个格式化程序来完成这项工作。非常感谢您的回答和反馈。当我们开始工作时，我会发布我们的答案。

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