Java tutorial
/* * Copyright 2002-2018 the original author or authors. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * https://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package org.springframework.format.annotation; import java.lang.annotation.Documented; import java.lang.annotation.ElementType; import java.lang.annotation.Retention; import java.lang.annotation.RetentionPolicy; import java.lang.annotation.Target; /** * Declares that a field or method parameter should be formatted as a date or time. * * <p>Supports formatting by style pattern, ISO date time pattern, or custom format pattern string. * Can be applied to {@code java.util.Date}, {@code java.util.Calendar}, {@code Long} (for * millisecond timestamps) as well as JSR-310 <code>java.time</code> and Joda-Time value types. * * <p>For style-based formatting, set the {@link #style} attribute to be the style pattern code. * The first character of the code is the date style, and the second character is the time style. * Specify a character of 'S' for short style, 'M' for medium, 'L' for long, and 'F' for full. * A date or time may be omitted by specifying the style character '-'. * * <p>For ISO-based formatting, set the {@link #iso} attribute to be the desired {@link ISO} format, * such as {@link ISO#DATE}. For custom formatting, set the {@link #pattern} attribute to be the * DateTime pattern, such as {@code yyyy/MM/dd hh:mm:ss a}. * * <p>Each attribute is mutually exclusive, so only set one attribute per annotation instance * (the one most convenient one for your formatting needs). * When the pattern attribute is specified, it takes precedence over both the style and ISO attribute. * When the {@link #iso} attribute is specified, it takes precedence over the style attribute. * When no annotation attributes are specified, the default format applied is style-based * with a style code of 'SS' (short date, short time). * * @author Keith Donald * @author Juergen Hoeller * @since 3.0 * @see java.time.format.DateTimeFormatter * @see org.joda.time.format.DateTimeFormat */ @Documented @Retention(RetentionPolicy.RUNTIME) @Target({ ElementType.METHOD, ElementType.FIELD, ElementType.PARAMETER, ElementType.ANNOTATION_TYPE }) public @interface DateTimeFormat { /** * The style pattern to use to format the field. * <p>Defaults to 'SS' for short date time. Set this attribute when you wish to format * your field in accordance with a common style other than the default style. */ String style() default "SS"; /** * The ISO pattern to use to format the field. * <p>The possible ISO patterns are defined in the {@link ISO} enum. * <p>Defaults to {@link ISO#NONE}, indicating this attribute should be ignored. * Set this attribute when you wish to format your field in accordance with an ISO format. */ ISO iso() default ISO.NONE; /** * The custom pattern to use to format the field. * <p>Defaults to empty String, indicating no custom pattern String has been specified. * Set this attribute when you wish to format your field in accordance with a custom * date time pattern not represented by a style or ISO format. * <p>Note: This pattern follows the original {@link java.text.SimpleDateFormat} style, * as also supported by Joda-Time, with strict parsing semantics towards overflows * (e.g. rejecting a Feb 29 value for a non-leap-year). As a consequence, 'yy' * characters indicate a year in the traditional style, not a "year-of-era" as in the * {@link java.time.format.DateTimeFormatter} specification (i.e. 'yy' turns into 'uu' * when going through that {@code DateTimeFormatter} with strict resolution mode). */ String pattern() default ""; /** * Common ISO date time format patterns. */ enum ISO { /** * The most common ISO Date Format {@code yyyy-MM-dd}, * e.g. "2000-10-31". */ DATE, /** * The most common ISO Time Format {@code HH:mm:ss.SSSXXX}, * e.g. "01:30:00.000-05:00". */ TIME, /** * The most common ISO DateTime Format {@code yyyy-MM-dd'T'HH:mm:ss.SSSXXX}, * e.g. "2000-10-31T01:30:00.000-05:00". * <p>This is the default if no annotation value is specified. */ DATE_TIME, /** * Indicates that no ISO-based format pattern should be applied. */ NONE } }