com.github.dennisit.vplus.data.utils.ConcurrentDateFormat Maven / Gradle / Ivy
/*
* Copyright (c) 2019-2029, Dreamlu 卢春梦 ([email protected] & www.dreamlu.net).
*
* Licensed under the GNU LESSER GENERAL PUBLIC LICENSE 3.0;
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.gnu.org/licenses/lgpl.html
*
* 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 com.github.dennisit.vplus.data.utils;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Locale;
import java.util.Queue;
import java.util.TimeZone;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentLinkedQueue;
import java.util.concurrent.ConcurrentMap;
/**
* 参考tomcat8中的并发DateFormat
*
* {@link SimpleDateFormat}的线程安全包装器。
* 不使用ThreadLocal，创建足够的SimpleDateFormat对象来满足并发性要求。
*
*
* @author L.cm
*/
public class ConcurrentDateFormat {
private final String pattern;
private final Locale locale;
private final TimeZone timezone;
private final Queue queue = new ConcurrentLinkedQueue<>();
private final static ConcurrentMap CACHE = new ConcurrentHashMap<>(3);
private ConcurrentDateFormat(String pattern, Locale locale, TimeZone timezone) {
this.pattern = pattern;
this.locale = locale;
this.timezone = timezone;
SimpleDateFormat initial = createInstance();
queue.add(initial);
}
public static ConcurrentDateFormat of(String pattern) {
// 直接使用 pattern 格式化的场景比较多，每次 new 性能太差
return CACHE.computeIfAbsent(pattern, (key) -> new ConcurrentDateFormat(key, Locale.getDefault(), TimeZone.getDefault()));
}
public static ConcurrentDateFormat of(String pattern, TimeZone timezone) {
return new ConcurrentDateFormat(pattern, Locale.getDefault(), timezone);
}
public static ConcurrentDateFormat of(String pattern, Locale locale, TimeZone timezone) {
return new ConcurrentDateFormat(pattern, locale, timezone);
}
public String format(Date date) {
SimpleDateFormat sdf = queue.poll();
if (sdf == null) {
sdf = createInstance();
}
String result = sdf.format(date);
queue.add(sdf);
return result;
}
public Date parse(String source) throws ParseException {
SimpleDateFormat sdf = queue.poll();
if (sdf == null) {
sdf = createInstance();
}
Date result = sdf.parse(source);
queue.add(sdf);
return result;
}
private SimpleDateFormat createInstance() {
SimpleDateFormat sdf = new SimpleDateFormat(pattern, locale);
sdf.setTimeZone(timezone);
return sdf;
}
}