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feilong is a suite of core and expanded libraries that include utility classes, http, excel,cvs, io classes, and much much more.
/*
* Copyright (C) 2008 feilong
*
* 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
*
* http://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 com.feilong.core.util;
import static com.feilong.core.util.MapUtil.newLinkedHashMap;
import static java.util.Collections.emptyMap;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import com.feilong.core.Validate;
/**
* 正则表达式工具类.
*
* @author feilong
* @see "RegexPattern"
* @see java.util.regex.Pattern
* @see java.util.regex.Matcher
* @see java.lang.String#matches(String)
* @since 1.0.0
* @since jdk1.4
*/
public final class RegexUtil{
/** The Constant LOGGER. */
private static final Logger LOGGER = LoggerFactory.getLogger(RegexUtil.class);
/**
* Pattern cache提高速度.
*
* @see RegexUtil 加上缓存
* @since 1.10.6
*/
private static final Map PATTERN_CACHE = new ConcurrentHashMap<>();
//---------------------------------------------------------------
/** Don't let anyone instantiate this class. */
private RegexUtil(){
//AssertionError不是必须的. 但它可以避免不小心在类的内部调用构造器. 保证该类在任何情况下都不会被实例化.
//see 《Effective Java》 2nd
throw new AssertionError("No " + getClass().getName() + " instances for you!");
}
//---------------------------------------------------------------
/**
* 编译给定正则表达式 regexPattern ,并尝试将给定输入 input 与其匹配.
*
*
* {@link Pattern#matches(String, CharSequence)} 等价于{@link #getMatcher(String, CharSequence)}.matches();
*
*
* @param regexPattern
* 正则表达式字符串,pls use RegexPattern
* @param input
* The character sequence to be matched,support {@link String},{@link StringBuffer},{@link StringBuilder}... and so on
* @return 如果 regexPattern 是null,抛出 {@link NullPointerException}
* 如果 input 是null,返回 false
* 如果input 符合 regex的正则表达式格式,返回true,否则返回 false;
* @see #getMatcher(String, CharSequence)
* @see Matcher#matches()
* @see Pattern#matches(String, CharSequence)
* @since 1.0.7
* @since 1.13.2 change, if input is null, return false from NPE
*/
public static boolean matches(final String regexPattern,final CharSequence input){
Validate.notNull(regexPattern, "regexPattern can't be null!");
if (null == input){
return false;
}
return getMatcher(regexPattern, input).matches();
}
//---------------------------------------------------------------
/**
* 返回在以前匹配操作期间由给定组捕获的输入子序列.
*
*
* 对于匹配器 m、输入序列 s 和组索引 g,表达式 m.group(g) 和 s.substring(m.start(g), m.end(g))是等效的.
* 捕获组是从 1开始从左到右的索引.组0表示整个模式,因此表达式 m.group(0)等效于 m.group().
*
*
* 示例:
*
*
*
*
* String regexPattern = "(.*?)@(.*?)";
* String email = "[email protected]";
*
* RegexUtil.group(regexPattern, email);
*
*
* 返回:
*
*
* 0 [email protected]
* 1 feilong
* 2 163.com
*
*
*
*
* @param regexPattern
* 正则表达式模式,比如 (.*?)@(.*?)
* @param input
* 需要被group的字符串,比如 [email protected],support {@link String},{@link StringBuffer},{@link StringBuilder}... and so on
* @return 如果 regexPattern 是null,抛出 {@link NullPointerException}
* 如果 input 是null,抛出 {@link NullPointerException}
* 如果 匹配不了,返回 {@link java.util.Collections#emptyMap()}
* @see #getMatcher(String, CharSequence)
* @see Matcher#group(int)
* @since 1.0.7
*/
public static Map group(final String regexPattern,final CharSequence input){
Matcher matcher = getMatcher(regexPattern, input);
if (!matcher.matches()){
LOGGER.trace("[not matches] ,\n\tregexPattern:[{}] \n\tinput:[{}]", regexPattern, input);
return emptyMap();
}
//---------------------------------------------------------------
int groupCount = matcher.groupCount();
Map map = newLinkedHashMap(groupCount + 1);
for (int i = 0; i <= groupCount; ++i){
//匹配的索引
String groupValue = matcher.group(i); //map.put(0, matcher.group());// 捕获组是从 1 开始从左到右的索引.组0表示整个模式,因此表达式 m.group(0) 等效于 m.group().
LOGGER.trace("matcher group[{}],start-end:[{}-{}],groupValue:[{}]", i, matcher.start(i), matcher.end(i), groupValue);
map.put(i, groupValue);//groupValue
}
//---------------------------------------------------------------
if (LOGGER.isTraceEnabled()){
LOGGER.trace("regexPattern:[{}],input:[{}],groupMap:{}", regexPattern, input, map);
}
return map;
}
/**
* 返回在以前匹配操作期间由给定组捕获的输入子序列.
*
*
* 对于匹配器 m、输入序列 s 和组索引 g,表达式 m.group(g) 和 s.substring(m.start(g), m.end(g))是等效的.
* 捕获组是从 1开始从左到右的索引.组0表示整个模式,因此表达式 m.group(0)等效于 m.group().
*
*
* 示例:
*
*
*
*
*
* String regexPattern = "(.*?)@(.*?)";
* String email = "[email protected]";
*
* RegexUtil.group(regexPattern, email, 1);//feilong
* RegexUtil.group(regexPattern, email, 2);//163.com
*
*
*
*
*
* @param regexPattern
* 正则表达式模式,比如 (.*?)@(.*?)
* @param input
* 需要被group的字符串,比如 [email protected],support {@link String},{@link StringBuffer},{@link StringBuilder}... and so on
* @param groupNo
* 组号,从0开始
* @return 如果 regexPattern 是null,抛出 {@link NullPointerException}
* 如果 input 是null,抛出 {@link NullPointerException}
* 如果 {@code input < 0} ,抛出 {@link IllegalArgumentException}
* @see #getMatcher(String, CharSequence)
* @see Matcher#group(int)
* @since 1.0.7
*/
public static String group(final String regexPattern,final CharSequence input,final int groupNo){
Validate.isTrue(groupNo >= 0, "groupNo must >=0");
Map map = group(regexPattern, input);
return map.get(groupNo);
}
//---------------------------------------------------------------
/**
* Gets the matcher.
*
* @param regexPattern
* 正则表达式字符串,pls use {@link "RegexPattern"}
* @param input
* The character sequence to be matched,support {@link String},{@link StringBuffer},{@link StringBuilder}... and so on
* @return 如果 regexPattern 是null,抛出 {@link NullPointerException}
* 如果 input 是null,抛出 {@link NullPointerException}
* @see Pattern#compile(String)
* @since 1.0.7
*/
private static Matcher getMatcher(final String regexPattern,final CharSequence input){
return getMatcher(regexPattern, input, 0);
}
/**
* Gets the matcher.
*
* @param regexPattern
* 正则表达式字符串,pls use {@link "RegexPattern"}
* @param input
* The character sequence to be matched,support {@link String},{@link StringBuffer},{@link StringBuilder}... and so on
* @param flags
* 如果需要多个组合,可以使用罗辑或
* Pattern.compile(regex, CASE_INSENSITIVE | DOTALL);
*
* - {@link Pattern#CASE_INSENSITIVE} 匹配字符时与大小写无关,该标志默认只考虑US ASCII字符.
* - {@link Pattern#MULTILINE} ^和$匹配一行的开始和结尾,而不是整个输入
* - {@link Pattern#UNICODE_CASE} 当与CASE_INSENSITIVE结合时,使用Unicode字母匹配
* - {@link Pattern#CANON_EQ} 考虑Unicode字符的规范等价
* - {@link Pattern#DOTALL} 当使用此标志时,.符号匹配包括行终止符在内的所有字符
* - {@link Pattern#UNIX_LINES} 当在多行模式下匹配^和$时,只将'\n'看作行终止符
* - {@link Pattern#LITERAL} 启用模式的字面值解析.
* - {@link Pattern#COMMENTS} 模式中允许空白和注释.
* 此模式将忽略空白和在结束行之前以 # 开头的嵌入式注释.
* 通过嵌入式标志表达式 (?x) 也可以启用注释模式.
*
*
* @return 如果 regexPattern 是null,抛出 {@link NullPointerException}
* 如果 input 是null,抛出 {@link NullPointerException}
* @see Pattern#compile(String, int)
* @since 1.5.3
*/
private static Matcher getMatcher(final String regexPattern,final CharSequence input,final int flags){
Validate.notNull(regexPattern, "regexPattern can't be null!");
Validate.notNull(input, "input can't be null!");
Pattern pattern = buildPattern(regexPattern, flags);
return pattern.matcher(input);
}
//---------------------------------------------------------------
/**
* 如果cache中有,那么直接返回, 如果没有构造一个并塞到cache中.
*
* @param regexPattern
* the regex pattern
* @param flags
* the flags
* @return the pattern
* @since 1.10.6
*/
public static Pattern buildPattern(final String regexPattern,final int flags){
String key = regexPattern + "@" + flags;
return PATTERN_CACHE.computeIfAbsent(key, k -> Pattern.compile(regexPattern, flags));
}
}