Java 计算正则表达式出现在较大的String中的次数。
计算正则表达式出现在较大的String中的次数。
实例源码：
源代码：
执行
执行中...
x
1
2
/*3
4
* Copyright 2013 Guidewire Software, Inc.5
6
*/7
8
/**9
10
* This class is based, in part, on org.apache.commons.lang.StringUtils and is intended11
12
* to break the dependency on that project.13
14
*15
16
* @author <a href="http://jakarta.apache.org/turbine/">Apache Jakarta Turbine</a>17
18
* @author <a href="mailto:jon@latchkey.com">Jon S. Stevens</a>19
20
* @author Daniel L. Rall21
22
* @author <a href="mailto:gcoladonato@yahoo.com">Greg Coladonato</a>23
24
* @author <a href="mailto:ed@apache.org">Ed Korthof</a>25
26
* @author <a href="mailto:rand_mcneely@yahoo.com">Rand McNeely</a>27
28
* @author Stephen Colebourne29
30
* @author <a href="mailto:fredrik@westermarck.com">Fredrik Westermarck</a>31
32
* @author Holger Krauth33
34
* @author <a href="mailto:alex@purpletech.com">Alexander Day Chaffee</a>35
36
* @author <a href="mailto:hps@intermeta.de">Henning P. Schmiedehausen</a>37
38
* @author Arun Mammen Thomas39
40
* @author Gary Gregory41
42
* @author Phil Steitz43
44
* @author Al Chou45
46
* @author Michael Davey47
48
* @author Reuben Sivan49
50
* @author Chris Hyzer51
52
* Johnson53
54
55
*/56
/*57
来 自*58
n o w j a v a . c o m - 时代Java59
*/60
61
//package com.nowjava;62
63
64
import java.util.regex.Pattern;65
66
import java.util.regex.Matcher;67
68
69
public class Main {70
71
public static void main(String[] argv) {72
73
String str = "nowjava.com";74
75
String regexp = "nowjava.com";76
77
System.out.println(countRegexpMatches(str, regexp));78
79
}80
81
82
/**83
84
* <p>Counts how many times the regexp appears in the larger String.</p>85
86
*87
88
* <p>A <code>null</code> or empty ("") String input returns <code>0</code>.</p>89
90
*91
92
* <pre>93
94
* countMatches(null, *) = 095
96
* countMatches("", *) = 097
98
* countMatches("abba", null) = 099
100
* countMatches("abba", "") = 0101
102
* countMatches("abba", "a") = 2103
104
* countMatches("abba", "ab") = 1105
106
* countMatches("abba", ".b") = 2107
108
* countMatches("abba", "xxx") = 0109
110
* </pre>111
112
*113
114
* @param str the String to check, may be null115
116
* @param regexp the regexp to count, may be null117
118
* @return the number of occurrences, 0 if either String is <code>null</code>119
120
*/121
122
public static int countRegexpMatches(String str, String regexp) {123
124
if (isEmpty(str) || isEmpty(regexp)) {125
126
return 0;127
128
}//from 时 代 J a v a 公 众 号 - nowjava.com129
130
Pattern pattern = Pattern.compile(regexp);131
132
Matcher matcher = pattern.matcher(str);133
134
int i = 0;135
136
while (matcher.find()) {137
138
i++;139
140
}141
142
return i;143
144
}145
146
147
/**148
149
* <p>Checks if a String is empty ("") or null.</p>150
151
*152
153
* <pre>154
155
* StringUtils.isEmpty(null) = true156
157
* StringUtils.isEmpty("") = true158
159
* StringUtils.isEmpty(" ") = false160
161
* StringUtils.isEmpty("bob") = false162
163
* StringUtils.isEmpty(" bob ") = false164
165
* </pre>166
167
*168
169
* <p>NOTE: This method changed in Lang version 2.0.170
171
* It no longer trims the String.172
173
* That functionality is available in isBlank().</p>174
175
*176
177
* @param str the String to check, may be null178
/**代码未完, 请加载全部代码(NowJava.com).**/执行结果：
本文系作者在时代Java发表，未经许可，不得转载。如有侵权，请联系nowjava@qq.com删除。
编辑于
关注时代Java