📅  最后修改于: 2020-09-26 06:08:05             🧑  作者: Mango
Java 字符串 split()方法根据给定的正则表达式拆分此字符串 ,并返回一个char数组。
public String[] split(String regex, int limit) {
/* fastpath if the regex is a
(1)one-char String and this character is not one of the
RegEx's meta characters ".$|()[{^?*+\\", or
(2)two-char String and the first char is the backslash and
the second is not the ascii digit or ascii letter.
*/
char ch = 0;
if (((regex.value.length == 1 &&
".$|()[{^?*+\\".indexOf(ch = regex.charAt(0)) == -1) ||
(regex.length() == 2 &&
regex.charAt(0) == '\\' &&
(((ch = regex.charAt(1))-'0')|('9'-ch)) < 0 &&
((ch-'a')|('z'-ch)) < 0 &&
((ch-'A')|('Z'-ch)) < 0)) &&
(ch < Character.MIN_HIGH_SURROGATE ||
ch > Character.MAX_LOW_SURROGATE))
{
int off = 0;
int next = 0;
boolean limited = limit > 0;
ArrayList list = new ArrayList<>();
while ((next = indexOf(ch, off)) != -1) {
if (!limited || list.size() < limit - 1) {
list.add(substring(off, next));
off = next + 1;
} else { // last one
//assert (list.size() == limit - 1);
list.add(substring(off, value.length));
off = value.length;
break;
}
}
// If no match was found, return this
if (off == 0)
return new String[]{this};
// Add remaining segment
if (!limited || list.size() < limit)
list.add(substring(off, value.length));
// Construct result
int resultSize = list.size();
if (limit == 0)
while (resultSize > 0 && list.get(resultSize - 1).length() == 0)
resultSize--;
String[] result = new String[resultSize];
return list.subList(0, resultSize).toArray(result);
}
return Pattern.compile(regex).split(this, limit);
}
java 字符串的 split()方法有两个签名。
public String split(String regex)
and,
public String split(String regex, int limit)
regex:要应用于字符串的正则表达式。
limit:数组中字符串数的限制。如果为零,它将返回所有与正则表达式匹配的字符串。
字符串数组
PatternSyntaxException如果正则表达式的模式无效
1.4
给定的示例返回字符串的单词总数,仅不包括空格。它还包括特殊字符。
public class SplitExample{
public static void main(String args[]){
String s1="java string split method by javatpoint";
String[] words=s1.split("\\s");//splits the string based on whitespace
//using java foreach loop to print elements of string array
for(String w:words){
System.out.println(w);
}
}}
java
string
split
method
by
javatpoint
public class SplitExample2{
public static void main(String args[]){
String s1="welcome to split world";
System.out.println("returning words:");
for(String w:s1.split("\\s",0)){
System.out.println(w);
}
System.out.println("returning words:");
for(String w:s1.split("\\s",1)){
System.out.println(w);
}
System.out.println("returning words:");
for(String w:s1.split("\\s",2)){
System.out.println(w);
}
}}
returning words:
welcome
to
split
world
returning words:
welcome to split world
returning words:
welcome
to split world
在这里,我们将拆分限制作为第二个参数传递给此函数。这限制了分割字符串的数量。
public class SplitExample3 {
public static void main(String[] args) {
String str = "Javatpointtt";
System.out.println("Returning words:");
String[] arr = str.split("t", 0);
for (String w : arr) {
System.out.println(w);
}
System.out.println("Split array length: "+arr.length);
}
}
Returning words:
Java
poin
Split array length: 2