Java字符串split()

本文概述

• Java String split()方法示例
• 带有正则表达式和长度示例的Java String split()方法
• 带有正则表达式和长度示例2的Java String split()方法

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。

内部实施

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<String> 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);
    }

签名

java字符串中的split()方法有两个签名。

public String split(String regex)
and, public String split(String regex, int limit)

参数

regex：将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。

退货

字符串数组

投掷

PatternSyntaxException如果正则表达式的模式无效

以来

1.4

Java String split()方法示例

给定的示例返回字符串中的单词总数, 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 srcmini";
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);
}
}}

立即测试

java
string
split
method
by
srcmini

带有正则表达式和长度示例的Java String split()方法

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);
}

}}

立即测试

returning words:
welcome 
to 
split 
world
returning words:
welcome to split world
returning words:
welcome 
to split world

带有正则表达式和长度示例2的Java String split()方法

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 = "srcminitt";
		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