Java String split()方法详细教程

public String[] split(String regex, int limit) {  
        /* 如果正则表达式是一个快速路径 
         (1)one-char String 且此字符不是其中之一 
            正则表达式的元字符“.$|()[{^?*+\\”，或 
         (2)双字符字符串，第一个字符是反斜杠和 
            第二个不是 ascii 数字或 ascii 字母
         */  
        char ch = 0;  
        if (((regex.value.length == 1 &&  
             ".$|()[{^?*+\\".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 {    // 最后一个
                    //assert (list.size() == limit - 1);  
                    list.add(substring(off, value.length));  
                    off = value.length;  
                    break;  
                }  
            }  
            // 如果未找到匹配项，则返回此
            if (off == 0)  
                return new String[]{this};  
  
            //添加剩余部分  
            if (!limited || list.size() < limit)  
                list.add(substring(off, value.length));  
  
            //构建结果 
            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);  
    }

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

public class SplitExample{  
public static void main(String args[]){  
String s1="java string split method by javatpoint";  
String[] words=s1.split("\\s");//根据空格分割字符串
//使用 java foreach 循环打印字符串数组的元素
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

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