String testString = "1,2,3";
StringTokenizer st = new StringTokenizer(testString.trim(), ",");
while(st.hasMoreTokens()){
System.out.println(st.nextToken());
}
//打印出
1
2
3
StringTokenizer源代碼
/**
* Constructs a new {@code StringTokenizer} for the parameter string using
* the specified delimiters. The {@code returnDelimiters} flag is set to
* {@code false}. If {@code delimiters} is {@code null}, this constructor
* doesn't throw an {@code Exception}, but later calls to some methods might
* throw a {@code NullPointerException}.
* @param string
* the string to be tokenized
* @param delimiters
* the delimiters to use
*/
//用特定的分隔符分割輸入的字符串參數，構造一個字符串分割類。 返回分隔符標記爲假。如果分隔符參數是空，構造器不會拋出異常，但是隨後調用其他方法時可能會拋出 //空指針異常。
public StringTokenizer(String string, String delimiters){ this(string, delimiters, false); }
public StringTokenizer(String string, String delimiters, boolean returnDelimiters){
if(string == null){
throw new NullPointerException("string == null");
}
this.string = string;
this.delimiters = delimiters;
this.returnDelimiters = returnDelimiters;
this.position = 0;
}
/**
* Returns {@code true} if unprocessed tokens remain.
*
* @return {@code true} if unprocessed tokens remain.
*/
public boolean hasMoreTokens() {
if (delimiters == null) {
throw new NullPointerException("delimiters == null");
}
int length = string.length();
if (position < length) {
if (returnDelimiters)
return true; // there is at least one character and even if
// it is a delimiter it is a token
// otherwise find a character which is not a delimiter
for (int i = position; i < length; i++)
if (delimiters.indexOf(string.charAt(i), 0) == -1)
return true;
}
return false;
}
/**
* Returns the next token in the string as a {@code String}.
*
* @return next token in the string as a {@code String}.
* @throws NoSuchElementException
* if no tokens remain.
*/
public String nextToken() {
if (delimiters == null) {
throw new NullPointerException("delimiters == null");
}
int i = position;
int length = string.length();
if (i < length) {
if (returnDelimiters) {
if (delimiters.indexOf(string.charAt(position), 0) >= 0)
return String.valueOf(string.charAt(position++));
for (position++; position < length; position++)
if (delimiters.indexOf(string.charAt(position), 0) >= 0)
return string.substring(i, position);
return string.substring(i);
}
while (i < length && delimiters.indexOf(string.charAt(i), 0) >= 0)
i++;
position = i;
if (i < length) {
for (position++; position < length; position++)
if (delimiters.indexOf(string.charAt(position), 0) >= 0)
return string.substring(i, position);
return string.substring(i);
}
}
throw new NoSuchElementException();
}