Java determines whether a string is double type

java determines whether a string is a double

/**
 * 判断字符串是不是double型
 * @param str
 * @return
 */
public static boolean isNumeric(String str){ 
	 Pattern pattern = Pattern.compile("[0-9]+[.]{0,1}[0-9]*[dD]{0,1}"); 
	 Matcher isNum = pattern.matcher(str);
	 if( !isNum.matches() ){
		return false; 
	 } 
	   return true; 
}

matches() method is used to detect whether a string matches a given regular expression.

Regular expression is a powerful tool for processing strings. It is not a feature of Java. It is also available in front-end JavaScript and so on. But compared to other old high-level languages, such as C/C, this is where Java is unique than them.

Regular expression usage:

1. String matching

2. String search

3. String replacement

For more java knowledge, please pay attention to java basic tutorial.

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