Java 正则表达式详细使用

Java 正则表达式

java.util.regex.Pattern
java.util.regex.Matcher

1.Match
match 是从字符串最头部开始匹配，一直到结束，需要匹配整个串

String content = "Welcome, bob!";
content.match("bob");    //false
content.match(".*bob")   //false
content.match(".*bob.*") //true

String str="test@yahoo.com.cn";
Pattern pattern = Pattern.compile("[\w\.\-]+@([\w\-]+\.)+[\w\-]+",Pattern.CASE_INSENSITIVE);
Matcher matcher = pattern.matcher(str);
boolean a = matcher.matches(); //匹配的时候返回true

2.Find

boolean b = matcher.find(); //包含正则匹配的串为true
// 找到所有匹配的串
while(matcher.find()) {
    String extracted = matcher.group(0)
}

3.Replace

matcher.replaceFirst("")
matcher.replaceAll("");

4.Group

group(0) 代表整个表达式
String line = "#星座运势#20171013";
String pattern = "\#(\p{L}*)\#(\d+)";  //p{L}  匹配 unicode any kind of letter from any language
// 创建 Pattern 对象
Pattern r = Pattern.compile(pattern);
 
// 现在创建 matcher 对象
Matcher m = r.matcher(line);

if (m.find( )) {
   System.out.println("Found value: " + m.group(0) );    // "#星座运势#20171013"
   System.out.println("Found value: " + m.group(1) );    // 星座运势
   System.out.println("Found value: " + m.group(2) );    // 20171013
} else {
   System.out.println("NO MATCH");
}