. ^ $ * + ? { } [ ] \ | ( )

String text = "Hello, my phone number is 123-456-7890";
String pattern = "\\d{3}-\\d{3}-\\d{4}"; // 匹配電話號碼格式

boolean isMatch = text.matches(pattern); // false，因為matches要求整個字符串匹配
boolean contains = Pattern.compile(pattern).matcher(text).find(); // true

// 1. 編譯正則表達式
Pattern p = Pattern.compile("a*b");

// 2. 創(chuàng)建匹配器
Matcher m = p.matcher("aaaaab");

// 3. 進行匹配
boolean b = m.matches(); // true

String email = "test@example.com";
String regex = "^[\\w-]+(\\.[\\w-]+)*@[\\w-]+(\\.[\\w-]+)+$";

boolean isValid = email.matches(regex); // true

String text = "訂單123，金額456.78元";
Pattern p = Pattern.compile("\\d+\\.?\\d*");
Matcher m = p.matcher(text);

while(m.find()) {
    System.out.println("找到數(shù)字: " + m.group());
}
// 輸出:
// 找到數(shù)字: 123
// 找到數(shù)字: 456.78

String text = "2023-05-15";
String newText = text.replaceAll("(\\d{4})-(\\d{2})-(\\d{2})", "$2/$3/$1");
// 結(jié)果: "05/15/2023"

String text = "John Doe, age 30";
Pattern p = Pattern.compile("(\\w+) (\\w+), age (\\d+)");
Matcher m = p.matcher(text);

if(m.find()) {
    System.out.println("姓名: " + m.group(1) + " " + m.group(2));
    System.out.println("年齡: " + m.group(3));
}
// 輸出:
// 姓名: John Doe
// 年齡: 30