字符串替換（不區分大小寫）

String str = "alpha beta, Alpha beta, alPHa beta, ALPHA beta";
System.out.println("Ignore case when replacing.\n" + "Replace any
    version of 'alpha' " + "with 'zeta' in:\n" + "   " + str);

// 下面的代碼用於替換str字符串中所有alpha字符串，不區分大小寫的替換

String result = str.replaceAll("(?i)alpha", "zeta");

System.out.println("After replacement:\n" + "   " + result);