常用的String操作--持续更新

String拼接

// 方式1：apache common long3
String fileName = StringUtils.join(new String[]{"生产员工绩效",
        LocalDateTime.now().format(DateTimeFormatter.ofPattern("YYYYMMddHHmmss")),
        randomAlphanumeric(4).toLowerCase()}, "_");
// aa,bb,cc
String join = StringUtils.join(new String[]{"aa","bb","cc"}, ",");

// 方式2: guava
Joiner.on("_").join(new String[]{"aa","bb"});  // aa_bb

// 方式1: jdk，改方法底层是StringJoiner
String.join("|", "aa", "bb"); // aa|bb
// aa,bb
StringJoiner sj = new StringJoiner(",")
                .add("aa")
                .add("bb");

对于异常的处理：

// ,bb,cc
String join = StringUtils.join(new String[]{null,"bb","cc"}, ",");
// null|bb|cc
String join1 = String.join("|", new String[]{null, "bb", "cc"});
// 抛异常 java.lang.NullPointerException
String join2 = Joiner.on("_").join(new String[]{null, "bb", "cc"});