String操作模版

需要的jar包：commons-lang3

public class StringTemple {
    private static final Log LOG = LogFactory.getLog(StringTemple.class);
    private static String STR = "this is a test string 123";

    public static void main(String[] args) {
        if (StringUtils.isNotEmpty(STR)) {
            LOG.info("STR 不为null，且长度>0");
        }
        if (StringUtils.isBlank(" ")) {
            LOG.info("如果空格为空的话使用isBlank判断");
        }
        String trimToNull = StringUtils.trimToNull("  ");
        LOG.info(trimToNull);
        String trimToEmpty = StringUtils.trimToEmpty("  ");
        LOG.info(trimToEmpty);

        //如果字符串为 ""," ",null,则给一个默认的字符串“blank”
        String blank = StringUtils.defaultIfBlank(" ", "blank");
        LOG.info(blank);
        //如果字符串为"",null，则给一个默认的字符串“empty”
        String empty = StringUtils.defaultIfEmpty("", "empty");
        LOG.info(empty);

        //把数组的每个值用特定的符号连起来
        String[] str = {"a", "b", "c"};
        String join = StringUtils.join(str, ",");
        LOG.info(join);

        //字符串首字母大写
        String capitalize = StringUtils.capitalize(STR);
        LOG.info(STR + "首字母大写 ： " + capitalize);
        //字符串首字母小写
        String uncapitalize = StringUtils.uncapitalize(capitalize);
        LOG.info(capitalize + "首字母小写 ： " + uncapitalize);
        boolean isContainIgnoreCase = StringUtils.containsIgnoreCase(STR, "Is");
        LOG.info(isContainIgnoreCase);

        //字符串替换
        String replace = StringUtils.replace(STR, "is", "si");
        LOG.info(STR + "把is 替换成 si ： " + replace);

        //判断字符串是否是纯数字
        String numStr = "123";
        boolean isNumeric = StringUtils.isNumeric(numStr);
        LOG.info(numStr + " is numeric ? : " + isNumeric);
        //判断字符串是为是字母或数字
        String alphanStr = "abc123";
        boolean isAlphanumeric = StringUtils.isAlphanumeric(alphanStr);
        LOG.info(alphanStr + " is alphanumeric ？ ： " + isAlphanumeric);

        String defaultString = StringUtils.defaultString(numStr);
        LOG.info(defaultString);

        //字符串重复n次
        String repeat = StringUtils.repeat(STR, " ", 3);
        LOG.info(STR + "重复3次后结果为：" + repeat);
        String reverse = StringUtils.reverse(STR);
        LOG.info(STR + "反转之后的结果是： " + reverse);

        //长度不够时，向左用*补位
        String leftPad = StringUtils.leftPad("this is", 10, "*");
        LOG.info(leftPad);
        //长度不够时，向右用*补位
        String rightPad = StringUtils.rightPad("this is", 10, "*");
        LOG.info(rightPad);

        //判断字符串是否包含空格
        boolean containWhitespace = StringUtils.containsWhitespace(STR);
        LOG.info(STR + "包含空格？ " + containWhitespace);
        //删除所有的空格
        String delWithspace = StringUtils.deleteWhitespace("this is ");
        LOG.info(STR + "去掉空格之后结果为 ： " + delWithspace);

        String subAfter = StringUtils.substringAfter(STR, "st");
        LOG.info(STR + "after "st" substringAfter is : " + subAfter);
        String subBefore = StringUtils.substringBefore(STR, "is");
        LOG.info(STR + "after "is" substringBefore is : " + subBefore);
        String subBetween = StringUtils.substringBetween(STR, "is", "st");
        LOG.info(STR + "after substringBetween "is" and "st" is : " + subBetween);

    }
}