處理文本對(duì)Java應(yīng)用來(lái)說(shuō)應(yīng)該算是家常便飯了，在1.4出現(xiàn)之前，Java自身提供的API非常有限，如String、StringTokenizer、StringBuffer，操作也比較單一。無(wú)非就是查找substring、分解、合并等等。到1.4的出現(xiàn)可以說(shuō)Java的文字處理上了一個(gè)臺(tái)階，因?yàn)樗С?/span>regular expression了。這可是個(gè)重量級(jí)而方便的東東啊，缺點(diǎn)是太復(fù)雜，學(xué)習(xí)起來(lái)有一定難度。相較而言，Jakarta Commons提供的StringUtils和WordUtils至今還維持著那種簡(jiǎn)潔而強(qiáng)大的美，使用起來(lái)也很順手。來(lái)看一個(gè)例子：

package sean.study.jakarta.commons.lang;

import org.apache.commons.lang.StringUtils;

public class StringUtilsAndWordUtilsUsage {

    public static void main(String[] args) {

        // data setup

        String str1 = "";

        String str2 = " ";

        String str3 = "\t";

        String str4 = null;

        String str5 = "123";

        String str6 = "ABCDEFG";

        String str7 = "It feels good to use Jakarta Commons.\r\n";

        // check for empty strings

        System.out.println("==============================");

        System.out.println("Is str1 blank? " + StringUtils.isBlank(str1));

        System.out.println("Is str2 blank? " + StringUtils.isBlank(str2));

        System.out.println("Is str3 blank? " + StringUtils.isBlank(str3));

        System.out.println("Is str4 blank? " + StringUtils.isBlank(str4));

        // check for numerics

        System.out.println("==============================");

        System.out.println("Is str5 numeric? " + StringUtils.isNumeric(str5));

        System.out.println("Is str6 numeric? " + StringUtils.isNumeric(str6));

        // reverse strings / whole words

        System.out.println("==============================");

        System.out.println("str6: " + str6);

        System.out.println("str6 reversed: " + StringUtils.reverse(str6));

        System.out.println("str7: " + str7);

        String str8 = StringUtils.chomp(str7);

        str8 = StringUtils.reverseDelimited(str8, ' ');

        System.out.println("str7 reversed whole words : \r\n" + str8);

        // build header (useful to print log messages that are easy to locate)

        System.out.println("==============================");

        System.out.println("print header:");

        String padding = StringUtils.repeat("=", 50);

        String msg = StringUtils.center(" Customised Header ", 50, "%");

        Object[] raw = new Object[]{padding, msg, padding};

        String header = StringUtils.join(raw, "\r\n");

        System.out.println(header);

    }

}

輸出的結(jié)果如下：

==============================

Is str1 blank? true

Is str2 blank? true

Is str3 blank? true

Is str4 blank? true

==============================

Is str5 numeric? true

Is str6 numeric? false

==============================

str6: ABCDEFG

str6 reversed: GFEDCBA

str7: It feels good to use Jakarta Commons.

str7 reversed whole words :

Commons. Jakarta use to good feels It

==============================

print header:

==================================================

%%%%%%%%%%%%%%% Customised Header %%%%%%%%%%%%%%%%

==================================================