org.apache.commons.lang.StringUtils

org.apache.commons.lang.StringUtils中提供许多有用的字符串操作方法，了解这些方法，我们可以避免许多不必要的重复工作。其中比较有用的几个方法：

检查空字符串：

StringUtils.isBlank(String str);
StringUtils.isNotBlank(String str);

缩写字符串：

String test  =   " This is a test of the abbreviation. "
System.out.println( StringUtils.abbreviate( test,  10  ) );

[Console输出]
This is

查找嵌套字符串：

java 代码

String htmlContent  =   " \n "   +
                      "   \n "   +
                      "     \n "   +
                      "   \n "   +
                      "   \n "   +
                      "     
    This is a TEST!
    \n "   +
                      "   \n "   +
                      "  " ;

//  Extract the title from this XHTML content
String title  =  StringUtils.substringBetween(htmlContent,  "  " );
System.out.println(  " Title:  "   +  title );

[Console输出]
Title: Test Page

验证字符串：

String test1  =   " ORANGE " ;

String test2  =   " ICE9 " ;

String test3  =   " ICE CREAM " ;

String test4  =   " 820B Judson Avenue " ;


boolean  t1val  =  StringUtils.isAlpha( test1 );  //  returns true

boolean  t2val  =  StringUtils.isAlphanumeric( test2 );  //  returns true

boolean  t3val  =  StringUtils.isAlphaSpace( test3 );  //  returns true

boolean  t4val  =  

    StringUtils.isAlphanumericSpace( test4 );  //  returns true

计算字符串出现频率：

File manuscriptFile  =   new  File( " manuscript.txt " );

Reader reader  =   new  FileReader( manuscriptFile );

StringWriter stringWriter  =   new  StringWriter( );

while ( reader.ready( ) )  { writer.write( reader.read( ) ); }

String manuscript  =  stringWriter.toString( );

//  Convert string to lowercase

manuscript  =  StringUtils.lowerCase(manuscript);

//  count the occurrences of "futility"

int  numFutility  =  StringUtils.countMatches( manuscript,  " futility "  );

比较不同字符串：

int  dist  =  StringUtils.getLevenshteinDistance(  " Word " ,  " World "  );

String diff  =  StringUtils.difference(  " Word " ,  " World "  );

int  index  =  StringUtils.indexOfDifference(  " Word " ,  " World "  );

System.out.println(  " Edit Distance:  "   +  dist );

System.out.println(  " Difference:  "   +  diff );

System.out.println(  " Diff Index:  "   +  index );

[Console输出]
Edit Distance:  2

Difference: ld

Diff Index:  3