[Jakarta Commons] 使用StringUtil类

最新推荐文章于 2022-04-06 09:24:25 发布

nbkangta

最新推荐文章于 2022-04-06 09:24:25 发布

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本文介绍了 Apache Commons Lang 库中的 StringUtils 类提供的多种实用字符串操作方法，包括检查空字符串、缩写字符串、查找嵌套字符串、验证字符串类型、计算字符串出现频率及比较不同字符串等。通过这些方法可以有效提高字符串处理效率。

原文地址:http://www.blogjava.net/zJun/archive/2006/07/27/60370.html

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。下面介绍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：

String htmlContent   =     "  <html>\n  "     +
                      "   <head>\n "   +
                      "     <title>Test Page</title>\n "   +
                      "   </head>\n "   +
                      "   <body>\n "   +
                      "     <p>This is a TEST!</p>\n "   +
                      "   </body>\n "   +
                      " </html> " ;

//  Extract the title from this XHTML content 
String title  =  StringUtils.substringBetween(htmlContent,  " <title> " ,  " </title> " );
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