Java String 过滤子字符串

心已赠人 2022-06-12 10:50 190阅读 0赞

## Java String 过滤子字符串 ##

前几天写到获取Editor值的时候，获取的值(String)中竟然还包含一堆Html的标记．而我不需要或者根本不想要这些标签的存在．

遂寻找解决办法，研究过滤标记的方法：

#### 目的：    ####

把html的一些标记符（如<b></b>、<p></p>、<span></span>、<div></div>等）去掉。

#### 解决方法有三，    ####

第一种是在Editor编辑组件中添加escape="false"来屏蔽html标记，从组件角度着手．但是并不能起作用．画个问号？

第二种是用String类提供的方法，将html标记替换掉，从字符串角度．

第三种是用正则表达式去除带有html标记的富文本，从文本角度，我没有采取这种方法，可能这种方法效率较第二种高．

两种方法因为需要考虑的html标记元素还是比较多的，所以会导致效率降低。

我们来着重看一下第二种方法：

## String 类提供的替换方法： ##

> **问题转换成：**
> 
> > 过滤掉String(java)中指定的子字符串．
> > 
> >   
> > 
> 
> 我们来看一下[\[官方文档\]][Link 1]中有关字符串内容转换的方法：
> 
> >   
> >

<table> 
 <tbody> 
  <tr> 
   <td align="left"><code>String&nbsp;&nbsp;&nbsp; <br> </code></td> 
   <td><code><strong>replace</strong>(char&nbsp;oldChar, char&nbsp;newChar)</code> 
    <div>
      Returns a new string resulting from replacing all occurrences of 
     <code>oldChar</code> in this string with 
     <code>newChar</code>. 
    </div> </td> 
  </tr> 
  <tr> 
   <td><code>String</code></td> 
   <td><code><strong>replace</strong>(CharSequence&nbsp;target,CharSequence&nbsp;replacement)</code> 
    <div>
      Replaces each substring of this string that matches the literal target sequence with the specified literal replacement sequence. 
    </div> </td> 
  </tr> 
  <tr> 
   <td><code>String</code></td> 
   <td><code><strong>replaceAll</strong>(String&nbsp;regex,String&nbsp;replacement)</code> 
    <div>
      Replaces each substring of this string that matches the given regular expression with the given replacement. 
    </div> </td> 
  </tr> 
  <tr> 
   <td><code>String&nbsp;&nbsp;&nbsp;&nbsp; <br> </code></td> 
   <td><code><strong>replaceFirst</strong>(String&nbsp;regex,String&nbsp;replacement)</code> 
    <div>
      Replaces the first substring of this string that matches the givenregular expression with the given replacement. 
    </div> </td> 
  </tr> 
 </tbody> 
</table>

<table> 
 <tbody> 
  <tr> 
   <td align="left"><code>String&nbsp; <br> </code></td> 
   <td><code><strong>toLowerCase</strong>()</code> 
    <div>
      Converts all of the characters in this 
     <code>String</code> to lower case using the rules of the default locale. 
    </div> </td> 
  </tr> 
  <tr> 
   <td><code>String</code></td> 
   <td><code><strong>toLowerCase</strong>(Locale&nbsp;locale)</code> 
    <div>
      Converts all of the characters in this 
     <code>String</code> to lower case using the rules of the given 
     <code>Locale</code>. 
    </div> </td> 
  </tr> 
  <tr> 
   <td><code>String</code></td> 
   <td><code><strong>toString</strong>()</code> 
    <div>
      This object (which is already a string!) is itself returned. 
    </div> </td> 
  </tr> 
  <tr> 
   <td><code>String</code></td> 
   <td><code><strong>toUpperCase</strong>()</code> 
    <div>
      Converts all of the characters in this 
     <code>String</code> to upper case using the rules of the default locale. 
    </div> </td> 
  </tr> 
  <tr> 
   <td><code>String</code></td> 
   <td><code><strong>toUpperCase</strong>(Locale&nbsp;locale)</code> 
    <div>
      Converts all of the characters in this 
     <code>String</code> to upper case using the rules of the given 
     <code>Locale</code>. 
    </div> </td> 
  </tr> 
  <tr> 
   <td><code>String</code></td> 
   <td><code><strong>trim</strong>()</code> 
    <div>
      Returns a copy of the string, with leading and trailing whitespace omitted. 
    </div> </td> 
  </tr> 
 </tbody> 
</table>

> 正好有我们可以用的方法，将标签一个一个的去掉：  
> 
> 
> > String.replaceAll(String s1,String s2);  
> > 
> 
> 例如：
> 
> > code.replaceAll("<br>","").replaceAll("&nbsp;","");  
> >

过滤前：

>     20:44:20,593 INFO  [cn.edu.sdut.softlab.service.AbstractFacade] (default task-23)
>     
>     public class Student { <br>   public static void main(String[] args) { <br>    System.out.println("hello world"); <br> } }
> 
>   
>   
>

过滤后

>     20:44:21,595 INFO  [cn.edu.sdut.softlab.service.AbstractFacade] (default task-23)
>     
>     public class Student { public static void main(String[] args) { System.out.println("hello world"); } }
> 
>   
>   
>

参考资料:

> http://docs.[Oracle][].com/javase/7/docs/api/java/lang/String.html  
> 
> 
> http://www.cnblogs.com/technology/archive/2012/09/26/2703445.html  
> 
> 
> https://stackoverflow.com/questions/11520885/primeface-editor-value-display-without-tags  
>

[Link 1]: http://docs.oracle.com/javase/7/docs/api/java/lang/String.html
[Oracle]: http://lib.csdn.net/base/oracle