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ronalke
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Java 判断字符串是否为空

 
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以下是 Java 判断字符串是否为空的三种方法.
方法一: 最多人使用的一个方法, 直观, 方便, 但效率很低.
方法二: 比较字符串长度, 效率高, 是我知道的最好一个方法.
方法三: Java SE 6.0 才开始提供的方法, 效率和方法二几乎相等, 但出于兼容性考虑, 推荐使用方法二.

1：if(s == null || s.equals(""));

2：if(s == null || s.length() <= 0);

3：if(s == null || s.isEmpty());

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19 楼 akfucc 2010-01-24  
<div class="quote_title">xiaoyiz 写道</div>
<div class="quote_div">
<div class="quote_title">ronalke 写道</div>
<div class="quote_div">
<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span style="font-size: x-small;"><span>以下是</span><span lang="EN-US"><span style="font-family: Times New Roman;"> Java </span></span><span>判断字符串是否为空的三种方法</span></span><span style="font-size: x-small;"><span lang="EN-US"><span style="font-family: Times New Roman;">.<br></span></span><span>方法一</span><span lang="EN-US"><span style="font-family: Times New Roman;">: </span></span><span>最多人使用的一个方法</span><span lang="EN-US"><span style="font-family: Times New Roman;">, </span></span><span>直观</span><span lang="EN-US"><span style="font-family: Times New Roman;">, </span></span><span>方便</span><span lang="EN-US"><span style="font-family: Times New Roman;">, </span></span><span>但效率很低</span></span><span style="font-size: x-small;"><span lang="EN-US"><span style="font-family: Times New Roman;">.<br></span></span><span>方法二</span><span lang="EN-US"><span style="font-family: Times New Roman;">: </span></span><span>比较字符串长度</span><span lang="EN-US"><span style="font-family: Times New Roman;">, </span></span><span>效率高</span><span lang="EN-US"><span style="font-family: Times New Roman;">, </span></span><span>是我知道的最好一个方法</span></span><span style="font-size: x-small;"><span lang="EN-US"><span style="font-family: Times New Roman;">.<br></span></span><span>方法三</span><span lang="EN-US"><span style="font-family: Times New Roman;">: Java SE 6.0 </span></span><span>才开始提供的方法</span><span lang="EN-US"><span style="font-family: Times New Roman;">, </span></span><span>效率和方法二几乎相等</span><span lang="EN-US"><span style="font-family: Times New Roman;">, </span></span><span>但出于兼容性考虑</span><span lang="EN-US"><span style="font-family: Times New Roman;">, </span></span><span>推荐使用方法二</span><span style="font-family: Times New Roman;"><span lang="EN-US">.</span></span></span></p>
<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span style="font-size: x-small;"><span lang="EN-US"><span style="font-family: Times New Roman;">1</span></span><span>：</span><span lang="EN-US"><span style="font-family: Times New Roman;">if(s == null || s.equals(""));</span></span></span></p>
<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span style="font-size: x-small;"><span lang="EN-US"><span style="font-family: Times New Roman;">2</span></span><span>：</span><span lang="EN-US"><span style="font-family: Times New Roman;">if(s == null || s.length() &lt;= 0);</span></span></span></p>
<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span style="font-size: x-small;"><span lang="EN-US"><span style="font-family: Times New Roman;">3</span></span><span>：</span><span lang="EN-US"><span style="font-family: Times New Roman;">if(s == null || s.isEmpty());</span></span></span></p>
</div>
<p> </p>
<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span style="font-size: x-small;"><span style="background-color: #ffffff;"><span style="color: #0000ff;"><span lang="EN-US"><span style="font-family: Times New Roman;">1</span></span><span>：</span><span lang="EN-US"><span style="font-family: Times New Roman;">if(null==s || "".equals(s));</span></span></span></span></span></p>
<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span style="font-size: x-small;"><span style="background-color: #ffffff;"><span style="color: #0000ff;"><span lang="EN-US"><span style="font-family: Times New Roman;">2</span></span><span>：</span><span lang="EN-US"><span style="font-family: Times New Roman;">if(null==s  || 0&gt;=s.length()  );</span></span></span></span></span></p>
<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span style="font-size: x-small;"><span style="background-color: #ffffff;"><span style="color: #0000ff;"><span lang="EN-US"><span style="font-family: Times New Roman;">3</span></span><span>：</span><span lang="EN-US"><span style="font-family: Times New Roman;">if(null ==s  || s.isEmpty());</span></span></span></span></span></p>
<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"> </p>
<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span style="font-family: Times New Roman; color: #ff0000; font-size: x-small;"><span lang="EN-US">要反着写更安全，如果s本身为null 那么s.length直接抛出空指针一场了。。。 囧~</span></span></p>
</div>
<p> </p>
<p>无语，</p>
<p>String s= null;</p>
<p>if(s == null || s.length()==0){//...}</p>
<p>你别告诉我这会报错。。</p>
18 楼 wang_fei4321 2010-01-23  
为什么第一种方法性能低呢？
17 楼 belover 2010-01-23  
当然考虑性能没有什么不好！ 不过在这个层面考虑性能？效率上会有很大差异吗？
16 楼 nowopen 2010-01-23  
<div class="quote_title">xiaoyiz 写道</div>
<div class="quote_div">
<div class="quote_title">ronalke 写道</div>
<div class="quote_div">
<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span style="font-size: x-small;"><span>以下是</span><span lang="EN-US"><span style="font-family: Times New Roman;"> Java </span></span><span>判断字符串是否为空的三种方法</span></span><span style="font-size: x-small;"><span lang="EN-US"><span style="font-family: Times New Roman;">.<br></span></span><span>方法一</span><span lang="EN-US"><span style="font-family: Times New Roman;">: </span></span><span>最多人使用的一个方法</span><span lang="EN-US"><span style="font-family: Times New Roman;">, </span></span><span>直观</span><span lang="EN-US"><span style="font-family: Times New Roman;">, </span></span><span>方便</span><span lang="EN-US"><span style="font-family: Times New Roman;">, </span></span><span>但效率很低</span></span><span style="font-size: x-small;"><span lang="EN-US"><span style="font-family: Times New Roman;">.<br></span></span><span>方法二</span><span lang="EN-US"><span style="font-family: Times New Roman;">: </span></span><span>比较字符串长度</span><span lang="EN-US"><span style="font-family: Times New Roman;">, </span></span><span>效率高</span><span lang="EN-US"><span style="font-family: Times New Roman;">, </span></span><span>是我知道的最好一个方法</span></span><span style="font-size: x-small;"><span lang="EN-US"><span style="font-family: Times New Roman;">.<br></span></span><span>方法三</span><span lang="EN-US"><span style="font-family: Times New Roman;">: Java SE 6.0 </span></span><span>才开始提供的方法</span><span lang="EN-US"><span style="font-family: Times New Roman;">, </span></span><span>效率和方法二几乎相等</span><span lang="EN-US"><span style="font-family: Times New Roman;">, </span></span><span>但出于兼容性考虑</span><span lang="EN-US"><span style="font-family: Times New Roman;">, </span></span><span>推荐使用方法二</span><span style="font-family: Times New Roman;"><span lang="EN-US">.</span></span></span></p>
<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span style="font-size: x-small;"><span lang="EN-US"><span style="font-family: Times New Roman;">1</span></span><span>：</span><span lang="EN-US"><span style="font-family: Times New Roman;">if(s == null || s.equals(""));</span></span></span></p>
<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span style="font-size: x-small;"><span lang="EN-US"><span style="font-family: Times New Roman;">2</span></span><span>：</span><span lang="EN-US"><span style="font-family: Times New Roman;">if(s == null || s.length() &lt;= 0);</span></span></span></p>
<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span style="font-size: x-small;"><span lang="EN-US"><span style="font-family: Times New Roman;">3</span></span><span>：</span><span lang="EN-US"><span style="font-family: Times New Roman;">if(s == null || s.isEmpty());</span></span></span></p>
</div>
<p> </p>
<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span style="font-size: x-small;"><span style="background-color: #ffffff;"><span style="color: #0000ff;"><span lang="EN-US"><span style="font-family: Times New Roman;">1</span></span><span>：</span><span lang="EN-US"><span style="font-family: Times New Roman;">if(null==s || "".equals(s));</span></span></span></span></span></p>
<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span style="font-size: x-small;"><span style="background-color: #ffffff;"><span style="color: #0000ff;"><span lang="EN-US"><span style="font-family: Times New Roman;">2</span></span><span>：</span><span lang="EN-US"><span style="font-family: Times New Roman;">if(null==s  || 0&gt;=s.length()  );</span></span></span></span></span></p>
<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span style="font-size: x-small;"><span style="background-color: #ffffff;"><span style="color: #0000ff;"><span lang="EN-US"><span style="font-family: Times New Roman;">3</span></span><span>：</span><span lang="EN-US"><span style="font-family: Times New Roman;">if(null ==s  || s.isEmpty());</span></span></span></span></span></p>
<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"> </p>
<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span style="font-family: Times New Roman; color: #ff0000; font-size: x-small;"><span lang="EN-US">要反着写更安全，如果s本身为null 那么s.length直接抛出空指针一场了。。。 囧~</span></span></p>
</div>
<p> </p>
<p>
</p>
<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span style="font-size: x-small;"><span style="background-color: #ffffff;"><span style="color: #0000ff;"><span lang="EN-US"><span style="font-family: Times New Roman;">1</span></span><span>：</span><span lang="EN-US"><span style="font-family: Times New Roman;">if(null==s || "".equals(s));</span></span></span></span></span></p>
<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span style="font-size: x-small;"><span style="background-color: #ffffff;"><span style="color: #0000ff;"><span lang="EN-US"><span style="font-family: Times New Roman;">2</span></span><span>：</span><span lang="EN-US"><span style="font-family: Times New Roman;">if(null==s  || 0&gt;=s.length()  );</span></span></span></span></span></p>

<p>被你打败了！</p>
15 楼 vvggsky 2010-01-23  
<div class="quote_title">xiaoyiz 写道</div>
<div class="quote_div">
<div class="quote_title">ronalke 写道</div>
<div class="quote_div">
<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span style="font-size: x-small;"><span>以下是</span><span lang="EN-US"><span style="font-family: Times New Roman;"> Java </span></span><span>判断字符串是否为空的三种方法</span></span><span style="font-size: x-small;"><span lang="EN-US"><span style="font-family: Times New Roman;">.<br></span></span><span>方法一</span><span lang="EN-US"><span style="font-family: Times New Roman;">: </span></span><span>最多人使用的一个方法</span><span lang="EN-US"><span style="font-family: Times New Roman;">, </span></span><span>直观</span><span lang="EN-US"><span style="font-family: Times New Roman;">, </span></span><span>方便</span><span lang="EN-US"><span style="font-family: Times New Roman;">, </span></span><span>但效率很低</span></span><span style="font-size: x-small;"><span lang="EN-US"><span style="font-family: Times New Roman;">.<br></span></span><span>方法二</span><span lang="EN-US"><span style="font-family: Times New Roman;">: </span></span><span>比较字符串长度</span><span lang="EN-US"><span style="font-family: Times New Roman;">, </span></span><span>效率高</span><span lang="EN-US"><span style="font-family: Times New Roman;">, </span></span><span>是我知道的最好一个方法</span></span><span style="font-size: x-small;"><span lang="EN-US"><span style="font-family: Times New Roman;">.<br></span></span><span>方法三</span><span lang="EN-US"><span style="font-family: Times New Roman;">: Java SE 6.0 </span></span><span>才开始提供的方法</span><span lang="EN-US"><span style="font-family: Times New Roman;">, </span></span><span>效率和方法二几乎相等</span><span lang="EN-US"><span style="font-family: Times New Roman;">, </span></span><span>但出于兼容性考虑</span><span lang="EN-US"><span style="font-family: Times New Roman;">, </span></span><span>推荐使用方法二</span><span style="font-family: Times New Roman;"><span lang="EN-US">.</span></span></span></p>
<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span style="font-size: x-small;"><span lang="EN-US"><span style="font-family: Times New Roman;">1</span></span><span>：</span><span lang="EN-US"><span style="font-family: Times New Roman;">if(s == null || s.equals(""));</span></span></span></p>
<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span style="font-size: x-small;"><span lang="EN-US"><span style="font-family: Times New Roman;">2</span></span><span>：</span><span lang="EN-US"><span style="font-family: Times New Roman;">if(s == null || s.length() &lt;= 0);</span></span></span></p>
<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span style="font-size: x-small;"><span lang="EN-US"><span style="font-family: Times New Roman;">3</span></span><span>：</span><span lang="EN-US"><span style="font-family: Times New Roman;">if(s == null || s.isEmpty());</span></span></span></p>
</div>
<p> </p>
<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span style="font-size: x-small;"><span style="background-color: #ffffff;"><span style="color: #0000ff;"><span lang="EN-US"><span style="font-family: Times New Roman;">1</span></span><span>：</span><span lang="EN-US"><span style="font-family: Times New Roman;">if(null==s || "".equals(s));</span></span></span></span></span></p>
<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span style="font-size: x-small;"><span style="background-color: #ffffff;"><span style="color: #0000ff;"><span lang="EN-US"><span style="font-family: Times New Roman;">2</span></span><span>：</span><span lang="EN-US"><span style="font-family: Times New Roman;">if(null==s  || 0&gt;=s.length()  );</span></span></span></span></span></p>
<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span style="font-size: x-small;"><span style="background-color: #ffffff;"><span style="color: #0000ff;"><span lang="EN-US"><span style="font-family: Times New Roman;">3</span></span><span>：</span><span lang="EN-US"><span style="font-family: Times New Roman;">if(null ==s  || s.isEmpty());</span></span></span></span></span></p>
<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"> </p>
<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span style="font-family: Times New Roman; color: #ff0000; font-size: x-small;"><span lang="EN-US">要反着写更安全，如果s本身为null 那么s.length直接抛出空指针一场了。。。 囧~</span></span></p>
</div>
<p>误人子弟</p>
14 楼 YiSingQ 2010-01-23  
<div class="quote_title">xiaoyiz 写道</div>
<div class="quote_div">
<div class="quote_title">ronalke 写道</div>
<div class="quote_div">
<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span style="font-size: x-small;"><span>以下是</span><span lang="EN-US"><span style="font-family: Times New Roman;"> Java </span></span><span>判断字符串是否为空的三种方法</span></span><span style="font-size: x-small;"><span lang="EN-US"><span style="font-family: Times New Roman;">.<br></span></span><span>方法一</span><span lang="EN-US"><span style="font-family: Times New Roman;">: </span></span><span>最多人使用的一个方法</span><span lang="EN-US"><span style="font-family: Times New Roman;">, </span></span><span>直观</span><span lang="EN-US"><span style="font-family: Times New Roman;">, </span></span><span>方便</span><span lang="EN-US"><span style="font-family: Times New Roman;">, </span></span><span>但效率很低</span></span><span style="font-size: x-small;"><span lang="EN-US"><span style="font-family: Times New Roman;">.<br></span></span><span>方法二</span><span lang="EN-US"><span style="font-family: Times New Roman;">: </span></span><span>比较字符串长度</span><span lang="EN-US"><span style="font-family: Times New Roman;">, </span></span><span>效率高</span><span lang="EN-US"><span style="font-family: Times New Roman;">, </span></span><span>是我知道的最好一个方法</span></span><span style="font-size: x-small;"><span lang="EN-US"><span style="font-family: Times New Roman;">.<br></span></span><span>方法三</span><span lang="EN-US"><span style="font-family: Times New Roman;">: Java SE 6.0 </span></span><span>才开始提供的方法</span><span lang="EN-US"><span style="font-family: Times New Roman;">, </span></span><span>效率和方法二几乎相等</span><span lang="EN-US"><span style="font-family: Times New Roman;">, </span></span><span>但出于兼容性考虑</span><span lang="EN-US"><span style="font-family: Times New Roman;">, </span></span><span>推荐使用方法二</span><span style="font-family: Times New Roman;"><span lang="EN-US">.</span></span></span></p>
<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span style="font-size: x-small;"><span lang="EN-US"><span style="font-family: Times New Roman;">1</span></span><span>：</span><span lang="EN-US"><span style="font-family: Times New Roman;">if(s == null || s.equals(""));</span></span></span></p>
<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span style="font-size: x-small;"><span lang="EN-US"><span style="font-family: Times New Roman;">2</span></span><span>：</span><span lang="EN-US"><span style="font-family: Times New Roman;">if(s == null || s.length() &lt;= 0);</span></span></span></p>
<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span style="font-size: x-small;"><span lang="EN-US"><span style="font-family: Times New Roman;">3</span></span><span>：</span><span lang="EN-US"><span style="font-family: Times New Roman;">if(s == null || s.isEmpty());</span></span></span></p>
</div>
<p> </p>
<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span style="font-size: x-small;"><span style="background-color: #ffffff;"><span style="color: #0000ff;"><span lang="EN-US"><span style="font-family: Times New Roman;">1</span></span><span>：</span><span lang="EN-US"><span style="font-family: Times New Roman;">if(null==s || "".equals(s));</span></span></span></span></span></p>
<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span style="font-size: x-small;"><span style="background-color: #ffffff;"><span style="color: #0000ff;"><span lang="EN-US"><span style="font-family: Times New Roman;">2</span></span><span>：</span><span lang="EN-US"><span style="font-family: Times New Roman;">if(null==s  || 0&gt;=s.length()  );</span></span></span></span></span></p>
<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span style="font-size: x-small;"><span style="background-color: #ffffff;"><span style="color: #0000ff;"><span lang="EN-US"><span style="font-family: Times New Roman;">3</span></span><span>：</span><span lang="EN-US"><span style="font-family: Times New Roman;">if(null ==s  || s.isEmpty());</span></span></span></span></span></p>
<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"> </p>
<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span style="font-family: Times New Roman; color: #ff0000; font-size: x-small;"><span lang="EN-US">要反着写更安全，如果s本身为null 那么s.length直接抛出空指针一场了。。。 囧~</span></span></p>
</div>
<p>赞同反过来的写法，但是在遗留的就系统中一般采用第一种，现在是一般都在用isEmpty()咯。。。</p>
13 楼 yourfei 2010-01-23  
如果你使用了Spring，它里面也有StringUtils.hasText()
12 楼 xiaoyiz 2010-01-23  
<div class="quote_title">ronalke 写道</div>
<div class="quote_div">
<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span style="font-size: x-small;"><span>以下是</span><span lang="EN-US"><span style="font-family: Times New Roman;"> Java </span></span><span>判断字符串是否为空的三种方法</span></span><span style="font-size: x-small;"><span lang="EN-US"><span style="font-family: Times New Roman;">.<br></span></span><span>方法一</span><span lang="EN-US"><span style="font-family: Times New Roman;">: </span></span><span>最多人使用的一个方法</span><span lang="EN-US"><span style="font-family: Times New Roman;">, </span></span><span>直观</span><span lang="EN-US"><span style="font-family: Times New Roman;">, </span></span><span>方便</span><span lang="EN-US"><span style="font-family: Times New Roman;">, </span></span><span>但效率很低</span></span><span style="font-size: x-small;"><span lang="EN-US"><span style="font-family: Times New Roman;">.<br></span></span><span>方法二</span><span lang="EN-US"><span style="font-family: Times New Roman;">: </span></span><span>比较字符串长度</span><span lang="EN-US"><span style="font-family: Times New Roman;">, </span></span><span>效率高</span><span lang="EN-US"><span style="font-family: Times New Roman;">, </span></span><span>是我知道的最好一个方法</span></span><span style="font-size: x-small;"><span lang="EN-US"><span style="font-family: Times New Roman;">.<br></span></span><span>方法三</span><span lang="EN-US"><span style="font-family: Times New Roman;">: Java SE 6.0 </span></span><span>才开始提供的方法</span><span lang="EN-US"><span style="font-family: Times New Roman;">, </span></span><span>效率和方法二几乎相等</span><span lang="EN-US"><span style="font-family: Times New Roman;">, </span></span><span>但出于兼容性考虑</span><span lang="EN-US"><span style="font-family: Times New Roman;">, </span></span><span>推荐使用方法二</span><span style="font-family: Times New Roman;"><span lang="EN-US">.</span></span></span></p>
<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span style="font-size: x-small;"><span lang="EN-US"><span style="font-family: Times New Roman;">1</span></span><span>：</span><span lang="EN-US"><span style="font-family: Times New Roman;">if(s == null || s.equals(""));</span></span></span></p>
<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span style="font-size: x-small;"><span lang="EN-US"><span style="font-family: Times New Roman;">2</span></span><span>：</span><span lang="EN-US"><span style="font-family: Times New Roman;">if(s == null || s.length() &lt;= 0);</span></span></span></p>
<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span style="font-size: x-small;"><span lang="EN-US"><span style="font-family: Times New Roman;">3</span></span><span>：</span><span lang="EN-US"><span style="font-family: Times New Roman;">if(s == null || s.isEmpty());</span></span></span></p>
</div>
<p> </p>
<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span style="font-size: x-small;"><span style="background-color: #ffffff;"><span style="color: #0000ff;"><span lang="EN-US"><span style="font-family: Times New Roman;">1</span></span><span>：</span><span lang="EN-US"><span style="font-family: Times New Roman;">if(null==s || "".equals(s));</span></span></span></span></span></p>
<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span style="font-size: x-small;"><span style="background-color: #ffffff;"><span style="color: #0000ff;"><span lang="EN-US"><span style="font-family: Times New Roman;">2</span></span><span>：</span><span lang="EN-US"><span style="font-family: Times New Roman;">if(null==s  || 0&gt;=s.length()  );</span></span></span></span></span></p>
<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span style="font-size: x-small;"><span style="background-color: #ffffff;"><span style="color: #0000ff;"><span lang="EN-US"><span style="font-family: Times New Roman;">3</span></span><span>：</span><span lang="EN-US"><span style="font-family: Times New Roman;">if(null ==s  || s.isEmpty());</span></span></span></span></span></p>
<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span style="font-family: Times New Roman; font-size: x-small;"></span></p>
<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span style="font-family: Times New Roman; color: #ff0000; font-size: x-small;"><span lang="EN-US">要反着写更安全，如果s本身为null 那么s.length直接抛出空指针一场了。。。 囧~</span></span></p>
11 楼 zhangzhimin2008 2010-01-23  
一直用stringutils
10 楼 li445970924 2010-01-23  
方法2比较好 规范些
9 楼 ivan18248 2010-01-23  
一直用第一个看了楼主的用用二和三
8 楼 sorehead 2010-01-23  
7 楼 毕竟红尘 2010-01-23  
是common-lang里面的工具方法...
6 楼 liusu 2010-01-23  
给点测试数据？
5 楼 tsxm 2010-01-23  
我好像一直用方法一啊
4 楼 leon_a 2010-01-22  
魔力猫咪 写道
anky_end 写道
直接用stringutils的静态方法。。。

这是哪个静态方法，我查了半天JDK没发现。

apache.commons.lang
3 楼 魔力猫咪 2010-01-22  
anky_end 写道
直接用stringutils的静态方法。。。

这是哪个静态方法，我查了半天JDK没发现。
2 楼 xzqttt 2010-01-22  
一直在用方法3
没有必要细究这个吧
1 楼 anky_end 2010-01-22  
直接用stringutils的静态方法。。。
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