null值的处理代码,Java代码库,德仔网

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【Java】 null值的处理
作者: / 发布于2011/1/14/ 576
<div><span style="color: #008000">/**</span><span style="color: #008000">
 * 如果是null，则返回空字符串，如果是非空值则返回该字符串头尾不为空白字符的字符串
 * 
 * </span><span style="color: #808080">@param</span><span style="color: #008000"> str
 </span><span style="color: #008000">*/</span><span style="color: #000000">
 </span><span style="color: #0000ff">public</span><span style="color: #000000"> </span><span style="color: #0000ff">static</span><span style="color: #000000"> String toNoNullTrimedString(String str) {
 </span><span style="color: #0000ff">if</span><span style="color: #000000"> (str </span><span style="color: #000000">==</span><span style="color: #000000"> </span><span style="color: #0000ff">null</span><span style="color: #000000">) {
 </span><span style="color: #0000ff">return</span><span style="color: #000000"> </span><span style="color: #000000">""</span><span style="color: #000000">;
 }
 </span><span style="color: #0000ff">return</span><span style="color: #000000"> </span><span style="color: #0000ff">new</span><span style="color: #000000"> String(str.trim());
 }
 
 </span><span style="color: #008000">/**</span><span style="color: #008000">
* 如果是null，则返回空字符串，如果是非空值则返回该对象所toString后的字符串
*
* </span><span style="color: #808080">@param</span><span style="color: #008000"> obj
 </span><span style="color: #008000">*/</span><span style="color: #000000">
 </span><span style="color: #0000ff">public</span><span style="color: #000000"> </span><span style="color: #0000ff">static</span><span style="color: #000000"> String toNoNullString(Object obj) {
 </span><span style="color: #0000ff">if</span><span style="color: #000000"> (obj </span><span style="color: #000000">==</span><span style="color: #000000"> </span><span style="color: #0000ff">null</span><span style="color: #000000">)
 </span><span style="color: #0000ff">return</span><span style="color: #000000"> </span><span style="color: #000000">""</span><span style="color: #000000">;
 </span><span style="color: #0000ff">return</span><span style="color: #000000"> obj.toString();
 }

 </span><span style="color: #008000">/**</span><span style="color: #008000">
 * 本方法把一个Throwable的StackTrace作为一个字符串输出，以利于对StackTrace的操作。
 * 通常用于把抛出的Exception转化成字符串进行后续操作。
 </span><span style="color: #008000">*/</span><span style="color: #000000">
 </span><span style="color: #0000ff">public</span><span style="color: #000000"> </span><span style="color: #0000ff">static</span><span style="color: #000000"> String exceptionToStackTrace(Throwable throwable) {
 StringBuffer retu </span><span style="color: #000000">=</span><span style="color: #000000"> </span><span style="color: #0000ff">new</span><span style="color: #000000"> StringBuffer();
 StackTraceElement[] traces </span><span style="color: #000000">=</span><span style="color: #000000"> throwable.getStackTrace();
 </span><span style="color: #0000ff">for</span><span style="color: #000000"> (StackTraceElement ste : traces) {
 retu.append(</span><span style="color: #000000">"</span><span style="color: #000000">\n</span><span style="color: #000000">"</span><span style="color: #000000">).append(ste.toString());
 }
 </span><span style="color: #0000ff">return</span><span style="color: #000000"> retu.substring(</span><span style="color: #000000">1</span><span style="color: #000000">);
 }
</span>
</div>
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