史上最全Java面试题整理（附参考答案）

}
<span class="hljs-keyword">catch (Exception e) {
<span class="hljs-keyword">throw <span class="hljs-keyword">new RuntimeException(e);
}
}

<span class="hljs-comment">/**

• 通过反射给对象的指定字段赋值

• <span class="hljs-doctag">@param target 目标对象

• <span class="hljs-doctag">@param fieldName 字段的名称

• <span class="hljs-doctag">@param value 值
  */
  <span class="hljs-function"><span class="hljs-keyword">public <span class="hljs-keyword">static <span class="hljs-keyword">void <span class="hljs-title">setValue<span class="hljs-params">(Object target,Object value) {
  Class<?> clazz = target.getClass();
  String[] fs = fieldName.split(<span class="hljs-string">".");
  <span class="hljs-keyword">try {
  <span class="hljs-keyword">for(<span class="hljs-keyword">int i = <span class="hljs-number">0; i < fs.length - <span class="hljs-number">1; i++) {
  Field f = clazz.getDeclaredField(fs[i]);
  f.setAccessible(<span class="hljs-keyword">true);
  Object val = f.get(target);
  <span class="hljs-keyword">if(val == <span class="hljs-keyword">null) {
  Constructor<?> c = f.getType().getDeclaredConstructor();
  c.setAccessible(<span class="hljs-keyword">true);
  val = c.newInstance();
  f.set(target,val);
  }
  target = val;
  clazz = target.getClass();
  }

   Field f = clazz.getDeclaredField(fs[fs.length - <span class="hljs-number"&gt;1]);
   f.setAccessible(<span class="hljs-keyword"&gt;true);
   f.set(target,value);

  }
  <span class="hljs-keyword">catch (Exception e) {
  <span class="hljs-keyword">throw <span class="hljs-keyword">new RuntimeException(e);
  }
  }

}

<span class="cke_reset cke_widget_drag_handler_container"><img class="cke_reset cke_widget_drag_handler" title="点击并拖拽以移动" src="data:image/gif;base64,R0lGODlhAQABAPABAP///wAAACH5BAEKAAAALAAAAAABAAEAAAICRAEAOw==" alt="" width="15" height="15" data-cke-widget-drag-handler="1">

88、如何通过反射调用对象的方法？

答：请看下面的代码：

<span class="hljs-function"&gt;<span class="hljs-keyword"&gt;public <span class="hljs-keyword"&gt;static <span class="hljs-keyword"&gt;void <span class="hljs-title"&gt;main<span class="hljs-params"&gt;(String[] args) <span class="hljs-keyword"&gt;throws Exception {
    String str = <span class="hljs-string"&gt;"hello";
    Method m = str.getClass().getMethod(<span class="hljs-string"&gt;"toUpperCase");
    System.out.println(m.invoke(str));  <span class="hljs-comment"&gt;// HELLO
}