@SuppressWarnings的使用、作用、用法

在Java编译过程中会出现很多警告，有很多是安全的，但是每次编译有很多警告影响我们对error的过滤和修改，我们可以在代码中加上

@SuppressWarnings(“XXXX”) 来解决

例如：@SuppressWarnings("deprecation")表示不显示使用了不赞成使用的类或方法时的警告；

（“xxx”）里面的参数有如下几种：

• all to suppress all warnings
• boxing to suppress warnings relative to boxing/unboxing operations
• cast to suppress warnings relative to cast operations
• dep-ann to suppress warnings relative to deprecated annotation
• deprecation to suppress warnings relative to deprecation
• fallthrough to suppress warnings relative to missing breaks in switch statements
• finally to suppress warnings relative to finally block that don’t return
• hiding to suppress warnings relative to locals that hide variable
• incomplete-switch to suppress warnings relative to missing entries in a switch statement (enum case)
• nls to suppress warnings relative to non-nls string literals
• null to suppress warnings relative to null analysis
• rawtypes to suppress warnings relative to un-specific types when using generics on class params
• restriction to suppress warnings relative to usage of discouraged or forbidden references
• serial to suppress warnings relative to missing serialVersionUID field for a serializable class
• static-access to suppress warnings relative to incorrect static access
• synthetic-access to suppress warnings relative to unoptimized access from inner classes
• unchecked to suppress warnings relative to unchecked operations
• unqualified-field-access to suppress warnings relative to field access unqualified
• unused to suppress warnings relative to unused code
• 例如：

@SuppressWarnings("serial")@WebServlet(name="ajax",urlPatterns="/servlet/ajax")public class ajax extends HttpServlet {   public void init() throws ServletException {}   protected void doGet(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException {   doActionPage(request, response);   }   protected void doPost(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException {   doActionPage(request, response);   }   public static Object execMethod(String classNameAndMethod, String  inputVal)   throws Exception{ int lastPoint = Util.NVLL(classNameAndMethod).lastIndexOf("."); inputVal = Util.NVLL(inputVal); if(lastPoint < 0)   return inputVal; try { String className = classNameAndMethod.substring(0, lastPoint); String methodName = classNameAndMethod.substring(lastPoint+1); int firstPa = methodName.indexOf("("); if(firstPa >0)   methodName = methodName.substring(0, firstPa);  Class clazzxxx = Class.forName(className);   if(inputVal.length() < 1) { java.lang.reflect.Method m = clazzxxx.getDeclaredMethod(methodName,  new Class[] {}); return m.invoke((Object) null, new Object[0]);  }  else { java.lang.reflect.Method m = clazzxxx.getDeclaredMethod(methodName, new Class[] {String.class}); return m.invoke(null, inputVal);  } } catch (Exception r) { Log.log("ERROR: ajax:" + classNameAndMethod + ", input value="  + inputVal); r.printStackTrace(); throw r; }...}