public void methodA(Object arg1) { methodB(arg1, new Object[0]); } public void methodB(Object arg1, Object[] arg2) { for (Object obj : arg2) {} // no null check } 如果函数的返回值是集合类型,当结果为空时,不要返回 null 值,而是返回一个空的集合;如果返回值类型是对象,则可以选择抛...
In object-oriented computer programming, a null object is an object with no referenced value or with defined neutral ("null") behavior. The null object design pattern describes the uses of such objects and their behavior (or lack thereof). 以上解析来自Wikipedia。 NullObject模式首次发表在“ 程序...
privateBooleancheckObjectAllNull(Objectobject)throws IllegalAccessException{Class<?>clz=object.getClass();Field[]declaredFields=clz.getDeclaredFields();Boolean flag=true;for(Field field:declaredFields){field.setAccessible(true);if(field.get(object)!=null){returnfalse;}}returntrue;} @Testpublicvoidtest...
In the real world, programmers find it hard to identify which objects can benull.An aggressively safe strategy could be to checknullfor every object. However, this causes a lot of redundantnullchecks and makes our code less readable. In the next few sections, we’ll go through some of the...
*@return*/publicbooleanobjCheckIsNull(Object object){ Class clazz= (Class)object.getClass();//得到类对象Field fields[] = clazz.getDeclaredFields();//得到所有属性booleanflag =true;//定义返回结果,默认为truefor(Field field : fields){
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通常我们在 public Set 时,如果没有特殊说明,返回的set 是不能为 null 的。所以严格的说,返回是否为空,我们需要判断,因为可能会出现问题。 先我们来看下面代码,对于这样的对象为空的检查: if (someobject != null) { someobject.doCalc(); }
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publicvoidtestGuava(Object arg){Object checked=Preconditions.checkNotNull(arg,"%s must not be null","arg");checked.toString();} 我们还可以使用Lombok来生成空值检测代码,并抛出带有提示信息的空指针异常: 代码语言:javascript 复制 publicvoidtestLombok(@NonNull Object arg){arg.toString();} ...
obj Object the object reference to check for nullity Returns Object obj if not null Attributes RegisterAttribute JavaTypeParametersAttribute Remarks Checks that the specified object reference is not null. This method is designed primarily for doing parameter validation in methods and constructors, ...