// 空对象模式示例interfaceAnimal{voidmakeSound();}classDogimplementsAnimal{publicvoidmakeSound(){System.out.println("Woof");}}classNullAnimalimplementsAnimal{publicvoidmakeSound(){// do nothing}}// 用法publicclassNullObjectPatternExample{publicstaticvoidmain(String[]args){Animalanimal=getAnimal("cat"...
.registerTypeAdapter(LocalDate.class, (JsonDeserializer<LocalDate>) (json, type, jsonDeserializationContext) ->LocalDate.parse(json.getAsJsonPrimitive().getAsString(), DateTimeFormatter.ofPattern("yyyy-MM-dd"))).create();for(SearchHit hit : searchHits) { String sourceAsString=hit.getSourceAsStri...
publicclassCalculatorInvocationHandlerimplementsInvocationHandler{privatefinalObjectobject;publicCalculatorInvocationHandler(Objectobject) {this.object=object; }@OverridepublicObjectinvoke(Objectproxy,Methodmethod,Object[] args) throwsThrowable{System.out.println("方法执行前:");Objectresult = method.invoke(object, ar...
The signature only tells you that it returns an object of type Admission. As discussed above, null corresponds to every type. Unless we analyze the implementation of the method, we have no way to know if null is returned. In contrast, a method returning an Optional looks like this. 签名仅...
public Stream<String> collectionToStream(Collection<String> collection) { return Optional.ofNullable(collection) .map(Collection::stream) .orElseGet(Stream::empty); } Optional.ofNullable(collection)creates anOptionalobject from the passed-in collection. An emptyOptionalobject is created if the collection...
处理MetaDataProvider时会调用ClassHierarchyHelper.getHierarchy( beanClass )方法,不仅仅处理本类。拿到本类自己和所有父类后,统一交给provider.getBeanConfiguration( clazz )处理(也就是说任何一个类都会把Object类处理一遍) retrieveBeanConfiguration()详情
public Object invoke(Object proxy, Method method, Object[] args) throws Throwable { System.out.println("welcome"); return method.invoke(originalObj, args); } } public static void main(String[] args) { IHello hello = (IHello) new DynamicProxy().bind(new Hello()); hello.sayHello(); }...
result = prime * result + ((type ==null) ?0: type.hashCode());returnresult; }@Overridepublicbooleanequals(Object obj){if(this== obj)returntrue;if(obj ==null)returnfalse;if(getClass() != obj.getClass())returnfalse;MyClassBother=(MyClassB) obj;if(elementname ==null) {if(other.ele...
其中的set(Object obj, Object value)方法是Field类本身的方法,用于设置字段的值,而get(Object obj)则是获取字段的值,当然关于Field类还有其他常用的方法如下:
public Class findClass(String keyString) { for (int i = 0; i < buckets.length; i++) { Entry bucket = buckets[i]; if (bucket == null) { continue; } for (Entry<K, V> entry = bucket; entry != null; entry = entry.next) { Object key = bucket.key; if (key instanceof Class...