test只是刚刚在堆上分配的Test对象的引用,而这里的赋值直接是引用直接的赋值,等于test2也是指向刚刚new出来的对象,这里的copy就是一个shallow copy,及只是copy了一份引用,但是对象实体并未copy,既然赋值不行,那就试试第二个方法,Object类的clone方法。
下面ArrayList里的clone()就是一个浅层拷贝的方法 ArrayLista=newArrayList();a.add(1);a.add(2)ArrayListb=(ArrayList)a.clone();System.out.println(a.get(0));//print 1System.out.println(b.get(0));//print 1a.set(0,10000);System.out.println(a.get(0));//print 10000System.out.println(b...
java deep copy //deep copy 1、可以对每个成员变量赋值的方式重新将对象的成员值指向新的地址值(比如string),不能整个对象一起赋值(=),这样是引用了对象的地址值,修改应用对象时,被引用的也修改了 2、 使用工具类 BeanUtils.copyProperties(pifuList1.get(i),bpStation); List<BpStation> pifuList = new ...
1. UsingArrayList.clone()for Shallow Copy Theclone()method creates a newArrayListand thencopies the backing array to cloned array. It creates a shallow copy of the given arraylist. In a shallow copy, the original list and the cloned list, both refer to the same objects in the memory. Let...
java 中列表的赋值的问题。 这个问题核心是deep copy&shallow copy的问题 2. 情景再现 publicclassMikeTest{publicstaticvoidmain(String[]args)throws NoSuchMethodException{classPerson{privateStringname;privateIntegerage;Person(Stringname,Integerage){this.name=name;this.age=age;}}// TODO: 2022/3/8 测试一...
importjava.util.ArrayList;importjava.util.List;publicclassMain{publicstaticvoidmain(String[]args){List<String>list1=newArrayList<>();list1.add("apple");list1.add("banana");list1.add("cherry");List<String>list2=DeepCopyUtil.deepCopy(list1);System.out.println("Original list1: "+list1);Sy...
1System.arraycopy(Object src,intsrcPos, Object dest,intdestPos,intlength) 例如ArrayList中的clone()、Arrays.copyOf()等对具体数组的clone其实底层都是调用该方法。 验证Shallow Clone 深克隆(deep clone) jdk中并没有显式定义深克隆,或者说并没有直接提供工具类来进行。要让你的自定义类支持深克隆,必须具备...
1 Create an independent copy of an array 0 How to loop through a Map and clone each value? 1 How to deep copy an object in java. The object may or may not be serializable 1 Problem with copying a single item of an ArrayList 0 java - how to do deep copy of hashmap -3 Ta...
copy () 是深克隆还是浅克隆;以及深刻龙的几种实现方式。希望对你有帮助~ 7. 36630 ArrayList 其实也有双胞胎,但区别还是挺大的! 一、问题产生今天在学习ArrayList源码的时候发现了这么一句注释,即: c.toArray might (incorrectly) not return Object[] (see 6260652...extends T[]> newType) { // 在...
Because in kotlin, ArrayList.map {it.copy} not copying all items of an object specially if a member is list of another object inside this. The only solution, for deep copying of all items of an object I found on the web, is to serialize and deserialize the object when you send or ...