publicclassArraycopyTest{publicstaticvoidmain(String[] args){// TODO Auto-generated method stubint[] a =newint[10]; a[0] =0; a[1] =1; a[2] =2; a[3] =3; System.arraycopy(a,2, a,3,3); a[2]=99;for(inti=0; i < a.length; i++) { System.out.println(a[i]); } }...
实例代码：importjava.util.Arrays;//Array.copyOf拷贝数组publicclassKaoBei4{publicstaticvoidmain(String...
System.arraycopy() （以及相关的 java.util.Arrays.copyOf() ）都会被实现为intrinsic method，JVM内...
arraycopy 方法会因为新数组大小比久数组大小小而报IndexOutOfBoundsException copyOf 则不会因此报错,因为copyOf 的返回值是在内部new 好的copy 数组,而该copy 数组new 的大小就等于newLength 故即使在客户端指定好了新数组newArray 的大小,接收到返回值后也是指向底层new 出来的数组copy 。换句话说( 也可以因此推...
static JNINativeMethod methods[] = { {"currentTimeMillis", "()J", (void *)&JVM_CurrentTimeMillis}, {"nanoTime", "()J", (void *)&JVM_NanoTime}, {"arraycopy", "(" OBJ "I" OBJ "II)V", (void *)&JVM_ArrayCopy}, }; ...
该方法被声明为native，最初似乎需要通过JNI调用JVM中的本地代码实现。然而，高性能JVM中，System.arraycopy()和相关方法java.util.Arrays.copyOf()都被实现为intrinsic method，进行特殊优化。HotSpot VM在编译时根据参数类型和常量值判断，调用高度优化的汇编实现的stub，充分利用当前CPU的SIMD指令提高速度...
1、先来看看基本数据类型的System.arraycopy() 方法拷贝: 1importjava.util.Arrays;2publicclassTestDemo {3publicstaticvoidmain(String[] args) {45int[] array1 =newint[]{1,2,8,7,6};6int[] array2 =newint[array1.length];7System.arraycopy(array1, 0, array2, 0, array1.length);89System...
The arraycopy() method can be used to copy quickly an array of any type from one place to another. This is much faster than the equivalent loop written out longhand in Java. Here is an example of two arrays being copied by the arraycopy() method. First,
要理解一下arraycopy方法的参数：arraycopy(Object src, int srcPos, Object dest, int destPos, int length);1、源和目标对象都必须是数组 2、srcPos和destPos都必须保证不越界 3、目标对象可写
When the array is initialized, the length of the array is immutable. The exp... XieXiyu 0 195 JAVA克隆对象报错:The method clone() from the type Object is not visible 2019-12-07 20:22 − 将一个对象复制一份,称为对象的克隆技术。在Object类汇总存在一个clone()方法:protected Onject ...