Java 数组复制clone方法实现详解
这篇文章主要介绍了Java 数组复制clone方法实现详解,文中通过示例代码介绍的非常详细,对大家的学习或者工作具有一定的参考学习价值,需要的朋友可以参考下
一、源码
public class Test1 {
public static void main(String[] args) {
// Student[] arrs = new Student[] { new Student() { id = "22" } }; C# 可以简写法,Java不支持
Student[] arrs = new Student[1];
Student st = new Student();
st.id = 12;
st.name = "qwe";
arrs[0] = st;
Student[] arrss = arrs.clone();
System.out.println(arrs == arrss);
System.out.println(arrs.equals(arrss));
arrss[0].id = 56;
for (int i = 0; i < arrs.length; i++) {
System.out.println(arrs[i].id + arrs[i].name);
}
for (int i = 0; i < arrss.length; i++) {
System.out.println(arrss[i].id + arrss[i].name);
}
System.out.println("-------------自定义对象类型数组clone-------------");
Student[] arrst1 = new Student[1];
Student st1 = new Student();
st1.id = 162;
st1.name = "qkkj";
arrst1[0] = st1;
Student[] arrst2 = arrst1;
System.out.println(arrst1 == arrst2);
System.out.println(arrst1.equals(arrst2));
arrst2[0].id = 996;
for (int i = 0; i < arrst1.length; i++) {
System.out.println(arrst1[i].id + arrst1[i].name);
}
for (int i = 0; i < arrst2.length; i++) {
System.out.println(arrst2[i].id + arrst2[i].name);
}
System.out.println("-------------自定义对象类型数组= 赋值-------------");
var arr1 = new String[] { "we", "dfeffg" };
var arr = arr1.clone();
System.out.println(arr1 == arr);
System.out.println(arr1.equals(arr));
arr[1] = "ddddddddddddddd";
for (int i = 0; i < arr.length; i++) {
System.out.println(arr[i]);
}
for (int i = 0; i < arr1.length; i++) {
System.out.println(arr1[i]);
}
System.out.println("------------字符串数组clone--------------");
var arr11 = new String[] { "we", "dfeffg" };
var arr111 = arr11;
System.out.println(arr111 == arr11);
System.out.println(arr111.equals(arr11));
arr111[1] = "ddddddddddddddd";
for (int i = 0; i < arr11.length; i++) {
System.out.println(arr11[i]);
}
for (int i = 0; i < arr111.length; i++) {
System.out.println(arr111[i]);
}
System.out.println("------------字符串数组=赋值--------------");
var arr2 = new int[] { 232, 45 };
var arr3 = arr2.clone();
System.out.println(arr2 == arr3);
System.out.println(arr2.equals(arr3));
arr3[1] = 4444;
for (int i = 0; i < arr2.length; i++) {
System.out.println(arr2[i]);
}
for (int i = 0; i < arr3.length; i++) {
System.out.println(arr3[i]);
}
System.out.println("------------数字类型数组clone--------------");
var arr4 = new int[] { 23432, 44455 };
var arr5 = arr4;
System.out.println(arr4 == arr5);
System.out.println(arr4.equals(arr5));
arr4[1] = 6666;
for (int i = 0; i < arr4.length; i++) {
System.out.println(arr4[i]);
}
for (int i = 0; i < arr5.length; i++) {
System.out.println(arr5[i]);
}
System.out.println("------------数字类型数组=赋值-----------------");
}
}
class Student {
public int id;
public String name;
}
二、运行结果
false
false
56qwe
56qwe
-------------自定义对象类型数组clone-------------
true
true
996qkkj
996qkkj
-------------自定义对象类型数组= 赋值-------------
false
false
we
ddddddddddddddd
we
dfeffg
------------字符串数组clone--------------
true
true
we
ddddddddddddddd
we
ddddddddddddddd
------------字符串数组=赋值--------------
false
false
45
4444
------------数字类型数组clone--------------
true
true
6666
6666
------------数字类型数组=赋值-----------------
三、结果分析
1.clone复制,对于数组本身而言,它的元素是引用类型(字符串除外)的时候,本来数组每个元素中保存的就是对象的引用,所以,拷贝过来的数组自然而言也是对象的引用,所以对于数组对象元素而言,它又是浅拷贝;
2.clone复制,对于引用类型(字符串除外),改变其中一个中的值,会影响另外一个值,相当于“浅拷贝”;
3.clone复制,对于值类型、字符串,改变其中一个中的值,不会影响另外一个值,相当于“深拷贝”;
4.等号复值后修改一个后会影响另一个
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