Detailed explanation of Java shallow and deep replication examples
1 The difference between shallow copy and deep copy
Shallow copy: Shallow copy just copy the original data type of this object, such as int, float, and String, and will not copy arrays and object references. Therefore shallow replication is risky.
Deep copy: Not only does it copy the original data type, it also copies the array and object references in the object, thereby achieving complete copying of the object.
2 Code Examples
package com;
import ;
public class Test implements Cloneable {
// Private attributes private ArrayList<String> nameList = new ArrayList<String>();
// Add content public void add(String s) {
(s);
}
// Get an ArrayList object public ArrayList<String> get() {
return ;
}
// clone method @Override
public Test clone() {
try {
Test test = (Test) ();
= (ArrayList<String>) (); //A
return test;
} catch (CloneNotSupportedException e) {
// TODO Auto-generated catch block
();
}
return null;
}
/**
* @param args
*/
public static void main(String[] args) {
// Create a test object Test test = new Test();
// Set the content of the test object ("aa");
("bb");
// Print and display the nameList content in the test ("test:" + ());
//Clone the test object to generate the test2 object Test test2 = ();
// Add "cc" content to test2 object ("cc");
// Print and display the nameList content in test2 ("test2:" + ());
// Print and display the nameList content in the test ("test:" + ());
}
}
3 shallow copy run results
test:[aa, bb] test2:[aa, bb, cc] test:[aa, bb, cc]
4 Deep copy run results
test:[aa, bb] test2:[aa, bb, cc] test:[aa, bb]
5 Results Analysis
From the perspective of result analysis and code, deep copy only has more code at A for shallow copy.
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