markdown 在java中复制构造函数和clone（）

Posted 2021-05-06

# Copy Constructor and `clone()` in java

*SOURCE:* [StackOverflow](https://stackoverflow.com/a/869078/1602807), [dzone](https://dzone.com/articles/java-cloning-copy-constructor-vs-cloning)

`clone()` and `Cloneable` interface in java could be tedious and has some issues. So in order to deep clone and object we can provide a simple copy constructor:

```java
class DummyBean {
  private String dummy;
  private Matrix matrix;
  
  public DummyBean(){} //default constructor

  //copy constructor, use this to clone
  public DummyBean(DummyBean another) {
    this.dummy = another.getDummy(); // String is already immutable
	this.matrix = new Matrix(another.getMatrix()); //deep copy
  }
  
  public String getDummy() {
	return dummy;
  }
  
  public Matrix getMatrix() {
	return matrix;
  }
}
```