Java中的拷貝分為深拷貝和淺拷貝，兩者實現的方法有所不同：

淺拷貝

淺拷貝是指在拷貝對象時，只復制對象的基本數據類型、對象引用等，而不拷貝引用指向的對象或元素。實現淺拷貝有以下兩種方法：

1.使用Object類的clone方法

public class Test implements Cloneable {
private int id;
private Listlist;
public Test(int id, Listlist) {
this.id = id;
this.list = list;
}
public Object clone() {
Test o = null;
try {
o = (Test) super.clone();
} catch (CloneNotSupportedException e) {
e.printStackTrace();
}
return o;
}
}

2.使用Copy構造方法

public class Test {
private int id;
private Listlist;
public Test(Test t) {
this.id = t.id;
this.list = t.list;
}
}

深拷貝

深拷貝是指在拷貝對象時，會遞歸地拷貝對象引用指向的對象或元素。實現深拷貝有以下兩種方法：

1.使用Java序列化和反序列化

public class Test implements Serializable {
private int id;
private Listlist;
public Test(int id, Listlist) {
this.id = id;
this.list = list;
}
public Object deepClone() throws IOException, ClassNotFoundException {
ByteArrayOutputStream bo = new ByteArrayOutputStream();
ObjectOutputStream oo = new ObjectOutputStream(bo);
oo.writeObject(this);
ByteArrayInputStream bi = new ByteArrayInputStream(bo.toByteArray());
ObjectInputStream oi = new ObjectInputStream(bi);
return oi.readObject();
}
}

2.使用自定義方法遞歸拷貝對象引用指向的對象或元素

public class Test {
private int id;
private Listlist;
public Test deepClone() {
Test o = new Test(this.id, new ArrayList<>());
for (String s : this.list) {
o.list.add(s);
}
return o;
}
}