Java中的對象拷貝方式有兩種：深拷貝和淺拷貝。深拷貝和淺拷貝在實現上都是將一個對象的值拷貝給另一個對象，但是兩者之間有著本質上的區別。

淺拷貝（Shallow Copy)，是指復制對象時，只是將對象的引用地址所指向的內存區域復制給一個新的對象。這種方式只復制對象本身，而不復制對象所引用的其他對象。即原始對象和拷貝對象只是簡單地引用同一個對象，修改其中一個對象的屬性值會影響另一個對象，所以淺拷貝拷貝的是指針，而不是內存中的內容。

public class Person {
private String name;
private int age;
public Person(String name, int age) {
this.name = name;
this.age = age;
}
public void setAge(int age) {
this.age = age;
}
public int getAge() {
return age;
}
public void setName(String name) {
this.name = name;
}
public String getName() {
return name;
}
public Person clone() {
try {
return (Person) super.clone();
} catch (CloneNotSupportedException e) {
e.printStackTrace();
return null;
}
}
}
Person p1 = new Person("Tom", 18);
Person p2 = p1.clone();  // 淺拷貝
p1.setAge(20);
System.out.println(p1.getAge());  // 20
System.out.println(p2.getAge());  // 20

深拷貝（Deep Copy），是指完全復制一份數據到另一塊內存區，兩個對象完全獨立，互不干擾。深拷貝不僅需要復制本身的對象，同時也要復制所引用的對象。即當對象中引用其他對象時，深拷貝將遞歸地拷貝整個對象樹。

public class Person implements Cloneable {
private String name;
private int age;
private Address address;
public Person(String name, int age, Address address) {
this.name = name;
this.age = age;
this.address = address;
}
public void setAge(int age) {
this.age = age;
}
public int getAge() {
return age;
}
public void setName(String name) {
this.name = name;
}
public String getName() {
return name;
}
public Address getAddress() {
return address;
}
public void setAddress(Address address) {
this.address = address;
}
@Override
public Person clone() {
try {
Person person = (Person) super.clone();
person.address = this.address.clone();
return person;
} catch (CloneNotSupportedException e) {
e.printStackTrace();
return null;
}
}
}
public class Address implements Cloneable {
private String province;
private String city;
public Address(String province, String city) {
this.province = province;
this.city = city;
}
public void setProvince(String province) {
this.province = province;
}
public String getProvince() {
return province;
}
public void setCity(String city) {
this.city = city;
}
public String getCity() {
return city;
}
@Override
public Address clone() {
try {
return (Address) super.clone();
} catch (CloneNotSupportedException e) {
e.printStackTrace();
return null;
}
}
}
Address address = new Address("江蘇省", "南京市");
Person person1 = new Person("Tom", 18, address);
Person person2 = person1.clone();  // 深拷貝
person1.setAge(20);
address.setProvince("北京市");
System.out.println(person1.getAge());  // 20
System.out.println(person1.getAddress().getProvince());  // 北京市
System.out.println(person2.getAge());  // 18
System.out.println(person2.getAddress().getProvince());  // 江蘇省