一、拷贝的引入
（1）、引用拷贝
创建一个指向对象的引用变量的拷贝。
Teacher teacher = new Teacher("Taylor",26); Teacher otherteacher = teacher; System.out.println(teacher); System.out.println(otherteacher);
输出结果：
blog.Teacher@355da254 blog.Teacher@355da254
结果分析：由输出结果可以看出，它们的地址值是相同的，那么它们肯定是同一个对象。teacher和otherteacher的只是引用而已，他们都指向了一个相同的对象Teacher(“Taylor”,26)。这就叫做引用拷贝。
（2）、对象拷贝
创建对象本身的一个副本。
Teacher teacher = new Teacher("Swift",26); Teacher otherteacher = (Teacher)teacher.clone(); System.out.println(teacher); System.out.println(otherteacher);
输出结果：
blog.Teacher@355da254 blog.Teacher@4dc63996
注：深拷贝和浅拷贝都是对象拷贝
二、浅拷贝
（1）、定义
被复制对象的所有变量都含有与原来的对象相同的值，而所有的对其他对象的引用仍然指向原来的对象。即对象的浅拷贝会对“主”对象进行拷贝，但不会复制主对象里面的对象。”里面的对象“会在原来的对象和它的副本之间共享。
简而言之，浅拷贝仅仅复制所考虑的对象，而不复制它所引用的对象
（2）、浅拷贝实例
package com.test; public class ShallowCopy { public static void main(String[] args) throws CloneNotSupportedException { Teacher teacher = new Teacher(); teacher.setName("riemann"); teacher.setAge(27); Student2 student1 = new Student2(); student1.setName("edgar"); student1.setAge(18); student1.setTeacher(teacher); Student2 student2 = (Student2) student1.clone(); System.out.println("拷贝后"); System.out.println(student2.getName()); System.out.println(student2.getAge()); System.out.println(student2.getTeacher().getName()); System.out.println(student2.getTeacher().getAge()); System.out.println("修改老师的信息后-------------"); // 修改老师的信息 teacher.setName("Games"); System.out.println(student1.getTeacher().getName()); System.out.println(student2.getTeacher().getName()); } } class Teacher implements Cloneable { private String name; private int age; public String getName() { return name; } public void setName(String name) { this.name = name; } public int getAge() { return age; } public void setAge(int age) { this.age = age; } } class Student2 implements Cloneable { private String name; private int age; private Teacher teacher; public String getName() { return name; } public void setName(String name) { this.name = name; } public int getAge() { return age; } public void setAge(int age) { this.age = age; } public Teacher getTeacher() { return teacher; } public void setTeacher(Teacher teacher) { this.teacher = teacher; } public Object clone() throws CloneNotSupportedException { Object object = super.clone(); return object; } }
输出结果：
拷贝后 edgar 18 riemann 27 修改老师的信息后------------- Games Games
结果分析：两个引用student1和student2指向不同的两个对象，但是两个引用student1和student2中的两个teacher引用指向的是同一个对象，所以说明是浅拷贝。
三、深拷贝
（1）、定义
深拷贝是一个整个独立的对象拷贝，深拷贝会拷贝所有的属性,并拷贝属性指向的动态分配的内存。当对象和它所引用的对象一起拷贝时即发生深拷贝。深拷贝相比于浅拷贝速度较慢并且花销较大。
简而言之，深拷贝把要复制的对象所引用的对象都复制了一遍。
（2）、深拷贝实例
package com.test; public class DeepCopy { public static void main(String[] args) throws CloneNotSupportedException { Teacher2 teacher = new Teacher2(); teacher.setName("riemann"); teacher.setAge(27); Student3 student1 = new Student3(); student1.setName("edgar"); student1.setAge(18); student1.setTeacher(teacher); Student3 student2 = (Student3) student1.clone(); System.out.println("拷贝后"); System.out.println(student2.getName()); System.out.println(student2.getAge()); System.out.println(student2.getTeacher().getName()); System.out.println(student2.getTeacher().getAge()); System.out.println("修改老师的信息后-------------"); // 修改老师的信息 teacher.setName("Games"); System.out.println(student1.getTeacher().getName()); System.out.println(student2.getTeacher().getName()); } } class Teacher2 implements Cloneable { private String name; private int age; public String getName() { return name; } public void setName(String name) { this.name = name; } public int getAge() { return age; } public void setAge(int age) { this.age = age; } public Object clone() throws CloneNotSupportedException { return super.clone(); } } class Student3 implements Cloneable { private String name; private int age; private Teacher2 teacher; public String getName() { return name; } public void setName(String name) { this.name = name; } public int getAge() { return age; } public void setAge(int age) { this.age = age; } public Teacher2 getTeacher() { return teacher; } public void setTeacher(Teacher2 teacher) { this.teacher = teacher; } public Object clone() throws CloneNotSupportedException { // 浅复制时： // Object object = super.clone(); // return object; // 改为深复制： Student3 student = (Student3) super.clone(); // 本来是浅复制，现在将Teacher对象复制一份并重新set进来 student.setTeacher((Teacher2) student.getTeacher().clone()); return student; } }
输出结果：
拷贝后 edgar 18 riemann 27 修改老师的信息后------------- Games riemann
结果分析：
两个引用student1和student2指向不同的两个对象，两个引用student1和student2中的两个teacher引用指向的是两个对象，但对teacher对象的修改只能影响student1对象,所以说是深拷贝。
关于Java深拷贝和浅拷贝区别，你学废了么？
