原型模式

模式定义

指原型实例指定创建对象的种类，并且通过拷贝这些原型创建对象新的对象

clone 方法

（直接clone 可能导致引用类型的属性指向原来的地址）除非子类里面的引用类型也实现cloneable，clone方法里面在将子类clone后覆盖原本的引用

class ProtoProduct implements Cloneable{
    private String part1;
    private String part2;
    private String part3;
    private String part4;
    public ProtoProduct(String part1, String part2, String part3, String part4) {
        this.part1 = part1;
        this.part2 = part2;
        this.part3 = part3;
        this.part4 = part4;
    }
    @Override
    protected ProtoProduct clone() throws CloneNotSupportedException {
        return (ProtoProduct)super.clone();
    }
    public String getPart1() {
        return part1;
    }
    public void setPart1(String part1) {
        this.part1 = part1;
    }
    public String getPart2() {
        return part2;
    }
    public void setPart2(String part2) {
        this.part2 = part2;
    }
    public String getPart3() {
        return part3;
    }
    public void setPart3(String part3) {
        this.part3 = part3;
    }
    public String getPart4() {
        return part4;
    }
    public void setPart4(String part4) {
        this.part4 = part4;
    }
}

深拷贝方式

构造函数

重载clone()方法

apache common lang 序列化

gson序列化

 Address address = new Address("杭州", "中国");
    User user = new User("大山", address);
    // 使用Gson序列化进行深拷贝
    Gson gson = new Gson();
    User copyUser = gson.fromJson(gson.toJson(user), User.class);
    // 修改源对象的值
    user.getAddress().setCity("深圳");
    // 检查两个对象的值不同
    assertNotSame(user.getAddress().getCity(), copyUser.getAddress().getCity());

jackson序列化

 Address address = new Address("杭州", "中国");
    User user = new User("大山", address);
    // 使用Jackson序列化进行深拷贝
    ObjectMapper objectMapper = new ObjectMapper();
    User copyUser = objectMapper.readValue(objectMapper.writeValueAsString(user), User.class);
    // 修改源对象的值
    user.getAddress().setCity("深圳");
    // 检查两个对象的值不同
    assertNotSame(user.getAddress().getCity(), copyUser.getAddress().getCity());