Java---设计模块(值对象)

★ 场景和问题
在Java开发时，需要来回交换大量的数据，比如要为方法传入参数，也要获取方法的返回值，该如何能更好的进行数据的交互？

★ 基本的编写步骤
◎第1步：写一个类，实现可序列化（如果以后数据是往数据库里存的，那么可以不序列化，节省资源）
◎第2步：私有化所有属性，保持一个默认构造方法(public无参)
◎第3步：为每个属性提供get()、set()方法（如果是boolean型变量，最好把get改成is）
◎第4步：推荐覆盖实现equals()、hashCode()和toString()方法

值对象的本质是“封装数据”
User 类：

package cn.hncu.pattern.factory.vo.v2.vo;import java.io.Serializable;public class User implements Serializable{    //只能将支持 java.io.Serializable 接口的对象写入流中,必须实现这个接口    private String userId;    private String tel;    private String address;    private int age;    private boolean isMale;    public User() {    }    public User(String userId, String tel, String address, int age){        this.userId = userId;        this.tel = tel;        this.address = address;        this.age = age;    }    public String getTel() {        return tel;    }    public void setTel(String tel) {        this.tel = tel;    }    public String getAddress() {        return address;    }    public void setAddress(String address) {        this.address = address;    }    public int getAge() {        return age;    }    public void setAge(int age) {        this.age = age;    }    public String getUserId() {        return userId;    }    public void setUserId(String userId) {        this.userId = userId;    }    public boolean isMale() {        return isMale;    }    public void setMale(boolean isMale) {        this.isMale = isMale;    }    @Override    public int hashCode() {        final int prime = 31;        int result = 1;        result = prime * result + ((userId == null) ? 0 : userId.hashCode());        return result;    }    @Override    public boolean equals(Object obj) {        if (this == obj)            return true;        if (obj == null)            return false;        if (getClass() != obj.getClass())            return false;        User other = (User) obj;        if (userId == null) {            if (other.userId != null)                return false;        } else if (!userId.equals(other.userId))            return false;        return true;    }    @Override    public String toString() {        return "User [userId=" + userId + ", tel=" + tel + ", address="                + address + ", age=" + age + "]";    }}

B类：

package cn.hncu.pattern.factory.vo.v2;import cn.hncu.pattern.factory.vo.v2.vo.User;public class B {    String userId=null;    User user = null;    public boolean sendData(User user){ //Value Object ----Model        System.out.println("数据已经接受到。。。");        operate(user);        return true;    }    private void operate(User user) {        this.user = user;        this.user.setUserId("CN_"+user.getUserId());        System.out.println("处理数据...");    }    public User getData(){        return user;    }    public String getUserId(){        return userId;    }}

A类：

package cn.hncu.pattern.factory.vo.v2;import cn.hncu.pattern.factory.vo.v2.vo.User;public class A {    public static void main(String[] args) {        B obj = new B();        User user = new User("A001", "13512345678", "hncu",20);        obj.sendData(user);        User data = obj.getData();        System.out.println( data.getUserId() );        System.out.println(data);        User user2 = new User();        user2.setAge(21);        user2.setUserId("A002");        System.out.println(user2);        obj.sendData(user2);        System.out.println(user2);        //可以做得更好的：         // Id可以用唱票模型 2318,2319,......    }}

输出:

数据已经接受到。。。处理数据...CN_A001User [userId=CN_A001, tel=13512345678, address=hncu, age=20]User [userId=A002, tel=null, address=null, age=21]数据已经接受到。。。处理数据...User [userId=CN_A002, tel=null, address=null, age=21]