设计模式学习—传输对象模式(Transfer Object Design Pattern)

﹏ヽ暗。殇╰゛Y 2022-06-08 00:25 100阅读 0赞

# 一、我的理解 #

该模式是作为网络中一种传输数据的方式，它利用简单的POJO对象作为传输对象，相当于一种网络传输格式的约定。

# 二、实现方式 #

业务对象负责处理数据，它只接收简单的POJO对象，然后调用其getter/setter方法获取和修改数据。

# 三、实例 #

![Center][]

###### Java实例 ######

StudentVO类：数据对象，POJO类，只有简单的getter/setter方法

package com.study.dp.transferobject;
    
    public class StudentVO {
    
        private String name;
        private int rollNo;
        
        public StudentVO(String name, int rollNo) {
            this.name = name;
            this.rollNo = rollNo;
        }
    
        public String getName() {
            return name;
        }
    
        public void setName(String name) {
            this.name = name;
        }
    
        public int getRollNo() {
            return rollNo;
        }
    
        public void setRollNo(int rollNo) {
            this.rollNo = rollNo;
        }
        
    }

StudentBO类：业务对象，它负责处理相应数据

package com.study.dp.transferobject;
    
    import java.util.ArrayList;
    import java.util.List;
    
    public class StudentBO {
    
        // 列表是当做一个数据库
        List<StudentVO> students;
        
        public StudentBO() {
            students = new ArrayList<>();
            StudentVO student1 = new StudentVO("Robert", 0);
            StudentVO student2 = new StudentVO("John", 1);
            students.add(student1);
            students.add(student2);
        }
        
        public void deleteStudent(StudentVO student) {
            students.remove(student.getRollNo());
            System.out.println("Student: Roll No "+student.getRollNo()+", deleted from database");
        }
        
        // 从数据库中检索出学生名单
        public List<StudentVO> getAllStudents(){
            return students;
        }
        
        public StudentVO getStudent(int rollNo) {
            return students.get(rollNo);
        }
        
        public void updateStudent(StudentVO student) {
            students.get(student.getRollNo()).setName(student.getName());
            System.out.println("Student: Roll No "+student.getRollNo()+", updated in the database");
        }
        
    }

Demo类：测试类

package com.study.dp.transferobject;
    
    public class Demo {
    
        public static void main(String[] args) {
            StudentBO studentBusinessObject = new StudentBO();
            
            // 输出所有学生
            for(StudentVO student:studentBusinessObject.getAllStudents()) {
                System.out.println("Student: [RollNo: "+student.getRollNo()+", Name: "+student.getName()+"]");
            }
            
            // 更新学生
            StudentVO student = studentBusinessObject.getAllStudents().get(0);
            student.setName("Michael");
            studentBusinessObject.updateStudent(student);
            
            // 获取学生
            studentBusinessObject.getStudent(0);
            System.out.println("Student: [RollNo: "+student.getRollNo()+", Name: "+student.getName()+"]");
        }
        
    }

# 四、应用场景 #

[Center]: /images/20220608/00e3091e643b4919ad4914ce74536015.png