目錄

design pattern 以java 為例

單一責任原則（Single Responsibility Principle, SRP）

描述

一個class應該只負責一件事

範例

我們現在要做員工的報表，所以可以將員工跟報表拆分成不同class，如果員工內容有變，輸出報表則不用變

Employee

class Employee {
    private String id;
    private String name;
    private String department;

    // Constructor, getters, and setters
    public Employee(String id, String name, String department) {
        this.id = id;
        this.name = name;
        this.department = department;
    }

    // Employee related methods
    public String getId() { return id; }
    public String getName() { return name; }
    public String getDepartment() { return department; }
}

EmployeeReportFormatter

class EmployeeReportFormatter {
    public String formatToCSV(Employee employee) {
        return String.format("%s,%s,%s\n", employee.getId(), employee.getName(), employee.getDepartment());
    }
    
    public String formatToXML(Employee employee) {
        return String.format("<employee><id>%s</id><name>%s</name><department>%s</department></employee>", 
                             employee.getId(), employee.getName(), employee.getDepartment());
    }
}

實作

public class SRPDemo {
    public static void main(String[] args) {
        Employee emp = new Employee("1", "John Doe", "Engineering");
        EmployeeReportFormatter formatter = new EmployeeReportFormatter();
        
        System.out.println("CSV Format:");
        System.out.println(formatter.formatToCSV(emp));
        
        System.out.println("XML Format:");
        System.out.println(formatter.formatToXML(emp));
    }
}

• output

  CSV Format:
  1,John Doe,Engineering
  
  XML Format:
  <employee><id>1</id><name>John Doe</name><department>Engineering</department></employee>