SOLID原则在Java中的实践解析

class User {
    private String name;
public void setName(String name) {
    this.name = name;
}

public void saveToFile() {
    // 保存用户到文件
}
}

interface Shape {
    double area();
}
class Rectangle implements Shape {
double width, height;
public double area() { return width * height; }
}
class Circle implements Shape {
double radius;
public double area() { return Math.PI  radius  radius; }
}
class AreaCalculator {
public double totalArea(List shapes) {
return shapes.stream().mapToDouble(Shape::area).sum();
}
}

interface Flyable {
    void fly();
}
class Sparrow implements Flyable {
public void fly() { System.out.println("麻雀飞行"); }
}
class Penguin { // 不实现Flyable
public void swim() { System.out.println("企鹅游泳"); }
}

interface Workable {
    void work();
}
interface Eatable {
void eat();
}
class HumanWorker implements Workable, Eatable {
public void work() { / 工作 / }
public void eat() { / 吃饭 / }
}
class RobotWorker implements Workable {
public void work() { / 工作 / }
// 不实现eat，避免无效方法
}

interface Database {
    void connect();
    void save(String data);
}
class MySQLDatabase implements Database {
public void connect() { / 连接MySQL / }
public void save(String data) { / 保存到MySQL / }
}
class UserService {
private Database db;
public UserService(Database db) {
    this.db = db;
}

public void saveUser(String user) {
    db.save(user);
}
}