Java 世界中的类、包、模块、组件、容器、服务、平台

Java 是一种广泛使用的编程语言，它采用面向对象的编程范式，拥有丰富的类库和强大的生态系统。在 Java 的世界中，有许多重要的概念和组件，如类、包、模块、组件、容器、服务和平台。本文将对这些概念进行介绍，并通过案例代码来加深理解。

java
public class Person {
    private String name;
    private int age;
    public Person(String name, int age) {
        this.name = name;
        this.age = age;
    }
    public void sayHello() {
        System.out.println("Hello, my name is " + name + " and I am " + age + " years old.");
    }
}

java
package com.example;
public class Main {
    public static void main(String[] args) {
        Person person = new Person("John", 25);
        person.sayHello();
    }
}

java
module com.example.module {
    requires com.example;
    exports com.example.module;
}

java
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
@Component
public class MyComponent {
    @Autowired
    private MyService myService;
    public void doSomething() {
        myService.doSomething();
    }
}

java
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class Main {
    public static void main(String[] args) {
        ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
        MyComponent myComponent = context.getBean(MyComponent.class);
        myComponent.doSomething();
    }
}

java
public interface MyService {
    void doSomething();
}

java
public class Main {
    public static void main(String[] args) {
        System.out.println("Hello, world!");
    }
}