java中如何给内部类的属性赋值

在 Java 中，内部类的属性赋值方式取决于该属性的访问修饰符、内部类的类型（非静态或静态），以及赋值的时机。以下是几种常见的方式：

1. 通过构造方法赋值

class Outer {class Inner {private String name;// 构造方法赋值public Inner(String name) {this.name = name;}public void print() {System.out.println("Name: " + name);}}public static void main(String[] args) {Outer outer = new Outer();Inner inner = outer.new Inner("张三");inner.print(); // 输出：Name: 张三}
}

2. 通过 setter 方法赋值

class Outer {class Inner {private int age;public void setAge(int age) {this.age = age;}public void print() {System.out.println("Age: " + age);}}public static void main(String[] args) {Outer outer = new Outer();Inner inner = outer.new Inner();inner.setAge(25);inner.print(); // 输出：Age: 25}
}

3. 直接访问（前提是属性是 public）

class Outer {class Inner {public String message;}public static void main(String[] args) {Outer outer = new Outer();Inner inner = outer.new Inner();inner.message = "Hello, world!";System.out.println(inner.message); // 输出：Hello, world!}
}

4. 赋值给静态内部类的属性

class Outer {static class Inner {private int number;public void setNumber(int number) {this.number = number;}public void print() {System.out.println("Number: " + number);}}public static void main(String[] args) {Inner inner = new Inner();inner.setNumber(100);inner.print(); // 输出：Number: 100}
}