文章目录
1、静态内部类
public class Outer {
static class StaticInner{
public void show() {
System.out.println("StaticInner");
}
}
public static void main(String[] args) {
Outer.StaticInner inner = new Outer.StaticInner();
inner.show();
}
}
2、实例内部类（非静态内部类）
public class Outer {
class MemberInner{
public void show() {
System.out.println("MemberInner");
}
}
public static void main(String[] args) {
Outer outer = new Outer();
Outer.MemberInner inner = outer.new MemberInner();
inner.show();
}
}
3、静态内部类访问嵌套它的外部类的静态成员
public class Outer {
private static int sa = 5;
private int ia = 10;
static class StaticInner{
public void show() {
//静态内部类可以访问嵌套它的外部类的静态成员
System.out.println("Outer's sa = " + sa);
//Error。静态内部类不能访问嵌套它的外部类的实例成员
//System.out.println("Outer's ia = " + ia);
}
}
public static void main(String[] args) {
Outer.StaticInner inner = new Outer.StaticInner();
inner.show();
}
}
4、实例内部类访问嵌套它的外部类的成员
public class Outer {
private static int sa = 5;
private int ia = 10;
class MemberInner{
public void show() {
System.out.println("Outer's sa = " + sa);
System.out.println("Outer's ia = " + ia);
}
}
public static void main(String[] args) {
Outer outer = new Outer();
Outer.MemberInner inner = outer.new MemberInner();
inner.show();
}
}
5、内部类跟嵌套它的外部类属性重名时的访问方法
public class Outer {
private static int sa = 1;
private int ia = 2;
static class StaticInner{
private static int sa = 10;
private int ia = 20;
public void show() {
System.out.println("From StaticInner: Outer's sa = " + Outer.sa);
System.out.println("From StaticInner: StaticInner's ia = " + ia);
}
}
class MemberInner{
//Error。实例内部类中不能有非常量的静态属性
//private static int ta = 1000;
private static final int ta = 100;
private int ia = 200;
//Error。实例内部类中也不能有静态的方法
/*public static void nothing() { }*/
public void show() {
System.out.println("From MemberInner: Outer's sa = " + Outer.sa);
System.out.println("From MemberInner: Outer's ia = " + Outer.this.ia);
System.out.println("From MemberInner: MemberInner's sa = " + MemberInner.ta);
System.out.println("From MemberInner: MemberInner's ia = " + this.ia);
}
}
public static void main(String[] args) {
Outer.StaticInner si = new Outer.StaticInner();
si.show();
Outer.MemberInner mi = new Outer().new MemberInner();
mi.show();
}
}
6、方法中定义的内部类
public class Outer {
private static String staticOuterMsg = "static outer message";
private String memberOuterMsg = "member outer message";
public void show(String argMsg) {
String normalLocalMsg = "normal local message";
final String finalLocalMsg = "final local message";
class Inner{
public void print() {
System.out.println(staticOuterMsg);
System.out.println(memberOuterMsg);
System.out.println(finalLocalMsg);
//Error。方法中的内部类只能访问final局部变量
//System.out.println(normalLocalMsg);
//Error。方法中的内部类只能访问final局部变量。
//System.out.println(argMsg);
}
}
new Inner().print();
}
public static void main(String[] args) {
new Outer().show("argument message");
}
}
