在Java中有4种不同类型的内部类可以使用。下面给出它们的名称和例子。
1.静态嵌套类(Static Nested Classes)
| class Outer { static class Inner { void go() { System.out.println("Inner class reference is: " + this); } }} public class Test { public static void main(String[] args) { Outer.Inner n = new Outer.Inner(); n.go(); }} |
输出：Inner class reference is: Outer$Inner@19e7ce87
2.成员内部类(Member Inner Class)
成员类是特定于实例的。它可以访问所有方法，字段和外部类本身的引用。
| public class Outer { private int x = 100; public void makeInner(){ Inner in = new Inner(); in.seeOuter(); } class Inner{ public void seeOuter(){ System.out.println("Outer x is " + x); System.out.println("Inner class reference is " + this); System.out.println("Outer class reference is " + Outer.this); } } public static void main(String [] args){ Outer o = new Outer(); Inner i = o.new Inner(); i.seeOuter(); }} |
输出：
Outer x is 100 Inner class reference is Outer$Inner@4dfd9726 Outer class reference is Outer@43ce67ca |
3.局部方法内部类(Method-Local Inner Classes)
| public class Outer { private String x = "outer"; public void doStuff() { class MyInner { public void seeOuter() { System.out.println("x is " + x); } } MyInner i = new MyInner(); i.seeOuter(); } public static void main(String[] args) { Outer o = new Outer(); o.doStuff(); }} |
输出：x is outer
| public class Outer { private static String x = "static outer"; public static void doStuff() { class MyInner { public void seeOuter() { System.out.println("x is " + x); } } MyInner i = new MyInner(); i.seeOuter(); } public static void main(String[] args) { Outer.doStuff(); }} |
输出：x is static outer
4.匿名内部类(Anonymous Inner Classes)
当您需要给一个GUI应用程序窗口小部件加一个动作监听器时，匿名内部类就会经常被用到。
| button.addActionListener(new ActionListener(){ public void actionPerformed(ActionEvent e){ comp.setText("Button has been clicked"); }}); |
本文内容不用于商业目的，如涉及知识产权问题，请权利人联系51Testing小编(021-64471599-8017)，我们将立即处理。
