在java中有四种类型的内部类，下面给出它们的名字和相应的实例
1. 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();
}
}
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Inner class reference is: Outer$Inner@19e7ce87
2. Member Inner Class
成员类是具体实例，可以访问所有的方法、域、和外部类的引用.
public class Outer {
private int x = 100;
public void makeInner(){
Inner in = new Inner();
in.seeOuter();
}
class Inner{
public void seeOuter(){
System.out.println("Outer x is " + x);
System.out.println("Inner class reference is " + this);
System.out.println("Outer class reference is " + Outer.this);
}
}
public static void main(String [] args){
Outer o = new Outer();
Inner i = o.new Inner();
i.seeOuter();
}
}
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Outer x is 100
Inner class reference is Outer$Inner@4dfd9726
Outer class reference is Outer@43ce67ca
3. 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();
}
}
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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();
}
}
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x is static outer
4. Anonymous Inner Classes（匿名内部类）
这种内部类经常用在当你想给GUI应用的小组件增加事件监听的时候使用
button.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
comp.setText("Button has been clicked");
}
});
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