Java 内部类和闭包

内部类（inner class）

public class Outer{    private String name;    class Inner{        public String getOuterName(){            return Outer.this.name;        }        public void setOuterName(String name){            Outer.this.name = name;        }    }    public static void main(String[] args){        Outer outer = new Outer();        Outer.Inner inner = outer.new Inner();        inner.setOuterName("wangtengfei");        System.out.println(inner.getOuterName());    }}

局部内部类

public class Outer{    private String name;    private String sexual = "male";    class Inner1{        public String getOuterName(){            return Outer.this.name;        }        public void setOuterName(String name){            Outer.this.name = name;        }    }    public void updateName(final String name,final String sexual){        class Inner2{             public void changeOuterInfo(){                Outer.this.name = name;                Outer.this.sexual = sexual;            }        }        Inner2 inner2 = new Inner2();        inner2.changeOuterInfo();    }    public String getSexual(){        return sexual;    }    public static void main(String[] args){        Outer outer = new Outer();        Outer.Inner1 inner = outer.new Inner1();        inner.setOuterName("wangtengfei");        System.out.println("Name:"+inner.getOuterName()+",sexual:"+outer.getSexual());        outer.updateName("Iris","female");        System.out.println("Name:"+inner.getOuterName()+",sexual:"+outer.getSexual());    }}

静态内部类

public class Outer{    private String name;    private String sexual = "male";    public static int count;    public Outer(){        count++;    }    class Inner1{        public String getOuterName(){            return Outer.this.name;        }        public void setOuterName(String name){            Outer.this.name = name;        }    }    public void updateName(final String name,final String sexual){        class Inner2{             public void changeOuterInfo(){                Outer.this.name = name;                Outer.this.sexual = sexual;            }        }        Inner2 inner2 = new Inner2();        inner2.changeOuterInfo();    }    public String getSexual(){        return sexual;    }    public static class Inner3{        public String getOuterInstanceCount(){            return "there are "+Outer.count+" Outer instances have been created";        }    }    public static void main(String[] args){        Outer outer = new Outer();        Outer.Inner1 inner = outer.new Inner1();        inner.setOuterName("wangtengfei");        System.out.println("Name:"+inner.getOuterName()+",sexual:"+outer.getSexual());        outer.updateName("Iris","female");        System.out.println("Name:"+inner.getOuterName()+",sexual:"+outer.getSexual());        Inner3 inner3 = new Inner3();        System.out.println(inner3.getOuterInstanceCount());    }}

匿名内部类

public class Outer{    private String name;    private String sexual = "male";    public static int count;    public Outer(){        count++;    }    class Inner1{        public String getOuterName(){            return Outer.this.name;        }        public void setOuterName(String name){            Outer.this.name = name;        }    }    public void updateName(final String name,final String sexual){        class Inner2{             public void changeOuterInfo(){                Outer.this.name = name;                Outer.this.sexual = sexual;            }        }        Inner2 inner2 = new Inner2();        inner2.changeOuterInfo();    }    public String getSexual(){        return sexual;    }    public static class Inner3{        public String getOuterInstanceCount(){            return "there are "+Outer.count+" Outer instances have been created";        }    }    public void showTime(){        Thread t = new Thread(new Runnable() {            public void run() {                int time = 60;                int i = 0;                while(i< time){                    System.out.println(Thread.currentThread().toString());                    System.out.println((new Date(System.currentTimeMillis())).toString());                    i+=5;                    try {                        Thread.sleep(5*1000);                    } catch (InterruptedException e) {                        e.printStackTrace();                    }                }            }        });        ExecutorService executorService = Executors.newCachedThreadPool();        executorService.execute(t);        executorService.execute(t);    }    public static void main(String[] args){        Outer outer = new Outer();        Outer.Inner1 inner = outer.new Inner1();        inner.setOuterName("wangtengfei");        System.out.println("Name:"+inner.getOuterName()+",sexual:"+outer.getSexual());        outer.updateName("Iris","female");        System.out.println("Name:"+inner.getOuterName()+",sexual:"+outer.getSexual());        Inner3 inner3 = new Inner3();        System.out.println(inner3.getOuterInstanceCount());        outer.showTime();        System.out.println("main process end!");    }}

回调(callbacks)和闭包(closure)

函数式编程中常见的概念，内部作用域中调用定义它的外部作用域中的成员或者方法。
示例，在局部内部类Inner2的changeOuterInfo()方法中调用外部Outer类的showTime()方法,注意调用方式(Outer.this.showTime())

public class Outer{    private String name;    private String sexual = "male";    public static int count;    public Outer(){        count++;    }    class Inner1{        public String getOuterName(){            return Outer.this.name;        }        public void setOuterName(String name){            Outer.this.name = name;        }    }    public void updateName(final String name,final String sexual){        class Inner2{             public void changeOuterInfo(){                Outer.this.name = name;                Outer.this.sexual = sexual;                Outer.this.showTime();            }        }        Inner2 inner2 = new Inner2();        inner2.changeOuterInfo();    }    public String getSexual(){        return sexual;    }    public static class Inner3{        public String getOuterInstanceCount(){            return "there are "+Outer.count+" Outer instances have been created";        }    }    public void showTime(){        Thread t = new Thread(new Runnable() {            public void run() {                int time = 60;                int i = 0;                while(i< time){                    System.out.println(Thread.currentThread().toString());                    System.out.println((new Date(System.currentTimeMillis())).toString());                    i+=5;                    try {                        Thread.sleep(5*1000);                    } catch (InterruptedException e) {                        e.printStackTrace();                    }                }            }        });        ExecutorService executorService = Executors.newCachedThreadPool();        executorService.execute(t);        executorService.execute(t);    }    public static void main(String[] args){        Outer outer = new Outer();        Outer.Inner1 inner = outer.new Inner1();        inner.setOuterName("wangtengfei");        System.out.println("Name:"+inner.getOuterName()+",sexual:"+outer.getSexual());        outer.updateName("Iris","female");        System.out.println("Name:"+inner.getOuterName()+",sexual:"+outer.getSexual());        Inner3 inner3 = new Inner3();        System.out.println(inner3.getOuterInstanceCount());//        outer.showTime();        System.out.println("main process end!");    }}