java 内部类和闭包
Posted
tags:
篇首语：本文由小常识网(cha138.com)小编为大家整理，主要介绍了java 内部类和闭包相关的知识，希望对你有一定的参考价值。
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!");
}
}
以上是关于java 内部类和闭包的主要内容，如果未能解决你的问题，请参考以下文章