1.动态绑定
*在程序运行过程中,根据具体的实例对象才能具体确定是哪个方法
Father ft=new Son(); ft.say(); Son继承自Father,重写了say()
2.静态变量
在变量前家static关键字
public class SyncThread implements Runnable {
private static int count;
@Override
public void run() {
synchronized(this) {
for (int i = 0; i < 5; i++) {
try {
System.out.println(Thread.currentThread().getName() + ":" + (count++));
Thread.sleep(100);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}
public static void main(String[] args) {
SyncThread s1 = new SyncThread();
SyncThread s2 = new SyncThread();
Thread t1 = new Thread(s1);
Thread t2 = new Thread(s2);
t1.start();
t2.start();
}
}
3.静态方法
在方法前面加上static关键字,引用静态方法时,可以用类名.方法名或者对象名.方法名的形式
public class TestStatic {
public static void main(String[]args){
System.out.println(S.getStatic()); //类名加前缀访问静态方法
S s=new S();
System.out.println(s.getStatic()); //使用实例化对象名访问静态方法
System.out.println(s.get());
}
public static class S
{
private static int a;
private int t=0;
static{
a=10;
}
public static int getStatic()
{
return a;
public int getT()
{
return t;
}
public int get()
{
getT();
getStatic();
t=a;
return t;
}
}
}
4.静态代码块
static代码块也叫静态代码块,可以有多个
public class StaticBlockDemo {
static{
System.out.println("静态代码块");
}
public StaticBlockDemo(){
System.out.println("构造方法");
}
public static void main(String[] args) {
StaticBlockDemo d = new StaticBlockDemo();
StaticBlockDemo d2 = new StaticBlockDemo();
}
}
静态代码块优先于构造方法执行,且在加载时只执行一次
5.明天学习内容:Static关键字,Final关键字,Abstract关键字
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原文:https://www.cnblogs.com/SirNie/p/13434598.html