import java.util.Scanner;
public class Main
{
public static void main(String[] args) throws InterruptedException
{
boolean b = false;
Scanner in=new Scanner(System.in);
System.out.println("请输入数字：520");
try{
int a=in.nextInt();
if(a==520){
System.out.println("输入正确!");
}else{
b=true;
}
}
catch (Exception e)
{
System.out.println("你输入有误，程序将在3秒后退出");
}finally{
if(b){
System.out.println("你输入有误，程序将在3秒后退出");
try{
Thread.currentThread().sleep(3000);
}catch(InterruptedException e){
}
finally{
System.exit(0);
}
}
}
}
}
/*我写了，貌似还是没有退出啊*/

好了，有用啊，刚才写错b的值了

/*我改写了一下，也有用啊*/
import java.util.Scanner;
public class Main
{
public static void main(String[] args) throws InterruptedException
{
Scanner in=new Scanner(System.in);
System.out.println("请输入数字：520");
try{
int a=in.nextInt();
if(a==520){
System.out.println("输入正确!");
}
}
catch (Exception e)
{
System.out.println("你输入有误，程序将在3秒后退出");
Thread.currentThread().sleep(3000);
}
finally{
System.exit(0);
}
}
}

/*我在修改了一下，最终结果是这样的*/
import java.util.Scanner;
public class Main
{
public static void main(String[] args) throws InterruptedException
{
Scanner in=new Scanner(System.in);
System.out.println("请输入数字：520");
try{
int a=in.nextInt();
if(a==520){
System.out.println("输入正确!");
}else{
System.out.println("你输错了，程序将在3秒后退出");
Thread.currentThread().sleep(3000);
System.exit(0);
}
}
catch (Exception e)
{
System.out.println("你输入有误，程序将在3秒后退出");
Thread.currentThread().sleep(3000);
System.exit(0);
}
}
}