import java.util.Scanner;

public class Year{
    public static void main(String[] args) {
        int year;
        Scanner scan = new Scanner(System.in);
        System.out.println("请输入年份：");        
        year = scan.nextInt();
        /*if (year < 0 || year > 3000) {
            System.out.println("输入有误，请重新输入：");
            year = scan.nextInt();
        }*/
        testYear(year);
        if((year % 4 == 0) && (year % 100 != 0) || (year % 400 == 0)) {
            System.out.println(year + "是闰年！");
        }
        else {
            System.out.println(year + "不是闰年！");
        }
    }

    static int testYear() {            //此处要用static
        Scanner scan = new Scanner(System.in);
        if(scan.hasnextInt())
            return scan.nextInt();
        else {
            System.out.println("输入有误，请重新输入：");
            return testYear();
        }
    }
}

    public static void main(String[] args) {
        int year;
        boolean flag = true;
        
        System.out.println("==========请输入年份============");
        
        while(flag){
            
            try{
                Scanner scanner = new Scanner(System.in);
                year = scanner.nextInt();
                if(year > 0 && year <3000){
                    if(year % 4 == 0 && year % 100 != 0 || year % 400 == 0){
                        System.out.println(year+"是闰年");
                    }else{
                        System.out.println(year + "是平年 ");
                    }
                    flag = false;
                }else{
                    System.out.println("输入的数字不在0-3000范围，请重新输入");
                }
            }catch(Exception e){
                System.out.println("========输入的年份不是整数，请重新输入===========");
            }
            
        }
    }

------解决方案--------------------
只是给你重写一下那个函数：
static int testYear() { 
        Scanner scan = new Scanner(System.in);
        int year = 0;
        while(true){
        try{
           year = scan.nextInt();
           if(year>1 && year<3000)
               break;
           System.out.println("输入的数字不再1到3000之间，重新输入");
        }catch{
           System.out.println("输入的不是数字，重新输入")；
        }
       
        }
    }

------解决方案--------------------
来个
while(true){
  if(year<0|year>3000){
  System.out.print("重新输入");
 continue;
}
......
}