java小程序老是提示出错

import java.util.*;
public class Test {

public static void main(String[] args) {                          //此行有错！
   int score;
   Scanner scanner=new Scanner(System.in);

   System.out.println("请问您的成绩是多少？（0-100）");
   score=scanner.nextInt();

   if ((score>100) || (score<0))
       System.out.println("输入错误！");
       else if(score>=90)
           System.out.println("您的成绩是优");
           else if(score>=80)
               System.out.println("您的成绩是良！");
           else if(score>=60)
               System.out.println("您的成绩是及格！");
           else
               System.out.println("您的成绩是不及格，必须补考！");


}

}

错误：
Exception in thread "main" java.lang.Error: Unresolved compilation problems:
String cannot be resolved to a type
Scanner cannot be resolved to a type
Scanner cannot be resolved to a type
System cannot be resolved to a variable
System cannot be resolved
System cannot be resolved
System cannot be resolved
System cannot be resolved
System cannot be resolved
System cannot be resolved

at Test.main(Test.java:4)

程序没问题，Unresolved compilation problems。应该是编译环境有问题。你百度下

在我的电脑上跑了你的程序，完全没问题，可能确实是环境的问题

你用到的Scanner,String,等这些类没导包，或者是你不小心吧原来这些类对应的jar包移动了位置，看看你的classpath环境变量的值再去对应的路径下看看有没有这些类对应的包

类似的错误哎。http://blog.csdn.net/chl033/article/details/4744601

代码没有问题，你检查一下编译环境吧，JDK

代码没问题。编译环境的JDK的问题。