问题描述

哪位大神帮忙解决一下Keyboard cannot be resolved的问题

具体代码如下
package Students;
import java.sql.*;
import java.util.ArrayList;
public class Test
{
private String id;
private String name;
private int math;
private int english;
private int java;
private int computer;

   public String getId()
   {
          return id;
   }

   public void setId(String id)
   {
          this.id = id;
   }

   public String getName()
   {
          return name;
   }

   public void setName(String name)
   {
          this.name = name;
   }

   public int getMath()
   {
          return math;
   }

   public void setMath(int math)
   {
          this.math = math;
   }

   public int getEnglish()
   {
          return english;
   }

   public void setEnglish(int english)
   {
          this.english = english;
   }

   public int getJava()
   {
          return java;
   }

   public void setJava(int java)
   {
          this.java = java;
   }

   public int getComputer()
   {
          return computer;
   }

   public void setComputer(int computer)
   {
          this.computer = computer;
   }

   public static void main(String[] args) throws Exception
   {
          String id;
          String cid;
          String name;
          int math;
          int english;
          int java;
          int computer;
          String DBDriver = "sun.jdbc.odbc.JdbcOdbcDriver";
          String conStr = "jdbc:odbc:student";
          Connection con = null;
          Statement stmt = null;
          ResultSet rs = null;
          Class.forName(DBDriver);
          con = DriverManager.getConnection(conStr, "student", "123");
          stmt = con.createStatement();
          String s = "nnttt学 生 成 绩nntt 1 新 增ntt 2 更 改ntt 3 删 除ntt 4 查 找ntt 5 显 示ntt 0 退 出nn";
          System.out.print(s);
          int choice = Keyboard.getInteger();
          switch (choice)
          {

                 // 添加学生
                 case 1:
                        System.out.print("请输入学生信息n");
                        System.out.print("学号:");
                        id = Keyboard.getString();
                        System.out.print("姓名:");
                        name = Keyboard.getString();
                        System.out.print("数学:");
                        math = Keyboard.getInteger();
                        System.out.print("英语:");
                        english = Keyboard.getInteger();
                        System.out.print("JAVA:");
                        java = Keyboard.getInteger();
                        System.out.print("计算机:");
                        computer = Keyboard.getInteger();
                        stmt.executeUpdate("insert into lxh1 values('" + id + "','"
                                      + name + "','" + math + "','" + english + "','" + java
                                      + "','" + computer + "')");
                        System.out.println("n添加完成。");
                        break;

                 // 更改成绩
                 case 2:

                               System.out.println("请输入要改的学生学号：");
                               cid = Keyboard.getString();
                               System.out.println("数学：");
                               math = Keyboard.getInteger();
                               System.out.println("英语：");
                               english = Keyboard.getInteger();
                               System.out.println("JAVA：");
                               java = Keyboard.getInteger();
                               System.out.println("计算机：");
                               computer = Keyboard.getInteger();
                               stmt.executeUpdate("update lxh1 set math='" + math + "',english='"
                                             + english + "',java='" + java + "',computer='" + computer
                                             + "' where sno=" + cid + "");
                               System.out.println("n修改完成");
                               break;

                 // 删除指定学生
                 case 3:
                        System.out.println("请输入要改的学生学号：");
                        cid = Keyboard.getString();
                        stmt.executeUpdate("delete from lxh1 where sno=" + cid + "");
                        System.out.println("n删除完成");
                        break;

                 // 显示指定学生
                 case 4:
                        System.out.println("请输入查找的学生学号：");
                        cid = Keyboard.getString();
                        System.out.println("n" + cid
                                      + "号学生信息nn学号t姓名t数学t英语tJAVAt计算机t");
                        rs = stmt.executeQuery("select * from lxh1 where sno=" + cid
                                      + "");
                        while (rs.next())
                        {
                               System.out.println(rs.getInt("sno") + "t"
                                             + rs.getString("sname") + "t" + rs.getString("math")
                                             + "t" + rs.getString("english") + "t"
                                             + rs.getString("java") + "t"
                                             + rs.getString("computer") + "t");
                        }

                        break;

                 case 5:
                        // 输出全部信息
                        System.out.println("n全部学生信息nn学号t姓名t数学t英语tJAVAt计算机t平均成绩");
                        rs = stmt.executeQuery("select * from lxh1 order by math desc");
                        while (rs.next())
                        {
                               int a = rs.getInt("math");
                               int b = rs.getInt("english");
                               int c = rs.getInt("java");
                               int d = rs.getInt("computer");
                               System.out.println(rs.getString("sno") + "t"
                                             + rs.getString("sname") + "t" + a + "t" + b + "t"
                                             + c + "t" + d + "t" + ((a + b + c + d) / 4));
                        }
                        ;

                        // 输出平均分
                        System.out.println("n各科平均分nn数学t英语tJAVAt计算机t");
                        rs = stmt
                                      .executeQuery("select avg(math),avg(english),avg(java),avg(computer) from lxh1");
                        while (rs.next())
                        {
                               System.out.println(rs.getInt(1) + "t" + rs.getInt(2) + "t"
                                             + rs.getInt(3) + "t" + rs.getInt(4));
                        }
                        ;

                        // 输出最高分
                        System.out.println("n各科最高分nn数学t英语tJAVAt计算机t");
                        rs = stmt.executeQuery("select max(math),max(english),max(java),max(computer) from lxh1");
                        while (rs.next())
                        {
                               System.out.println(rs.getInt(1) + "t" + rs.getInt(2) + "t"
                                             + rs.getInt(3) + "t" + rs.getInt(4));
                        }
                        ;

                        // 输出最低分
                        System.out.println("n各科最低分nn数学t英语tJAVAt计算机t");
                        rs = stmt
                                      .executeQuery("select min(math),min(english),min(java),min(computer) from lxh1");
                        while (rs.next())
                        {
                               System.out.println(rs.getInt(1) + "t" + rs.getInt(2) + "t"
                                             + rs.getInt(3) + "t" + rs.getInt(4));
                        }
                        ;
                        break;

                 case 0:
                        break;

                 default:
                        System.out.println("感谢您的使用,再见!");
          }
          ;
          stmt.close();
          con.close();
   }

}

解决方案

需要导入java.io

import java.io.*;

http://www.cnblogs.com/xuxm2007/archive/2011/10/20/2219104.html

解决方案二：

应该是引入的Jar包不全引起的