教大家使用java实现顶一下踩一下功能

package com.test; 
 
import java.io.IOException; 
import java.io.PrintWriter; 
import java.sql.Connection; 
import java.sql.DriverManager; 
import java.sql.ResultSet; 
import java.sql.SQLException; 
import java.sql.Statement; 
import java.text.NumberFormat; 
 
import javax.servlet.ServletException; 
import javax.servlet.http.HttpServlet; 
import javax.servlet.http.HttpServletRequest; 
import javax.servlet.http.HttpServletResponse; 
 
public class Digg extends HttpServlet { 
  private static Connection con = null; 
  private static Statement stmt = null; 
 
  /** 
   * Constructor of the object. 
   */ 
  public Digg() { 
    super(); 
  } 
 
  /** 
   * Destruction of the servlet. 
 
   */ 
  public void destroy() { 
    super.destroy(); // Just puts "destroy" string in log 
    // Put your code here 
  } 
 
 
  public void doGet(HttpServletRequest request, HttpServletResponse response) 
      throws ServletException, IOException { 
 
    this.doPost(request, response); 
  } 
 
  public void doPost(HttpServletRequest request, HttpServletResponse response) 
      throws ServletException, IOException { 
    request.setCharacterEncoding("utf8"); 
    response.setCharacterEncoding("utf8"); 
    String action = request.getParameter("action"); 
    String digtype = request.getParameter("digtype"); 
    if(action.equals("digs")){ 
      try { 
        response.getWriter().write(dig(digtype)); 
         
      } catch (Exception e) { 
        e.printStackTrace(); 
      } 
    }else if(action.equals("getdigshtml")){ 
      try { 
        response.getWriter().write(getDigHtml()); 
      } catch (Exception e) { 
        e.printStackTrace(); 
      } 
    } 
  } 
  private String dig(String digtype)throws Exception{ 
    String sql =""; 
    if(digtype.equals("digs")){ 
      sql ="update dig set digs=digs+1 where id =1"; 
    }else{ 
      sql ="update dig set undigs=undigs+1 where id =1"; 
    } 
    int num =stmt.executeUpdate(sql); 
    if(num>0){ 
      return "3"; 
    } 
    return "1"; 
  } 
  public static void main(String[] args){  
    NumberFormat nf = NumberFormat.getPercentInstance();  
    nf.setMaximumIntegerDigits(4);  
    nf.setMaximumFractionDigits(6);  
    double d = (double)1/(double)7;  
    System.out.println(nf.format(d));  
    }  
  private String getDigHtml()throws Exception{ 
    NumberFormat nf = NumberFormat.getPercentInstance();  
    nf.setMaximumIntegerDigits(3);  
    nf.setMaximumFractionDigits(2);  
     
    String sql ="select * from dig where id=1"; 
    ResultSet res = stmt.executeQuery(sql); 
    double digSum = 0 ; 
    double unDigSum =0 ; 
    double digSumAll = 0; 
    String digPer = "0%"; 
    String unDigPer = "0%"; 
    while(res.next()){ 
      digSum = res.getInt("digs"); 
      unDigSum = res.getInt("undigs"); 
    } 
    digSumAll = digSum + unDigSum; 
    if(digSumAll !=0 ){ 
      digPer = nf.format(digSum/digSumAll); 
      unDigPer = nf.format(unDigSum/digSumAll); 
    } 
     
    String str="
"; 
      str+=""; 
      str+="
很好
"; 
      str+=""+digPer+"("+digSum+")"; 
      str+="
"; 
      str+=""; 
      str+="
很差
"; 
      str+=""+unDigPer+"("+unDigSum+")"; 
      str+="
"; 
   
    return str; 
     
  } 
  /** 
   * Initialization of the servlet. 
 
   * 
   * @throws ServletException 
   *       if an error occurs 
   */ 
  public void init() throws ServletException { 
    try { 
      Class.forName("com.MySQL.jdbc.Driver"); 
      con = DriverManager.getConnection( 
          "jdbc:mysql://172.16.42.39:3306/dig", "root", "12345678"); 
      stmt = con.createStatement(); 
    } catch (Exception e) { 
      // TODO Auto-generated catch block 
      e.printStackTrace(); 
    } 
 
  } 
 
  public void closeCon() { 
    try { 
      stmt.close(); 
      con.close(); 
    } catch (SQLException e) { 
      // TODO Auto-generated catch block 
      e.printStackTrace(); 
    } 
 
  } 
} 

CREATE TABLE dig( 
 id INT PRIMARY KEY, 
 digs INT, 
 undigs INT 
); 
INSERT INTO dig VALUES(1,0,0);