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两种实现方式:1)sql,2)java
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1)sql语句-mysql
SELECT NAME,num,ranking
FROM (SELECT NAME,num,
IF (num =@num ,@ranking ,@ranking :=@ranking + 1)AS ranking,
@num := num
FROM score,
(SELECT @ranking := 0,@num:=-1) tmp
ORDER BY num DESC
)tmp
2) java实现
public static void main(String[] args) {
//初始化数据
ListRank ranks = Arrays.asList(new Rank("薛之谦", 100l),
new Rank("陈奕迅", 102l),
new Rank("田馥甄", 100l),
new Rank("周杰伦", 99l));
//按分数降序排序
ranks.sort((r1, r2) - r2.getNum().compareTo(r1.getNum()));
//计算排名
int ranking = 0;
long num = -1;
for (Rank rank : ranks) {
rank.setRanking(rank.getNum() == num ? ranking : ++ranking);
num = rank.getNum();
}
//输出
ranks.forEach(o - System.out.println(o.getName() + ";" + o.getNum() + ":" + o.getRanking()));
}
import java.lang.reflect.Array;
import java.util.Arrays;
import java.util.Scanner;
public class Test {
public static void Ballots() {
Scanner sc = new Scanner(System.in);
int[] count = new int[7];
String instr = "";
int spoiled = 0, sum = 0;
for (int i = 0; i count.length; i++) {
count[i] = 0;
}
System.out.println("输入方框数字代码投票给歌手,输入.结束 ");
do {
System.out.print("张学友[0], 刘德华[1], 小刚[2], 孙燕姿[3], 梁静茹[4], 王杰[5], 刘若英[6])? ");
instr = sc.nextLine();
if (instr.equals("0")) {
count[0]++;
} else if (instr.equals("1")) {
count[1]++;
} else if (instr.equals("2")) {
count[2]++;
} else if (instr.equals("3")) {
count[3]++;
} else if (instr.equals("4")) {
count[4]++;
} else if (instr.equals("5")) {
count[5]++;
} else if (instr.equals("6")) {
count[6]++;
} else {
if (!instr.equals(".")) {
spoiled++;
}
}
} while (!instr.equals("."));
System.out.println("投票结束,结果是 : \n");
System.out.println("歌手\t\t得票数");
System.out.println("======\t\t=========");
for (int i = 0; i count.length; i++) {
if (i == 0) {
System.out.println(" 张学友 \t\t" + count[i]);
} else if (i == 1) {
System.out.println(" 刘德华 \t\t" + count[i]);
} else if (i == 2) {
System.out.println(" 小刚 \t\t" + count[i]);
} else if (i == 3) {
System.out.println(" 孙燕姿 \t\t" + count[i]);
} else if (i == 4) {
System.out.println(" 梁静茹 \t\t" + count[i]);
} else if (i == 5) {
System.out.println(" 王杰 \t\t" + count[i]);
}else if (i == 6) {
System.out.println(" 刘若英 \t\t" + count[i]);
}
}
for (int t : count) {
sum += t;
}
System.out.println("弃权票数: " + spoiled);
System.out.println("总票数: " + sum);
}
public static void main(String[] args) {
System.out.println("投票开始:");
Scanner sc = new Scanner(System.in);
String is = "";
do {
Ballots();
System.out.println("继续第二轮投票? (y/n):");
is = sc.nextLine();
} while (is.equals("y"));
}
}
定义三个变量记录每个人的投票数。点击投票按钮后,根据checkbox的勾选情况将三个变量累加。点击查看按钮时展示这三个变量
import java.io.BufferedReader;
import java.io.InputStreamReader;
public class Vote {
public static void main(String args[]) {
try {
String[] persons = new String[]{"1","2","3"};
Integer[] votes = new Integer[]{0,0,0};
BufferedReader sin = new BufferedReader(new InputStreamReader(
System.in));
String readline;
System.out.println("================投票开始===============");
System.out.println("请按1,2,3投票,Enter确认");
System.out.println("按0--Enter结束投票,公布结果\n");
readline = sin.readLine(); // 从系统标准输入读入一字符串
while (!readline.equals("0")) {
String voteStr = readline;
if(persons[0].equals(voteStr)){
votes[0] +=1;
}else if(persons[1].equals(voteStr)){
votes[1] +=1;
}else if(persons[2].equals(voteStr)){
votes[2] +=1;
}else{
System.out.println("无效的投票!");
}
readline = sin.readLine(); // 从系统标准输入读入一字符串
} // 继续循环
System.out.println("================投票结束===============");
System.out.println("================结果公布===============");
System.out.println(persons[0]+"================"+persons[1]+"==============="+persons[2]);
System.out.println(votes[0]+"================"+votes[1]+"==============="+votes[2]);
} catch (Exception e) {
System.out.println("Error" + e); // 出错,则打印出错信息
}
}
}
把投票的信息放在 ServletContext对象 中。也就是 JSP 内置对象中的application对象。因为投票信息是所有用户都要看的信息,所以要把他放在 ServletContext对象 中。这样只要是 应用一加载就会创建 ServletContext对象 直到应用销毁,也就是服务器关闭时,ServletContext对象 才销毁。这样就使得所有用户公用一个对象存储信息。具体的实现那要根据你自己的需求,具体设计。
public class CServlet extends HttpServlet {public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {int n = 0;ServletContext application = getServletContext();Integer num = (Integer) application.getAttribute("num");if (num != null) {n = num;}application.setAttribute("num", ++n);response.setContentType("text/html;charset=utf-8");PrintWriter out = response.getWriter();out.println("你是第" + n + "个访问者");}}
上面是个类似的例子。你可以参考一下。package servlet;import java.io.IOException;import java.io.PrintWriter;import javax.servlet.ServletContext;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;这是需要导入的包