我已经创建了这个算法，其中两个团队burnley和manchester_united正在进行匹配，他们根据表中给出的玩家overall来评分目标。
我有这两个表：
manchester_united：列名称=数字，名称，整体，目标burnley：列名称=数字，名称，整体，目标当我执行我的代码时，它在浏览器中显示更新的值，但在goals列的数据库表中没有更新这些值。
下面是我的servlet代码：
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.sql.*;
import java.util.Random;
public class gg extends HttpServlet {
protected void processRequest(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html;charset=UTF-8");
PrintWriter out = response.getWriter();
int a[]=new int[11];
int b[]=new int[11];
int count1=0 ,count2=0;
String up;
int goals1[]= new int[11];
int goals2[]=new int[11];
Random rand = new Random();
int x=0,y=0;
int player1=0,player2=0;
Statement stmt=null;
String sql3[] =new String[21];
String sql4[] =new String[21];
String sql1="select * from manchester_united";
try{
Class.forName("com.mysql.jdbc.Driver");
Connection con = DriverManager.getConnection("jdbc:mysql://localhost:3306/log","root","root");
stmt=con.createStatement();
ResultSet rs=stmt.executeQuery(sql1);
while (rs.next())
{
a[count1]=rs.getInt("overall");
goals1[count1]=rs.getInt("goals");
out.println("<br>");
out.println("a["+(count1+1)+"] = "+a[count1]+" ");
out.println("<br>");
out.println("goals1["+(count1+1)+"] = "+goals1[count1]+" ");
count1++;
}
//count=0;
out.println("<br>");
out.println("<br>");
String sql2="select * from burnley";
//stmt=con.createStatement();
rs=stmt.executeQuery(sql2);
while(rs.next())
{
b[count2]=rs.getInt("overall");
goals2[count2]=rs.getInt("goals");
out.println("<br>");
out.println("b["+(count2+1)+"] = "+b[count2]+" ");
out.println("<br>");
out.println("goals2["+(count2+1)+"] = "+goals2[count2]+" ");
count2++;
}
for (int i=0;i<11;i++)
{
player1=rand.nextInt(11);
player2=rand.nextInt(11);
if (a[player1]>b[player2])
{
int goal=rand.nextInt(10)+1;
if (a[player1]>=90)
{
if (goal==1 || goal==2 ||goal==4 || goal==5 ||goal==7 || goal==8 ||goal==9 || goal==10)
{
x=x+1;
goals1[player1]++;
sql3[i]="UPDATE `manchester_united` SET `goals`=? WHERE `number`=?";
PreparedStatement ps = con.prepareStatement(sql3[i]);
ps.setInt(1,goals1[player1]);
ps.setInt(2,player1);
}
}
else if (a[player1]>=80 && a[player1]<90)
{
if (goal==1 || goal==2 || goal==4 || goal==5 || goal==7 || goal==9 || goal==10)
{
x=x+1;
goals1[player1]++;
sql3[i]="UPDATE `manchester_united` SET `goals`=? WHERE `number`=?";
PreparedStatement ps = con.prepareStatement(sql3[i]);
ps.setInt(1,goals1[player1]);
ps.setInt(2,player1);
}
}
else if (a[player1]>=70 && a[player1]<80)
{
if (goal==1 || goal==2 || goal==4 || goal==7 || goal==8 || goal==10)
{
x=x+1;
goals1[player1]++;
sql3[i]="UPDATE `manchester_united` SET `goals`=? WHERE `number`=?";
PreparedStatement ps = con.prepareStatement(sql3[i]);
ps.setInt(1,goals1[player1]);
ps.setInt(2,player1);
}
}
else if (a[player1]>=60 && a[player1]<70)
{
if (goal==1 || goal==2 ||goal==5 || goal==8 ||goal==9)
{
x=x+1;
goals1[player1]++;
sql3[i]="UPDATE `manchester_united` SET `goals`=? WHERE `number`=?";
PreparedStatement ps = con.prepareStatement(sql3[i]);
ps.setInt(1,goals1[player1]);
ps.setInt(2,player1);
}
}
else if (a[player1]>=50 && a[player1]<60)
{
if (goal==1 ||goal==4 || goal==5 || goal==8)
{
x=x+1;
goals1[player1]++;
sql3[i]="UPDATE `manchester_united` SET `goals`=? WHERE `number`=?";
PreparedStatement ps = con.prepareStatement(sql3[i]);
ps.setInt(1,goals1[player1]);
ps.setInt(2,player1);
}
}
else
{
if (goal==1 || goal==5 || goal==7)
{
x=x+1;
goals1[player1]++;
sql3[i]="UPDATE `manchester_united` SET `goals`=? WHERE `number`=?";
PreparedStatement ps = con.prepareStatement(sql3[i]);
ps.setInt(1,goals1[player1]);
ps.setInt(2,player1);
}
}
}
else
{
int goal=rand.nextInt(10)+1;
if (b[player2]>=90)
{
if (goal==1 || goal==2 ||goal==4 || goal==5 ||goal==7 || goal==8 ||goal==9 || goal==10)
{
y=y+1;
goals2[player2]++;
sql4[i]="UPDATE `burnley` SET `goals`=? WHERE `number`=?";
PreparedStatement ps = con.prepareStatement(sql4[i]);
ps.setInt(1,goals2[player2]);
ps.setInt(2,player2);
}
}
else if (b[player2]>=80 && b[player2]<90)
{
if (goal==1 || goal==2 || goal==4 || goal==5 || goal==7 || goal==9 || goal==10)
{
y=y+1;
goals2[player2]++;
sql4[i]="UPDATE `burnley` SET `goals`=? WHERE `number`=?";
PreparedStatement ps = con.prepareStatement(sql4[i]);
ps.setInt(1,goals2[player2]);
ps.setInt(2,player2);
}
}
else if (b[player2]>=70 && b[player2]<80)
{
if (goal==1 || goal==2 || goal==4 || goal==7 || goal==8 || goal==10)
{
y=y+1;
goals2[player2]++;
sql4[i]="UPDATE `burnley` SET `goals`=? WHERE `number`=?";
PreparedStatement ps = con.prepareStatement(sql4[i]);
ps.setInt(1,goals2[player2]);
ps.setInt(2,player2);
}
}
else if (b[player2]>=60 && b[player2]<70)
{
if (goal==1 || goal==2 ||goal==5 || goal==8 ||goal==9)
{
y=y+1;
goals2[player2]++;
sql4[i]="UPDATE `burnley` SET `goals`=? WHERE `number`=?";
PreparedStatement ps = con.prepareStatement(sql4[i]);
ps.setInt(1,goals2[player2]);
ps.setInt(2,player2);
}
}
else if (b[player2]>=50 && b[player2]<60)
{
if (goal==1 ||goal==4 || goal==5 || goal==8)
{
y=y+1;
goals2[player2]++;
sql4[i]="UPDATE `burnley` SET `goals`=? WHERE `number`=?";
PreparedStatement ps = con.prepareStatement(sql4[i]);
ps.setInt(1,goals2[player2]);
ps.setInt(2,player2);
}
}
else
{
if (goal==1 || goal==5 || goal==7)
{
y=y+1;
goals2[player2]++;
sql4[i]="UPDATE `burnley` SET `goals`=? WHERE `number`=?";
PreparedStatement ps = con.prepareStatement(sql4[i]);
ps.setInt(1,goals2[player2]);
ps.setInt(2,player2);
}
}
}
}
}
catch (Exception e)
{
e.printStackTrace();
}
out.println("<br>");
out.println("Team1= "+x+" and Team2= "+y+"<br>");
for(int j=0;j<11;j++)
{
out.println("<br>goals1= "+goals1[j]+" and goals2= "+goals2[j]);
}
}
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
processRequest(request, response);
}
}
答案 0 :(得分：0)
您需要添加executeUpdate()才能实际更新数据。