準備済みSQL命令でデータベースアクセスを効率化する：JavaTips 〜JSP／サーブレット編

package to.msn.wings;
 
import java.io.IOException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
 
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
 
public class PrepareSql extends HttpServlet {
  public void doPost(HttpServletRequest request,HttpServletResponse response)
    throws ServletException,IOException {
      Connection db=null;
      PreparedStatement objSql=null;
      try {
        request.setCharacterEncoding("Windows-31J");
        Class.forName("org.gjt.mm.mysql.Driver");
        db=DriverManager.getConnection("jdbc:mysql://localhost/
atit?user=root&password=root&useUnicode=true&characterEncoding=Windows-31J");
        objSql=db.prepareStatement("UPDATE books SET title=?,price=? WHERE isbn=?");
        for(int i=1;i<11;i++){
          objSql.setString(1,request.getParameter("title" + i));
          objSql.setString(2,request.getParameter("price" + i));
          objSql.setString(3,request.getParameter("isbn" + i));
          objSql.executeUpdate();
        }
      } catch(Exception e) {
        throw new ServletException(e);
      } finally {
        try {
          if(objSql!=null){objSql.close();}
          if(db!=null)    {db.close();}
        } catch(Exception e) {
          throw new ServletException(e);
        }
      }
  }
}