code review

package service;

import imp.UserDaoImp;

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 bean.User;
import dao.UserDao;

public class admin_adduser extends HttpServlet {

    /**
     * Constructor of the object.
     */
    public admin_adduser() {
        super();
    }

    /**
     * Destruction of the servlet. <br>
     */
    public void destroy() {
        super.destroy(); // Just puts "destroy" string in log
        // Put your code here
    }

    /**
     * The doGet method of the servlet. <br>
     *
     * This method is called when a form has its tag value method equals to get.
     * 
     * @param request the request send by the client to the server
     * @param response the response send by the server to the client
     * @throws ServletException if an error occurred
     * @throws IOException if an error occurred
     */
    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {

        response.setContentType("text/html");
        PrintWriter out = response.getWriter();
        out.println("<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">");
        out.println("<HTML>");
        out.println("  <HEAD><TITLE>A Servlet</TITLE></HEAD>");
        out.println("  <BODY>");
        out.print("    This is ");
        out.print(this.getClass());
        out.println(", using the GET method");
        out.println("  </BODY>");
        out.println("</HTML>");
        out.flush();
        out.close();
    }

    /**
     * The doPost method of the servlet. <br>
     *
     * This method is called when a form has its tag value method equals to post.
     * 
     * @param request the request send by the client to the server
     * @param response the response send by the server to the client
     * @throws ServletException if an error occurred
     * @throws IOException if an error occurred
     */
    public void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {

        response.setContentType("text/html");
        request.setCharacterEncoding("utf-8");
        response.setCharacterEncoding("utf-8");
        String uid=request.getParameter("uid");
        String uname=request.getParameter("uname");
        String uclass=request.getParameter("uclass");
        String upassword=request.getParameter("upassword");
        
        User user=new User();
        user.setuId(uid);
        user.setuName(uname);
        user.setuClass(uclass);
        user.setuPassword(upassword);
        UserDao userdao=new UserDaoImp();
        int result=userdao.addUser(user);
        System.out.println(result);
        if(result>0){
            PrintWriter out=response.getWriter();
            out.print("<script type='text/javascript'>"+
                      "alert('添加成功');window.location.href='../admin_manageruser.jsp';</script>");
            out.flush();
            out.close();
        }else{
            PrintWriter out=response.getWriter();
            out.print("<script type='text/javascript'>"+
                      "alert('添加失败');window.location.href='../admin_manageruser.jsp';</script>");
            out.flush();
            out.close();
        }
        String[] error = { "姓名未输入", "班级未输入", "学号未输入", "密码未输入" };
        for (int i = 1; i < error.length; i++) {
            System.out.println(error[i]);
        }

        
    }

    /**
     * Initialization of the servlet. <br>
     *
     * @throws ServletException if an error occurs
     */
    public void init() throws ServletException {
        // Put your code here
    }

}
每一段代码都要反复考量，尽量减少没必要的，代码中的判断语句没有标注是判断那种变量，对其他Java文件会有连带影响，要注意关联