请java高手帮帮忙，帮我解决一下问题，谢谢先！

这是一个Struts2的编程小项目，有三个类,具体如下：
MapForm类：
package sys.whpart.action.web;import java.util.Map;public class MapForm
{
    private String studentId;
    private UserInfo user;
    private Map<String,UserInfo> students;    public String getStudentId(){
        return studentId;
    }    public void setStudentId(String studentId){
        this.studentId = studentId;
    }    public Map<String, UserInfo> getStudents(){
        return students;
    }    public void setStudents(Map<String, UserInfo> students){
        this.students = students;
    }    public UserInfo getUser(){
        return user;
    }    public void setUser(UserInfo user){
        this.user = user;
    }
}UserInfo类：
package sys.whpart.action.web;public class UserInfo
{
    private String name,sex;    public String getName(){
        return name;
    }    public void setName(String name){
        this.name = name;
    }    public String getSex(){
        return sex;
    }    public void setSex(String sex){
        this.sex = sex;
    }
}MapAction类：
package sys.whpart.action.web;
import java.util.HashMap;
import java.util.Map;import javax.servlet.http.HttpSession;import org.apache.struts2.ServletActionContext;
import org.apache.struts2.convention.annotation.Action;
import org.apache.struts2.convention.annotation.Namespace;
import org.apache.struts2.convention.annotation.Result;import sys.whpart.action.web.MapAction;import com.opensymphony.xwork2.ActionSupport;
import com.opensymphony.xwork2.ModelDriven;@Namespace("/example")
public class MapAction extends ActionSupport 
{
    MapForm form=new MapForm();
    private static Map<String,UserInfo> students=new HashMap<String,UserInfo>();
    
    private MapForm getForm(){
        return form;
    }    public void setForm(MapForm form){
        this.form = form;
    }
    @Action(value = "show", results = { @Result(name =SUCCESS, location = "/WEB-INF/example/Map.jsp") })
    public String show(){
        HttpSession session=ServletActionContext.getRequest().getSession();
        Map<String,UserInfo> students=(Map<String,UserInfo>)session.getAttribute("students");
        form.setStudents(students);
        return SUCCESS;
    }
    @Action(value = "add", results = { @Result(name =SUCCESS, location = "/WEB-INF/example/Map.jsp") })
    public String add(){
        String id=form.getStudentId();
        UserInfo info=form.getUser();
        HttpSession session=ServletActionContext.getRequest().getSession();
        Map<String,UserInfo> students=(Map<String,UserInfo>)session.getAttribute("students");
        if(students==null){
            students=new HashMap<String,UserInfo>();
            session.setAttribute("students", students);
        }
        students.put(id, info);
        form.setStudents(students);
        
        return SUCCESS;
    }
    
    @Action(value = "save", results = {@Result(name =SUCCESS, location = "/WEB-INF/example/Result.jsp") })
    public String save(){
        HttpSession session=ServletActionContext.getRequest().getSession();
        Map<String,UserInfo> students=(Map<String,UserInfo>)session.getAttribute("students");
        session.removeAttribute("students");
        session.setAttribute("students",form.getStudents());
        return SUCCESS;
    }
    public String remove(){
        
        return SUCCESS;
    }
    
    public String clear(){
        String id=form.getStudentId();
        UserInfo info=form.getUser();
        HttpSession session=ServletActionContext.getRequest().getSession();
        Map<String,UserInfo> students=(Map<String,UserInfo>)session.getAttribute("students");
        students.put(id, info);
        form.setStudents(students);
        students.clear();
        return SUCCESS;
    }    public MapForm getModel(){
      
        return form;
    }}还有一个jsp页面Map.jsp,请问我要实现添加的功能，我的MapAction有问题吗，jsp页面要怎么写，请帮帮我吧，我是初学者，已经想到头都破了，还是做不成功。