在spring mvc中注册

我是spring新手，尝试创建注册和登录模块时遇到了许多问题

jsp:-注册表的视图

<div class="container">
  <form:form action="doRegister" method="post" modelAttribute="Login">
  <h2>Create a FREE account</h2>
  <h3>already have an account?<a href="/SurveyIt/Login"><span> Login </span></a></h3>
  <div class="form-group">
    <label for="username">Username:</label>
    <form:input type="text" class="form-control" path="username"/>
  </div>
  <div class="form-group">
    <label for="pwd">Password:</label>
    <form:input type="password" class="form-control" path="password"/>
  </div>
  <div class="form-group">
    <label for="email">Email address:</label>
    <form:input type="email" class="form-control" path="email"/>
  </div>
  <div class="form-group">
    <label for="fname">First Name:</label>
    <form:input type="text" class="form-control" path="firstname"/>
  </div>
  <div class="form-group">
    <label for="lname">Last Name:</label>
    <form:input type="text" class="form-control" path="lastname"/>
  </div>
  <button type="submit" class="btn btn-primary">Submit</button>
</form:form>

注册DAO实现类：-这是注册DAO的实现类。如果未注册，有2种方法检查用户是否存在

@Autowired
    DataSource datasource;

    @Autowired
    JdbcTemplate jdbctemplate;
    public void doinsert(Login login)
    {
        String sql = "insert into login (username, password, email) values (?,?,?)";
                jdbctemplate.update(sql, new Object[] {login.getUsername(),login.getPassword(),login.getEmail()});
    }
    public Login validateUser(Login login)
    {
        String sql = "select * from login where username = ? and password = ?";
        List<Login> user = null;
    /*  System.out.println("username"+ login.getUsername());
        System.out.println("password"+ login.getPassword());
        System.out.println("email"+ login.getEmail());
        System.out.println("firstname"+ login.getFirstname());
        System.out.println("lastname"+ login.getLastname());   */
        user = jdbctemplate.query(sql, new Object[] {login.getUsername(),login.getPassword()}, new LoginMapper());
        return user.size() > 0 ? user.get(0):null;
    }

}

我的问题是执行时显示错误

org.springframework.web.util.NestedServletException:请求处理失败；嵌套异常是java.lang.NullPointerException org.springframework.web.servlet.FrameworkServlet.processRequest（FrameworkServlet.java:1013） org.springframework.web.servlet.FrameworkServlet.doPost（FrameworkServlet.java:908） javaservlet.http.HttpServlet.service（HttpServlet.java:652） org.springframework.web.servlet.FrameworkServlet.service（FrameworkServlet.java:882） javaservlet.http.HttpServlet.service（HttpServlet.java:733） org.apache.tomcat.websocket.server.WsFilter.doFilter（WsFilter.java:52）

@Autowired
    DataSource datasource;

    @Autowired
    JdbcTemplate jdbctemplate;
    public void doinsert(Login login)
    {
        String sql = "insert into login (username, password, email) values (?,?,?)";
                jdbctemplate.update(sql, new Object[] {login.getUsername(),login.getPassword(),login.getEmail()});
    }
    public Login validateUser(Login login)
    {
        String sql = "select * from login where username = ? and password = ?";
        List<Login> user = null;
    /*  System.out.println("username"+ login.getUsername());
        System.out.println("password"+ login.getPassword());
        System.out.println("email"+ login.getEmail());
        System.out.println("firstname"+ login.getFirstname());
        System.out.println("lastname"+ login.getLastname());   */
        user = jdbctemplate.query(sql, new Object[] {login.getUsername(),login.getPassword()}, new LoginMapper());
        return user.size() > 0 ? user.get(0):null;
    }

public class LoginMapper implements RowMapper{

    public Object mapRow(ResultSet rs, int arg1) throws SQLException {
        Login login = new Login();
        login.setUsername(rs.getString("username"));
        login.setPassword(rs.getString("password"));
        login.setEmail(rs.getString("email"));
        login.setFirstname(rs.getString("firstname"));
        login.setLastname(rs.getString("lastname"));
        return login;
    }