@Valid 注释在我的 spring MVC maven 项目中不起作用

Question

我正在尝试使用 @Valid 和 @Size 注释来验证我的 JSP 页面字段长度，但它们不起作用。我知道我错过了什么吗？

请在下面找到我的代码。

Student.java（pojo 类）

package com.vijay.controllerCAMVC;

import java.util.ArrayList;
import java.util.Date;

import javax.validation.Valid;
import javax.validation.constraints.NotNull;
import javax.validation.constraints.Size;

import jdk.nashorn.internal.objects.annotations.SpecializedFunction;

public class Student {

    @Size(min=2, max=20)
    private String firstname;

//    @Size(min=2, max=20, message='Size.student1.lastname')
    **@Size(min=2, max=20)** 
//    , message="Please enter lastname length between {min} and {max}") 
    private String lastname;

    private Date dateofbirth;
    private ArrayList<String> courses;

    private Address address;

    public Date getDateofbirth() {
        return dateofbirth;
    }
    public void setDateofbirth(Date string) {
        this.dateofbirth = string;
    }
    public ArrayList<String> getCourses() {
        return courses;
    }
    public void setCourses(ArrayList<String> courses) {
        this.courses = courses;
    }


    public String getFirstname() {
        return firstname;
    }
    public void setFirstname(String firstname) {
        this.firstname = firstname;
    }
    public String getLastname() {
        return lastname;
    }
    public void setLastname(String lastname) {
        this.lastname = lastname;
    }


    public Address getAddress() {
        return address;
    }
    public void setAddress(Address address) {
        this.address = address;
    }



}

控制器类代码：

package com.vijay.controllerCAMVC;

import java.beans.PropertyEditor;
import java.text.DateFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Map;

import javax.validation.Valid;

import org.springframework.beans.propertyeditors.CustomDateEditor;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.validation.BindingResult;
import org.springframework.web.bind.WebDataBinder;
import org.springframework.web.bind.annotation.InitBinder;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.servlet.ModelAndView;

@Controller
public class HelloWorld2 {


//  avoiding binding of problem fields @ModelAttribute auto binding case, always in 1st position in controller
    @InitBinder
    public void initbinder( WebDataBinder webdatabinder){
        webdatabinder.setDisallowedFields( new String[] {"courses"} );
//      property editors
        SimpleDateFormat df = new SimpleDateFormat("mm-dd-yyyy");
        webdatabinder.registerCustomEditor(Date.class, "dateofbirth", new CustomDateEditor(df, false) );

//      String editor for custom property editors defined by user specific i.e StringPropertyEditor.java
        webdatabinder.registerCustomEditor(String.class, "firstname", new StringPropertyEditor() );
    }


    @SuppressWarnings({ "deprecation", "deprecation" })
    @RequestMapping(value = "/Submissionform.html", params = "DELETE", method = RequestMethod.POST)
    public ModelAndView modelview3(
            /*
             * @RequestParam(name = "firstname", required = false, defaultValue
             * = "ENter Name") String firstname,
             * 
             * @RequestParam(name = "lastname", required = false, defaultValue =
             * "Default2") String lastname
             */
            // @RequestParam Map<String, String> reqparams) {

//      @Valid  Before do data binding from JSP to model please apply validations using annotations
        **@Valid**  @ModelAttribute("student1") Student student1, BindingResult result) {
        // similar to move corresponding using name

        if (result.hasErrors()) {
            ModelAndView modelandview = new ModelAndView("ApplicationForm");
            return modelandview;
        }

        ModelAndView modelandview = new ModelAndView("DeleteForm");

        // modelandview.addObject("msg", "Congratulation on Applicaiton
        // Submission for");

        // Student student1 = new Student();
        // student1.setFirstname(reqparams.get("firstname"));
        // student1.setLastname(reqparams.get("lastname"));
        //
        // DateFormat df = new SimpleDateFormat("dd/mm/yyy");
        // Date dateofbirth = null;
        //
        // try {
        // dateofbirth = (Date) df.parse(reqparams.get("dateofbirth"));
        // } catch (ParseException e) {
        // e.printStackTrace();
        // }
        // student1.setDateofbirth(dateofbirth);
        // modelandview.addObject("student1", student1);
        //

        return modelandview;
    }

    // common attributes which gets auto added to all methods in controller &
    // executes 1st
    @ModelAttribute
    public void addcommonmodelattributes(Model model1) {
        model1.addAttribute("msg", "Congratulation on Applicaiton Submission for");
    }
}

我的 JSP 文件：强文本

<%@ taglib prefix="form" uri="http://www.springframework.org/tags/form" %>
<%-- page language="java" contentType="text/html; charset=ISO-8859-1" --%>
<%--    pageEncoding="ISO-8859-1"%> --%>
<!-- <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> -->
<html>

<body>
    <h1>Student Application Form</h1>

<form:errors path="student1.*"/>

    <form action="/SimpleSpringMVC2/Submissionform.html" method="post">

<table>
<tr>
<td> First Name : </td> <td> <input name="firstname" type="text" /> </td>
</tr>

<tr>
<td> Last Name : </td> <td> <input name="lastname" type="text" /> </td>
</tr>

<tr>
<td> Date of birth : </td> <td> <input name="dateofbirth" type="text" class="date" />
' </td>
</tr>

<tr>
<td> Courses : </td> <td>  <select name="courses" multiple>
                <option value="C">C</option>
                <option value="C++">C++</option>
                <option value="Java">Java</option>
            </select> </td>
</tr>

</table>

<table>
<tr>
<td>City : </td> <td><input type="text" name="address.city"></td>
<td>State : </td> <td><input type="text" name="address.state"></td>
<td>PinCode : </td> <td><input type="text" name="address.picode"></td>
</tr>
</table>

        <input type="submit" name="CREATE" value="CREATE" /> 
        <input type="submit" name="MODIFY" value="MODIFY" /> 
        <input type="submit" name="DELETE" value="DELETE" />

    </form>

</body>
</html>

Answer 1

这个问题并没有真正解释验证是如何不起作用的，但如果我猜测一下，那将是 lastname 上缺少 @NotNull()。

@Size(min=2, max=20)
private String lastname;

表示lastname 可以是null 或不是null，但长度在2 到20 之间。但是听起来，null 不是一个可接受的值，所以它应该是

@NotNull
@Size(min=2, max=20)
private String lastname;