Spring MVC - 表单处理示例

2023-07-24 16:16:52

环境搭建

环境：

Intellij IDEA
Spring MVC

完整的项目文件结构如下所示：

Student.java

package com.ktao.controller;

public class Student {

    private Integer age;

    private String name;

    private Integer id;

    public void setAge(Integer age) {

        this.age = age;

    }

    public Integer getAge() {

        return age;

    }

    public void setName(String name) {

        this.name = name;

    }

    public String getName() {

        return name;

    }

    public void setId(Integer id) {

        this.id = id;

    }

    public Integer getId() {

        return id;

    }

}

StudentController.java

package com.ktao.controller;

import org.springframework.stereotype.Controller;

import org.springframework.ui.ModelMap;

import org.springframework.web.bind.annotation.ModelAttribute;

import org.springframework.web.bind.annotation.RequestMapping;

import org.springframework.web.bind.annotation.RequestMethod;

import org.springframework.web.portlet.ModelAndView;

@Controller

public class StudentController {

    @RequestMapping(value = "/student",method = RequestMethod.GET)

    public ModelAndView student(){

        return new ModelAndView("student","command",new Student());

    }

    @RequestMapping(value = "/addStudent", method = RequestMethod.POST)

    public String addStudent(Student student,ModelMap model) {

        model.addAttribute("name", student.getName());

        model.addAttribute("age", student.getAge());

        model.addAttribute("id", student.getId());

        return "result";

    }

}

配置文件

web.xml

FormHanding-servlet.xml

<?xml version="1.0" encoding="UTF-8"?>

<beans xmlns="http://www.springframework.org/schema/beans"

       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

       xmlns:context="http://www.springframework.org/schema/context"

       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">

    <context:component-scan base-package="com.ktao.controller"/>

    <!--视图解析器-->

    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">

        <property name="prefix" value="/WEB-INF/jsp/"/>

        <property name="suffix" value=".jsp"/>

    </bean>

</beans>

视图文件

student.jsp

<%@ page contentType="text/html; charset=UTF-8" %>

<%@taglib uri="http://www.springframework.org/tags/form" prefix="form"%>

<jsp:useBean id="command" class="com.ktao.controller.Student" scope="request" ></jsp:useBean>

<html>

<head>

    <title>Spring MVC表单处理</title>

</head>

<body>

<h2>Student Information</h2>

<form:form method="POST" action="addStudent">

    <table>

        <tr>

            <td><form:label path="name">名字：</form:label></td>

            <td><form:input path="name" /></td>

        </tr>

        <tr>

            <td><form:label path="age">年龄：</form:label></td>

            <td><form:input path="age" /></td>

        </tr>

        <tr>

            单<td><form:label path="id">编号：</form:label></td>

            <td><form:input path="id" /></td>

        </tr>

        <tr>

            <td colspan="2">

                <input type="submit" value="提交表单"/>

            </td>

        </tr>

    </table>

</form:form>

</body>

</html>

result.jsp

<%@ page contentType="text/html; charset=UTF-8" %>

<%@taglib uri="http://www.springframework.org/tags/form" prefix="form"%>

<html>

<head>

    <title>Spring MVC表单处理</title>

</head>

<body>

<h2>提交的学生信息如下 - </h2>

<table>

    <tr>

        <td>名称：</td>

        <td>${name}</td>

    </tr>

    <tr>

        <td>年龄：</td>

        <td>${age}</td>

    </tr>

    <tr>

        <td>编号：</td>

        <td>${id}</td>

    </tr>

</table>

</body>

</html>

运行结果

报错分析

错误1

错因：lib文件包不完整

解决方法：

错误2

javax.servlet.jsp.JspTagException: Neither BindingResult nor plain target object for bean name 'command' available as request attribute

方法：

1为抛出异常原因，2为异常解决方法。

1. 原因：进入spring：bind标签源码你可以看到

Object target = requestContext.getModelObject(beanName);
if (target == null) {
throw new IllegalStateException("Neither BindingResult nor plain target object for bean name '" +
beanName + "' available as request attribute");
}

beanName= <spring:bind path="command.spjg">的绿色部分

如果你是直接对某个页面进行请求，那么request中还没command这个对象

在页面上加上

<jsp:useBean id="command" class="com.mvc.domain.BlogForm" scope="request" ></jsp:useBean>

红色部分填上你的绑定类

解释一下，这个command类似于struts的引用的form对象，使用jsp:userBean是引用在spring-mvc.xml配置文件中的command对象。

码农公寓