Spring 教程

Spring MVC表单下拉列表

Spring MVC表单下拉列表包含元素列表。此标记生成HTML select元素。它允许将数据绑定到所选元素。

语法

<form:select path="name">

以下是用于选择选项的其他一些标签。

选项标签

此标签生成HTML选项标签。每个标签都包含一个可由用户选择的值。

语法

<form:option value="abc" label="xyz"/>

选项标签

此标签生成HTML选项标签的列表。每个标签包含用户选择的元素列表。

语法

<form:options items="${elementList}" itemValue="abc" itemLabel="xyz"/>

Spring MVC表单下拉列表示例

1、将依赖项添加到pom.xml文件。

          <!-- https://mvnrepository.com/artifact/org.springframework/spring-webmvc -->
<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-webmvc</artifactId>
    <version>5.1.1.RELEASE</version>
</dependency>
    <!-- https://mvnrepository.com/artifact/javax.servlet/javax.servlet-api -->
<dependency>  
    <groupId>javax.servlet</groupId>  
    <artifactId>servlet-api</artifactId>  
    <version>3.0-alpha-1</version>  
</dependency>
    <!-- https://mvnrepository.com/artifact/javax.servlet/jstl -->
<dependency>
    <groupId>javax.servlet</groupId>
    <artifactId>jstl</artifactId>
    <version>1.2</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.apache.tomcat/tomcat-jasper -->
<dependency>
    <groupId>org.apache.tomcat</groupId>
    <artifactId>tomcat-jasper</artifactId>
    <version>9.0.12</version>
</dependency>

2、创建bean类

Reservation.java 

package com.nhooo;
public class Reservation {
    private String firstName;
    private String lastName;
    private String Gender;
    private String[] Food;
    private String cityFrom;
    private String cityTo;
    public Reservation()
    {       
    }
    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 String getGender() {
        return Gender;
    }
    public void setGender(String gender) {
        Gender = gender;
    }
    public String[] getFood() {
        return Food;
    }
    public void setFood(String[] food) {
        Food = food;
    }   
    public String getCityFrom() {
    return cityFrom;
}
public void setCityFrom(String cityFrom) {
    this.cityFrom = cityFrom;
}
public String getCityTo() {
    return cityTo;
}
public void setCityTo(String cityTo) {
    this.cityTo = cityTo;
}   
}

3、创建控制器类

ReservationController.java 

package com.nhooo;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.bind.annotation.RequestMapping;
@RequestMapping("/reservation")
@Controller
public class ReservationController {
    @RequestMapping("/bookingForm")
public String bookingForm(Model model)
{
      //create a reservation object 
    Reservation res=new Reservation();
      //provide reservation object to the model 
    model.addAttribute("reservation", res);
    return "reservation-page";
}
@RequestMapping("/submitForm")
public String submitForm(@ModelAttribute("reservation") Reservation res)
{
    return "confirmation-form";
}
}

4、在web.xml文件中提供控制器的条目

web.xml 

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0">
  <display-name>SpringMVC</display-name>
   <servlet>  
    <servlet-name>spring</servlet-name>  
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>  
    <load-on-startup>1</load-on-startup>    
</servlet>  
<servlet-mapping>  
    <servlet-name>spring</servlet-name>  
    <url-pattern>/</url-pattern>  
</servlet-mapping>  
</web-app>

5、在xml文件中定义Bean

spring-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"
    xmlns:mvc="http://www.springframework.org/schema/mvc"
    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
        http://www.springframework.org/schema/mvc
        http://www.springframework.org/schema/mvc/spring-mvc.xsd">
    <!-- Provide support for component scanning -->
    <context:component-scan base-package="com.nhooo" />
    <!--Provide support for conversion, formatting and validation -->
    <mvc:annotation-driven/>
    <!-- Define Spring MVC view resolver -->
     <bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="prefix" value="/WEB-INF/jsp/"></property>
        <property name="suffix" value=".jsp"></property>     
     </bean>
</beans>

6、创建请求的页面

index.jsp 

<!DOCTYPE html>
<html>
<head>
    <title>Railway Registration Form</title>
</head>
<body>
<a href="reservation/bookingForm">Click here for reservation.</a>
</body>
</html>

7、创建视图组件

reservation-page.jsp 

<%@ taglib prefix="form" uri="http://www.springframework.org/tags/form" %>
<!DOCTYPE html>
<html>
<head>
    <title>Reservation Form</title>
</head>
<h3>Railway Reservation Form</h3>
<body>
    <form:form action="submitForm" modelAttribute="reservation">
        First name: <form:input path="firstName" />      
        <br><br>
        Last name: <form:input path="lastName" />
        <br><br>
        Gender: 
        Male<form:radiobutton path="Gender" value="Male"/>
        Female<form:radiobutton path="Gender" value="Female"/>
        <br><br>
        Meals:
        BreakFast<form:checkbox path="Food" value="BreakFast"/>
        Lunch<form:checkbox path="Food" value="Lunch"/>
        Dinner<form:checkbox path="Food" value="Dinner"/>
        <br><br>
        Leaving from: <form:select path="cityFrom">
        <form:option value="Ghaziabad" label="Ghaziabad"/>
        <form:option value="Modinagar" label="Modinagar"/>
        <form:option value="Meerut" label="Meerut"/>
        <form:option value="Amristar" label="Amristar"/>
        </form:select>
        <br><br>
        Going to: <form:select path="cityTo">
        <form:option value="Ghaziabad" label="Ghaziabad"/>
        <form:option value="Modinagar" label="Modinagar"/>
        <form:option value="Meerut" label="Meerut"/>
        <form:option value="Amristar" label="Amristar"/>
        </form:select>
        <br><br>
        <input type="submit" value="Submit" />
    </form:form>
</body>
</html>

confirmation-page.jsp 

<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<!DOCTYPE html>
<html>
<body>
<p>Your reservation is confirmed successfully. Please, re-check the details.</p>
First Name : ${reservation.firstName} <br>
Last Name : ${reservation.lastName} <br>
Gender: ${reservation.gender}<br>
Meals: 
<ul>
<c:forEach var="meal" items="${reservation.food}">
<li>${meal}</li>
</c:forEach>
</ul>
Leaving From : ${reservation.cityFrom} <br>
Going To : ${reservation.cityTo}
</body>
</html>

输出:

Spring MVC表单下拉列表
Spring MVC表单下拉列表
Spring MVC表单下拉列表
Spring MVC表单下拉列表

Setter注入和集合示例