在這篇文章中，我們將學(xué)習(xí)如何使用Spring表單標(biāo)簽，表單驗(yàn)證使用 JSR303 的驗(yàn)證注解，hibernate-validators，提供了使用MessageSource和訪問靜態(tài)資源(如CSS，JavaScript，圖片)國際化支持我們的視圖，使用ResourceHandlerRegistry，全部采用基于注解的配置。

我們將創(chuàng)建一個(gè)包含一個(gè)學(xué)生注冊表格的簡單應(yīng)用，用戶輸入表單提交驗(yàn)證通過 JSR303 的驗(yàn)證注釋驗(yàn)證，通過覆蓋屬性文件可使用國際驗(yàn)證消息的默認(rèn)消息，還訪問靜態(tài)資源(如應(yīng)用引導(dǎo)CSS到網(wǎng)頁中)。

請注意，JSR303是一種規(guī)范，hibernate-validator是我們在這篇文章中使用的一種實(shí)現(xiàn)，它也提供了幾個(gè)不包含在規(guī)范中自己的驗(yàn)證注釋。

使用以下技術(shù)：

Spring 4.0.6.RELEASE
validation-api 1.1.0.Final
hibernate-validator 5.1.2.Final
Bootstrap v3.1.0
Maven 3
JDK 1.6
Tomcat 7.0.54
Eclipse JUNO Service Release 2

我們現(xiàn)在開始！

第1步：創(chuàng)建目錄結(jié)構(gòu)

以下將是最終的項(xiàng)目結(jié)構(gòu)(這里需要先創(chuàng)建一個(gè)Maven工程為：Spring4MVCFormValidationExample)：

現(xiàn)在讓我們在每個(gè)細(xì)節(jié)上述結(jié)構(gòu)中提到的內(nèi)容來做一點(diǎn)解釋。

第2步：更新pom.xml，包括所需的依賴關(guān)系

<?xml version="1.0"?>
<project xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"
	xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">

	<modelVersion>4.0.0</modelVersion>
	<groupId>com.yiibai.springmvc</groupId>
	<artifactId>Spring4MVCFormValidationExample</artifactId>
	<packaging>war</packaging>
	<version>1.0.0</version>
	<name>Spring4MVCFormValidationExample</name>

	<properties>
		<springframework.version>4.0.6.RELEASE</springframework.version>
		<hibernate.validator.version>5.1.2.Final</hibernate.validator.version>
		<javax.validation.version>1.1.0.Final</javax.validation.version>
	</properties>

	<dependencies>
		<!-- Spring dependencies -->
		<dependency>
			<groupId>org.springframework</groupId>
			<artifactId>spring-core</artifactId>
			<version>${springframework.version}</version>
		</dependency>
		<dependency>
			<groupId>org.springframework</groupId>
			<artifactId>spring-web</artifactId>
			<version>${springframework.version}</version>
		</dependency>
		<dependency>
			<groupId>org.springframework</groupId>
			<artifactId>spring-webmvc</artifactId>
			<version>${springframework.version}</version>
		</dependency>

		<!-- jsr303 validation dependencies-->
		<dependency>
			<groupId>javax.validation</groupId>
			<artifactId>validation-api</artifactId>
			<version>${javax.validation.version}</version>
		</dependency>
		<dependency>
			<groupId>org.hibernate</groupId>
			<artifactId>hibernate-validator</artifactId>
			<version>${hibernate.validator.version}</version>
		</dependency>

		<!-- Servlet dependencies -->
		<dependency>
			<groupId>javax.servlet</groupId>
			<artifactId>javax.servlet-api</artifactId>
			<version>3.1.0</version>
		</dependency>
		<dependency>
			<groupId>javax.servlet.jsp</groupId>
			<artifactId>javax.servlet.jsp-api</artifactId>
			<version>2.3.1</version>
		</dependency>
		<dependency>
		    <groupId>javax.servlet</groupId>
		    <artifactId>jstl</artifactId>
		    <version>1.2</version>
		</dependency>
	</dependencies>

	<build>
		<pluginManagement>
			<plugins>
				<plugin>
					<groupId>org.apache.maven.plugins</groupId>
					<artifactId>maven-war-plugin</artifactId>
					<version>2.4</version>
					<configuration>
						<warSourceDirectory>src/main/webapp</warSourceDirectory>
						<warName>Spring4MVCFormValidationExample</warName>
						<failOnMissingWebXml>false</failOnMissingWebXml>
					</configuration>
				</plugin>
			</plugins>
		</pluginManagement>
		<finalName>Spring4MVCFormValidationExample</finalName>
	</build>
</project>

首先要注意這里是 maven-war-plugin 插件聲明。由于我們使用的是全注解配置，我們甚至不包括在 web.xml 中，所以我們需要配置這個(gè)插件，以避免Maven構(gòu)建war包失敗。在驗(yàn)證部分 validation-api 代表規(guī)范，而hibernate-validator是本規(guī)范的一個(gè)實(shí)現(xiàn)。hibernate-validator還提供了一些它自己的注解(@Email，@NotEmpty等)不屬于規(guī)范的一部分。

伴隨著這一點(diǎn)，我們也包括JSP/Servlet/Jstl 的依賴關(guān)系，也將需要為使用 servlet API和JSTL視圖在我們的代碼中。在一般情況下，容器可能已經(jīng)包含了這些庫，從而在pom.xml中我們可以設(shè)置范圍作為“provided”。

此外，這里還單獨(dú)下載了 bootstrap.css ，為了演示在基于注解的配置如何使用資源處理。

第3步：創(chuàng)建POJO/域?qū)ο?

訪問的對象將充當(dāng)一個(gè)輔助bean的形式保存用戶提供簽證申請表提交的數(shù)據(jù)。我們將注釋，以驗(yàn)證屬性(使用驗(yàn)證注釋)。

com.yiibai.springmvc.model.Student

package com.yiibai.springmvc.model;

import java.io.Serializable;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;

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

import org.hibernate.validator.constraints.Email;
import org.hibernate.validator.constraints.NotEmpty;
import org.springframework.format.annotation.DateTimeFormat;

public class Student implements Serializable {

	@Size(min=3, max=30)
	private String firstName;

	@Size(min=3, max=30)
	private String lastName;

	@NotEmpty
	private String sex;

	@DateTimeFormat(pattern="yyyy-MM-dd")
	@Past @NotNull
	private Date dob;

	@Email @NotEmpty
	private String email;

	@NotEmpty
	private String section;

	@NotEmpty
	private String country;

	private boolean firstAttempt;

	@NotEmpty
	private List<String> subjects = new ArrayList<String>();

	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 getSex() {
		return sex;
	}

	public void setSex(String sex) {
		this.sex = sex;
	}

	public Date getDob() {
		return dob;
	}

	public void setDob(Date dob) {
		this.dob = dob;
	}

	public String getEmail() {
		return email;
	}

	public void setEmail(String email) {
		this.email = email;
	}

	public String getSection() {
		return section;
	}

	public void setSection(String section) {
		this.section = section;
	}

	public String getCountry() {
		return country;
	}

	public void setCountry(String country) {
		this.country = country;
	}

	public boolean isFirstAttempt() {
		return firstAttempt;
	}

	public void setFirstAttempt(boolean firstAttempt) {
		this.firstAttempt = firstAttempt;
	}

	public List<String> getSubjects() {
		return subjects;
	}

	public void setSubjects(List<String> subjects) {
		this.subjects = subjects;
	}

	@Override
	public String toString() {
		return "Student [firstName=" + firstName + ", lastName=" + lastName
				+ ", sex=" + sex + ", dob=" + dob + ", email=" + email
				+ ", section=" + section + ", country=" + country
				+ ", firstAttempt=" + firstAttempt + ", subjects=" + subjects
				+ "]";
	}

}

在上面的代碼中：@Size, @Past & @NotNull 是標(biāo)準(zhǔn)的標(biāo)注，而@NotEmpty＆@Emailare是規(guī)范的一部分。

第4步：添加控制器

控制器加入將有助于處理GET和POST請求。

com.yiibai.springmvc.controller.HelloWorldController

package com.yiibai.springmvc.controller;

import java.util.ArrayList;
import java.util.List;

import javax.validation.Valid;

import org.springframework.stereotype.Controller;
import org.springframework.ui.ModelMap;
import org.springframework.validation.BindingResult;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;

import com.websystique.springmvc.model.Student;

@Controller
@RequestMapping("/")
public class HelloWorldController {

	/*
	 * This method will serve as default GET handler.
	 *
	 */
	@RequestMapping(method = RequestMethod.GET)
	public String newRegistration(ModelMap model) {
		Student student = new Student();
		model.addAttribute("student", student);
		return "enroll";
	}

	/*
	 * This method will be called on form submission, handling POST request
	 * It also validates the user input
	 */
	@RequestMapping(method = RequestMethod.POST)
	public String saveRegistration(@Valid Student student, BindingResult result, ModelMap model){

		if(result.hasErrors()) {
		        return "enroll";
		}

		model.addAttribute("success", "Dear "+ student.getFirstName()+" , your Registration completed successfully");
		return "success";
	}

	/*
	 * Method used to populate the Section list in view.
	 * Note that here you can call external systems to provide real data.
	 */
	@ModelAttribute("sections")
	public List<String> initializeSections() {

		List<String> sections = new ArrayList<String>();
		sections.add("Graduate");
		sections.add("Post Graduate");
		sections.add("Research");
 		return sections;
	}

	/*
	 * Method used to populate the country list in view.
	 * Note that here you can call external systems to provide real data.
	 */
	@ModelAttribute("countries")
	public List<String> initializeCountries() {

		List<String> countries = new ArrayList<String>();
		countries.add("USA");
		countries.add("CHINA");
		countries.add("FRANCE");
		countries.add("GERMANY");
		countries.add("ITALY");
		countries.add("OTHER");
 		return countries;
	}

	/*
	 * Method used to populate the subjects list in view.
	 * Note that here you can call external systems to provide real data.
	 */
	@ModelAttribute("subjects")
	public List<String> initializeSubjects() {

		List<String> subjects = new ArrayList<String>();
		subjects.add("Physics");
		subjects.add("Chemistry");
		subjects.add("Life Science");
		subjects.add("Political Science");
		subjects.add("Computer Science");
		subjects.add("Mathmatics");
 		return subjects;
	}

}

@Controller表明這個(gè)類是一個(gè)控制器在處理具有模式映射的@RequestMapping請求。這里使用 ‘/’, 它被作為默認(rèn)的控制器。方法newRegistration是相當(dāng)簡單的，注解為@ RequestMethod.GET服務(wù)默認(rèn)是GET請求，使用模型對象，以服務(wù)為形式的數(shù)據(jù)，并呈現(xiàn)包含空白表單的網(wǎng)頁。

方法initializeSections, initializeCountries & initializeSubjects是簡單地創(chuàng)建請求級別的對象，其值在視圖/JSP中將被使用。

方法saveRegistration 標(biāo)注有@ RequestMethod.POST，并將處理表單提交POST請求。注意本方法的參數(shù)和它們的順序。

@Valid要求spring來驗(yàn)證相關(guān)的對象(學(xué)生)。 BindingResult包含此驗(yàn)證，并可能在此驗(yàn)證過程中發(fā)生(產(chǎn)生)任何錯(cuò)誤的結(jié)果。請注意，BindingResult一定要在之后立即生效對象，否則spring將無法驗(yàn)證并且將一個(gè)異常拋出。

注意，在校驗(yàn)失敗后，默認(rèn)/廣義錯(cuò)誤消息顯示在屏幕上這可能不是所期望的。相反，可以重寫此行為提供具體到每個(gè)字段中國際化消息。為了做到這一點(diǎn)，我們需要配置 MessageSource 在應(yīng)用程序配置類，并提供包含我們下一步將配置實(shí)際的信息屬性文件。

第5步：添加配置類

com.yiibai.springmvc.configuration.HelloWorldConfiguration

package com.yiibai.springmvc.configuration;

import org.springframework.context.MessageSource;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.support.ResourceBundleMessageSource;
import org.springframework.web.servlet.ViewResolver;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
import org.springframework.web.servlet.config.annotation.ResourceHandlerRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;
import org.springframework.web.servlet.view.InternalResourceViewResolver;
import org.springframework.web.servlet.view.JstlView;

@Configuration
@EnableWebMvc
@ComponentScan(basePackages = "com.yiibai.springmvc")
public class HelloWorldConfiguration extends WebMvcConfigurerAdapter {

	/*
	 * Configure View Resolver
	 */
	@Bean
	public ViewResolver viewResolver() {
		InternalResourceViewResolver viewResolver = new InternalResourceViewResolver();
		viewResolver.setViewClass(JstlView.class);
		viewResolver.setPrefix("/WEB-INF/views/");
		viewResolver.setSuffix(".jsp");
		return viewResolver;
	}

	/*
	 * Configure ResourceHandlers to serve static resources like CSS/ Javascript etc...
	 *
	 */
	@Override
	public void addResourceHandlers(ResourceHandlerRegistry registry) {
	    registry.addResourceHandler("/static/**").addResourceLocations("/static/");
	}

	/*
	 * Configure MessageSource to provide internationalized messages
	 *
	 */

	@Bean
	public MessageSource messageSource() {
	    ResourceBundleMessageSource messageSource = new ResourceBundleMessageSource();
	    messageSource.setBasename("messages");
	    return messageSource;
	}

}

@Configuration指示該類包含注解為@Bean生產(chǎn)Bean管理是由Spring容器的一個(gè)或多個(gè) bean 的方法。@EnableWebMvc 等效于 mvc:annotation-driven 在XML文件中。它能夠?yàn)槭褂聾RequestMapping 向特定的方法傳入的請求映射@Controller-annotated類。 @ComponentScan 等效于 context:component-scan base-package="..." 提供具有到哪里查找管理Spring beans/類。

方法 ViewResolver 配置一個(gè) ViewResolver 用來找出真正的視圖。方法 addResourceHandlers 配置 ResourceHandler 靜態(tài)資源。CSS, JavaScript, images 等都是靜態(tài)的資源在你的頁面里。上面的配置表示，所有的資源請求開始/static/，將從webapps文件夾下提供/static/。在這個(gè)例子中，我們把所有的css文件放在 Web應(yīng)用程序的 /static/css 目錄中。注意，此方法在 WebMvcConfigurerAdapter 中定義，因此我們需要擴(kuò)展這個(gè)類來注冊我們的靜態(tài)資源覆蓋此方法。

方法為 messageSource 配置消息包，以支持[國際化]消息屬性文件。請注意方法 baseName 提供的參數(shù)(消息)。Spring 將搜索應(yīng)用程序類路徑中一個(gè)名為messages.properties文件。讓我們添加的文件：

src/main/resources/messages.properties

Size.student.firstName=First Name must be between {2} and {1} characters long
Size.student.lastName=Last Name must be between {2} and {1} characters long
NotEmpty.student.sex=Please specify your gender
NotNull.student.dob=Date of birth can not be blank
Past.student.dob=Date of birth must be in the past
Email.student.email=Please provide a valid Email address
NotEmpty.student.email=Email can not be blank
NotEmpty.student.country=Please select your country
NotEmpty.student.section=Please select your section
NotEmpty.student.subjects=Please select at least one subject
typeMismatch=Invalid format

請注意，上述消息按照特定的模式

{ValidationAnnotationClass}.{modelObject}.{fieldName}

此外，根據(jù)具體的注釋(如@Size)，也可以用傳遞參數(shù)給這些消息：{0},{1},..{i}

以XML格式上述結(jié)構(gòu)將是

<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:context="http://www.springframework.org/schema/context"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:mvc="http://www.springframework.org/schema/mvc"
    xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.0.xsd
    http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-4.0.xsd
    http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd">
 
    <context:component-scan base-package="com.yiibai.springmvc" />
    <mvc:annotation-driven/>

    <mvc:resources mapping="/static/**" location="/static/" />
    <mvc:default-servlet-handler />


    <bean id="messageSource" class="org.springframework.context.support.ResourceBundleMessageSource">
        <property name="basename">
            <value>messages</value>
        </property>
    </bean>


    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="prefix">
            <value>/WEB-INF/views/</value>
        </property>
        <property name="suffix">
            <value>.jsp</value>
        </property>
    </bean>
 
</beans>

第6步：添加視圖(簡單的JSP頁面)

我們將添加兩個(gè)簡單的JSP頁面。第一個(gè)將包含一個(gè)表單，從用戶接收輸入，而第二個(gè)在當(dāng)表單輸入驗(yàn)證成功時(shí)會(huì)顯示成功消息給用戶。

下面是代碼，用于包括靜態(tài)資源(在我們的例子中使用 bootstrap.css)

<link href="<c:url value='/static/css/bootstrap.css' />" rel="stylesheet"></link>

注意靜態(tài)資源路徑。既然我們已經(jīng)在前面的步驟配置資源處理程序 /static/**, css文件將搜索 /static/文件夾。

完整的JSP文件如下所示：

WEB-INF/views/enroll.jsp

<%@ page language="java" contentType="text/html; charset=utf-8"
    pageEncoding="utf-8"%>
<%@ taglib prefix="form" uri="http://www.springframework.org/tags/form"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<html>
<head>
	<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
	<title>Student Enrollment Form</title>
	<link href="<c:url value='/static/css/bootstrap.css' />" rel="stylesheet"></link>
	<link href="<c:url value='/static/css/custom.css' />" rel="stylesheet"></link>
</head>

<body>
 	<div class="form-container">
 	<h1>Enrollment Form</h1>
	<form:form method="POST" modelAttribute="student" class="form-horizontal">
		<div class="row">
			<div class="form-group col-md-12">
				<label class="col-md-3 control-lable" for="firstName">First Name</label>
				<div class="col-md-7">
					<form:input type="text" path="firstName" id="firstName" class="form-control input-sm"/>
					<div class="has-error">
						<form:errors path="firstName" class="help-inline"/>
					</div>
				</div>
			</div>
		</div>

		<div class="row">
			<div class="form-group col-md-12">
				<label class="col-md-3 control-lable" for="lastName">Last Name</label>
				<div class="col-md-7">
					<form:input type="text" path="lastName" id="lastName" class="form-control input-sm"/>
					<div class="has-error">
						<form:errors path="lastName" class="help-inline"/>
					</div>
				</div>
			</div>
		</div>

		<div class="row">
			<div class="form-group col-md-12">
				<label class="col-md-3 control-lable" for="sex">Sex</label>
				<div class="col-md-7" class="form-control input-sm">
					<form:radiobutton path="sex" value="M" />Male 
	    			<form:radiobutton path="sex" value="F" />Female
					<div class="has-error">
						<form:errors path="sex" class="help-inline"/>
					</div>
				</div>
			</div>
		</div>

		<div class="row">
			<div class="form-group col-md-12">
				<label class="col-md-3 control-lable" for="dob">Date of birth</label>
				<div class="col-md-7">
					<form:input type="text" path="dob" id="dob" class="form-control input-sm"/>
					<div class="has-error">
						<form:errors path="dob" class="help-inline"/>
					</div>
				</div>
			</div>
		</div>

		<div class="row">
			<div class="form-group col-md-12">
				<label class="col-md-3 control-lable" for="email">Email</label>
				<div class="col-md-7">
					<form:input type="text" path="email" id="email" class="form-control input-sm"/>
					<div class="has-error">
						<form:errors path="email" class="help-inline"/>
					</div>
				</div>
			</div>
		</div>


		<div class="row">
			<div class="form-group col-md-12">
				<label class="col-md-3 control-lable" for="section">Section</label>
				<div class="col-md-7" class="form-control input-sm">
					<form:radiobuttons path="section" items="${sections}" />
					<div class="has-error">
						<form:errors path="section" class="help-inline"/>
					</div>
				</div>
			</div>
		</div>


		<div class="row">
			<div class="form-group col-md-12">
				<label class="col-md-3 control-lable" for="country">Country</label>
				<div class="col-md-7">
					<form:select path="country" id="country" class="form-control input-sm">
				        <form:option value="">Select Country</form:option>
			    	    <form:options items="${countries}" />
				    </form:select>
					<div class="has-error">
						<form:errors path="country" class="help-inline"/>
					</div>
				</div>
			</div>
		</div>

		<div class="row">
			<div class="form-group col-md-12">
				<label class="col-md-3 control-lable" for="firstAttempt">First Attempt ?</label>
				<div class="col-md-1">
					<form:checkbox path="firstAttempt" class="form-control input-sm"/>
					<div class="has-error">
						<form:errors path="firstAttempt" class="help-inline"/>
					</div>
				</div>
			</div>
		</div>
	

		<div class="row">
			<div class="form-group col-md-12">
				<label class="col-md-3 control-lable" for="subjects">Subjects</label>
				<div class="col-md-7">
					<form:select path="subjects" items="${subjects}" multiple="true" class="form-control input-sm"/>
					<div class="has-error">
						<form:errors path="subjects" class="help-inline"/>
					</div>
				</div>
			</div>
		</div>

		<div class="row">
			<div class="form-actions floatRight">
				<input type="submit" value="Register" class="btn btn-primary btn-sm">
			</div>
		</div>
	</form:form>
	</div>
</body>
</html>

WEB-INF/views/success.jsp

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
    pageEncoding="ISO-8859-1"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<html>
<head>
	<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
	<title>Student Enrollment Detail Confirmation</title>
	<link href="<c:url value='/static/css/custom.css' />" rel="stylesheet"></link>
</head>
<body>
	<div class="success">
		Confirmation message : ${success}
		<br>
		We have also sent you a confirmation mail to your email address : ${student.email}.
	</div>
</body>
</html>

第7步：添加初始化器類

com.yiibai.springmvc.configuration.HelloWorldInitializer

package com.yiibai.springmvc.configuration;

import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.ServletRegistration;

import org.springframework.web.WebApplicationInitializer;
import org.springframework.web.context.support.AnnotationConfigWebApplicationContext;
import org.springframework.web.servlet.DispatcherServlet;

public class HelloWorldInitializer implements WebApplicationInitializer {

	public void onStartup(ServletContext container) throws ServletException {

		AnnotationConfigWebApplicationContext ctx = new AnnotationConfigWebApplicationContext();
		ctx.register(HelloWorldConfiguration.class);
		ctx.setServletContext(container);

		ServletRegistration.Dynamic servlet = container.addServlet(
				"dispatcher", new DispatcherServlet(ctx));

		servlet.setLoadOnStartup(1);
		servlet.addMapping("/");
	}

}

內(nèi)容上面類似之前教程的 web.xml 文件內(nèi)容，因?yàn)槲覀兪褂玫氖乔岸丝刂破鞯腄ispatcherServlet，分配映射(URL模式的XML)和而不是提供給Spring配置文件(spring-servlet.xml)的路徑，在這里，我們使用注冊配置類。

更新：請注意，上面的類可以寫成更加簡潔[和這是最佳方法]，通過擴(kuò)展 AbstractAnnotationConfigDispatcherServletInitializer 基類,如下所示：

package com.websystique.springmvc.configuration;

import org.springframework.web.servlet.support.AbstractAnnotationConfigDispatcherServletInitializer;

public class HelloWorldInitializer extends AbstractAnnotationConfigDispatcherServletInitializer {

	@Override
	protected Class<?>[] getRootConfigClasses() {
		return new Class[] { HelloWorldConfiguration.class };
	}
 
	@Override
	protected Class<?>[] getServletConfigClasses() {
		return null;
	}
 
	@Override
	protected String[] getServletMappings() {
		return new String[] { "/" };
	}

}

第8步：構(gòu)建和部署應(yīng)用程序

有一點(diǎn)要記住，如：WebApplicationInitializer，Spring 基于Java 配置API是依賴Servlet3.0容器的。所以一定要確保你沒有使用 Servlet 聲明任何在 web.xml 小于3.0。對于我們的情況，我們要從應(yīng)用程序中刪除 web.xml 文件。

現(xiàn)在構(gòu)建war 或通過Maven 命令行(mvn clean install)。部署 war 到Servlet3.0容器。

運(yùn)行應(yīng)用程序，訪問URL：http://localhost:8080/Spring4MVCFormValidationExample

得到的初始頁面如下圖所示：