详解注解配置整合Spring MVC+Thymeleaf整合实例

柔情只为你懂 2022-07-10 23:43 270阅读 0赞

必须jar包：Spring相关jar包、attoparser-2.0.2.RELEASE.jar、thymeleaf-3.0.3.RELEASE.jar、thymeleaf-spring4-3.0.3.RELEASE.jar(该包为thymeleaf3.03与spring4的整合包，若版本不同，可能会因版本差异出现异常，最后下载对应版本)、unbescape-1.1.4.RELEASE.jar，Thymeleaf所需jar包皆已打包到个人博客资源，有需要的可以去下载，其它的如hibernate-validator等请自行下载(因主题是Thymeleaf)，也可到http://search.maven.org/查找自己对应版本的jar包。

该实例改自《Spring实战 第四版》，改因是一些版本的差异问题，Thymeleaf3.0版本之后改动了不少地方

Thymeleaf模板视图解析器配置步骤：模板解析器->模板引擎->视图解析器，注释掉的代码为个人JSP、Tiles视图解析器的测试代码，与本例无关。

Spitter.java(需加入hibernate-validator-x.x.x.Final.jar、jboss-logging-x.x.x.jar、slf4j-api-1.x.x.jar、commons-lang3-3.x.jar)

package spittr.vo;
    
    import org.apache.commons.lang3.builder.EqualsBuilder;
    import org.apache.commons.lang3.builder.HashCodeBuilder;
    import org.hibernate.validator.constraints.Length;
    import org.hibernate.validator.constraints.NotEmpty;
    
    public class Spitter {
    	private Long id;
    	@NotEmpty
    	@Length(min=5,max=15,message="{javax.validation.constraints.Size.message}")
    	private String username;
    	@NotEmpty
    	@Length(min=5,max=15,message="{javax.validation.constraints.Size.message}")
    	private String password;
    	@NotEmpty
    	@Length(min=2,max=30,message="{javax.validation.constraints.Size.message}")
    	private String firstName;
    	@NotEmpty
    	@Length(min=2,max=30,message="{javax.validation.constraints.Size.message}")
    	private String lastName;
    
    	public Spitter() {
    	}
    
    	public Spitter(String username, String password, String firstName, String lastName) {
    		this.username = username;
    		this.password = password;
    		this.firstName = firstName;
    		this.lastName = lastName;
    	}
    
    	public Spitter(Long id, String username, String password, String firstName, String lastName) {
    		this.id = id;
    		this.username = username;
    		this.password = password;
    		this.firstName = firstName;
    		this.lastName = lastName;
    	}
    
    	public Long getId() {
    		return id;
    	}
    
    	public void setId(Long id) {
    		this.id = id;
    	}
    
    	public String getUsername() {
    		return username;
    	}
    
    	public void setUsername(String username) {
    		this.username = username;
    	}
    
    	public String getPassword() {
    		return password;
    	}
    
    	public void setPassword(String password) {
    		this.password = password;
    	}
    
    	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;
    	}
    
    	@Override
    	public int hashCode() {
    		return HashCodeBuilder.reflectionHashCode(this, "firstName", "lastName", "username", "password");
    	}
    
    	@Override
    	public boolean equals(Object obj) {
    		return EqualsBuilder.reflectionEquals(this, obj, "firstName", "lastName", "username", "password");
    	}
    
    }

SpittrWebAppInitializer.java

package spittr.config;
    
    import org.springframework.web.servlet.support.AbstractAnnotationConfigDispatcherServletInitializer;
    
    /*
     * 在Servlet3.0以上的环境中，容器会在类路径中查找实现javax.servlet.ServletContainerInitializer接口的类，如果发现则用它来配置
     * Servlet容器，Spring提供了这个接口的实现名为SpringServletContainerInitializer,这个类反过来又会查找实现了
     * WebApplicationInitializer的类并把配置任务交给它们来完成,AbstractAnnotationConfigDispatcherServletInitializer的祖先类已
     * 对该接口进行了实现
     */
    public class SpittrWebAppInitializer extends AbstractAnnotationConfigDispatcherServletInitializer {
    	/**
    	 * 该方法用于配置ContextLoaderListener创建的应用上下文的bean，相当于web.xml配置中的
    	 * <listener>org.springframework.web.ContextLoaderListener</listener> 差异：
    	 * 注解配置需要添加的是配置类<br>
    	 * 文件配置ContextLoaderListener在创建时自动查找WEB-INF下的applicationContext.xml文件，当文件不止1个时需通过设置
    	 * 上下文参数(context-param)配置contextConfigLocation的值
    	 * 
    	 * @return 带有@Configuration注解的类(这些类将会用来配置ContextLoaderListener创建的应用上下文的bean)
    	 */
    	@Override
    	protected Class<?>[] getRootConfigClasses() {
    		return new Class<?>[] { RootConfig.class };
    	}
    
    	/**
    	 * 该方法用于配置DispatcherServlet所需bean，配置类一般用于生成控制层的bean(因Controller中一般包含对参数的设置及数据的返回)
    	 * 相当于web.xml对Spring
    	 * MVC的配置…<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>…<br>
    	 * 配置类如WebConfig.class相当于DispatcherServlet中contetConfigLocation参数对应的配置文件
    	 * 
    	 * @return 带有@Configuration注解的类(这些类将会用来配置DispatcherServlet应用上下文中的bean)
    	 */
    	@Override
    	protected Class<?>[] getServletConfigClasses() {
    		return new Class<?>[] { WebConfig.class };
    	}
    
    	/**
    	 * DispatcherServlet默认映射路径
    	 */
    	@Override
    	protected String[] getServletMappings() {
    		return new String[] { ("/") };
    	}
    
    }

WebConfig.java

package spittr.config;
    
    import org.springframework.context.annotation.Bean;
    import org.springframework.context.annotation.ComponentScan;
    import org.springframework.context.annotation.Configuration;
    import org.springframework.web.context.ContextLoader;
    import org.springframework.web.context.WebApplicationContext;
    import org.springframework.web.servlet.ViewResolver;
    import org.springframework.web.servlet.config.annotation.DefaultServletHandlerConfigurer;
    import org.springframework.web.servlet.config.annotation.EnableWebMvc;
    import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;
    import org.thymeleaf.TemplateEngine;
    import org.thymeleaf.spring4.SpringTemplateEngine;
    import org.thymeleaf.spring4.view.ThymeleafViewResolver;
    import org.thymeleaf.templatemode.TemplateMode;
    import org.thymeleaf.templateresolver.ITemplateResolver;
    import org.thymeleaf.templateresolver.ServletContextTemplateResolver;
    
    /**
     * 
     * @author Wilson
     *         该类用于扫描生成Web组件所需的bean,通过实现WebMvcConfigurerAdapter对SpringMVC的配置根据自己需求进行自定义
     */
    @Configuration
    @EnableWebMvc // 相当于<mvc:annotation-driver/>，启用注解驱动的Spring MVC,使@RequestParam、@RequestMapping等注解可以被识别
    @ComponentScan(basePackages = "spittr.web")
    public class WebConfig extends WebMvcConfigurerAdapter {
    	// JSP视图解析器
    	/*
    	 * @Bean public ViewResolver internalViewResolver(){
    	 * InternalResourceViewResolver viewResolver = new
    	 * InternalResourceViewResolver("/WEB-INF/views/", ".jsp");
    	 * viewResolver.setExposeContextBeansAsAttributes(true); return
    	 * viewResolver; }
    	 */
    
    	@Override
    	public void configureDefaultServletHandling(DefaultServletHandlerConfigurer configurer) {
    		configurer.enable();
    	}
    
    	/*@Bean
    	public MessageSource messageSource() {
    		ResourceBundleMessageSource message = new ResourceBundleMessageSource();
    		message.setBasename("welcome");
    		message.setUseCodeAsDefaultMessage(true);
    		return message;
    	}*/
    
    	// tiles文件解析器
    	/*
    	 * @Bean public TilesConfigurer tilesConfigurer() { TilesConfigurer tiles =
    	 * new TilesConfigurer(); tiles.setDefinitions(new String[] {
    	 * "/WEB-INF/layout/tiles.xml" }); // 指定tiles文件位置
    	 * tiles.setCheckRefresh(true); return tiles; }
    	 * 
    	 * // Apache Tiles视图解析器
    	 * 
    	 * @Bean public ViewResolver tilesViewResolver() { return new
    	 * TilesViewResolver(); }
    	 */
    
    	@Bean // 配置生成模板解析器
    	public ITemplateResolver templateResolver() {
    		WebApplicationContext webApplicationContext = ContextLoader.getCurrentWebApplicationContext();
    		// ServletContextTemplateResolver需要一个ServletContext作为构造参数，可通过WebApplicationContext 的方法获得
    		ServletContextTemplateResolver templateResolver = new ServletContextTemplateResolver(
    				webApplicationContext.getServletContext());
    		templateResolver.setPrefix("/WEB-INF/thymeleaf/");
    		templateResolver.setSuffix(".html");
    		// templateResolver.setCharacterEncoding("UTF-8");
    		// 设置模板模式,也可用字符串"HTML"代替,此处不建议使用HTML5,原因看下图源码
    		templateResolver.setTemplateMode(TemplateMode.HTML);
    		return templateResolver;
    	}
    
    	@Bean // 生成模板引擎并为模板引擎注入模板解析器
    	public TemplateEngine templateEngine(ITemplateResolver templateResolver) {
    		SpringTemplateEngine templateEngine = new SpringTemplateEngine();
    		templateEngine.setTemplateResolver(templateResolver);
    		return templateEngine;
    	}
    
    	@Bean // 生成视图解析器并未解析器注入模板引擎
    	public ViewResolver viewResolver(TemplateEngine templateEngine) {
    		ThymeleafViewResolver viewResolver = new ThymeleafViewResolver();
    		viewResolver.setContentType("text/html; charset=utf-8");
    		viewResolver.setTemplateEngine(templateEngine);
    		return viewResolver;
    	}
    }WebApplicationContext 的方法获得
    		ServletContextTemplateResolver templateResolver = new ServletContextTemplateResolver(
    				webApplicationContext.getServletContext());
    		templateResolver.setPrefix("/WEB-INF/thymeleaf/");
    		templateResolver.setSuffix(".html");
    		// templateResolver.setCharacterEncoding("UTF-8");
    		// 设置模板模式,也可用字符串"HTML"代替,此处不建议使用HTML5,原因看下图源码
    		templateResolver.setTemplateMode(TemplateMode.HTML);
    		return templateResolver;
    	}
    
    	@Bean // 生成模板引擎并为模板引擎注入模板解析器
    	public TemplateEngine templateEngine(ITemplateResolver templateResolver) {
    		SpringTemplateEngine templateEngine = new SpringTemplateEngine();
    		templateEngine.setTemplateResolver(templateResolver);
    		return templateEngine;
    	}
    
    	@Bean // 生成视图解析器并未解析器注入模板引擎
    	public ViewResolver viewResolver(TemplateEngine templateEngine) {
    		ThymeleafViewResolver viewResolver = new ThymeleafViewResolver();
    		viewResolver.setContentType("text/html; charset=utf-8");
    		viewResolver.setTemplateEngine(templateEngine);
    		return viewResolver;
    	}
    }

图一：![Center][]

实现了该接口(WebMvcConfigurer)的@EnableWebMvc注解配置类将被回调和获得定制默认配置的能力(个人觉得译为“计划”不太合适),  
继承WebMvcConfigurerAdapter的类会被作为提供所有接口方法的根实现的类，而WebMvcConfigurerAdapter中所有方法都为空，所以可以根据  
个人需求进行覆写。若没有配置视图解析器，Spring会默认使用BeanNameViewResolver，这个视图解析器会查找ID与视图名匹配的bean，  
并且查找的bean要实现View接口。但问题是虽然我进行了视图解析器的配置，但我不知道它是如何作为默认解析器的，因WebMvcConfigurerAdapter中  
没有任何关于默认解析器的配置操作，个人臆测是扫描到WebMvcConfigurer的实现类中包含ViewResolver的bean所以进行优先装配，但还没发现源码。  
图二：![Center 1][]  
  
TemplateMode中的HTML5将在3.1版本中被移除，所以若有设置templateResolver.setTemplateMode(TemplateMode.HTML5)  
及templateResolver.setTemplateMode("HTML5")习惯的都有必要改一下了

HomeController.java

package spittr.web;
    
    import javax.validation.Valid;
    
    import org.springframework.stereotype.Controller;
    import org.springframework.ui.Model;
    import org.springframework.validation.BindingResult;
    import org.springframework.web.bind.annotation.PathVariable;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RequestMethod;
    
    import spittr.vo.Spitter;
    
    @Controller
    public class HomeController {
    	@RequestMapping("/")
    	public String home() {
    		return "home";
    	}
    
    	@RequestMapping("/toRegister")
    	public String toRegister(Model model) {
    		model.addAttribute(new Spitter());	//若要返回JSON数据可添加@ResponseBody注解，返回类型改为类，如return new Spitter();
    		return "registerForm";
    	}
    
    	@RequestMapping(value = "/register", method = RequestMethod.POST)
    	public String register(@Valid Spitter spitter, BindingResult bindResult, Model model) {
    		if (bindResult.hasErrors()) {
    			System.out.println("错误数目:" + bindResult.getErrorCount());
    			model.addAttribute(spitter);
    			return "registerForm";
    		}
    		return "redirect:/cal/" + spitter.getId();
    	}
    
    	/*@RequestMapping(path = { "/cal/{spitterId}" }, method = RequestMethod.GET)
    	public String pathId(@PathVariable int spitterId, Model model) {
    		model.addAttribute("num", spitterId);
    		return "count";
    	}*/
    }

home.html

<html xmlns="http://www.w3.org/1999/xhtml"
          xmlns:th="http://www.thymeleaf.org">
    <head>
    <title>Insert title here</title>
    </head>
    <body>
    	Welcome to Thymeleaf
    	<br/>
    	<a th:href="@{/toRegister}">register</a>
    </body>
    </html>

"@\{\}"用来计算相对于当前URL的路径，相当于Spring<s:url>与JSTL<c:url>

registerForm.html

<html xmlns="http://www.w3.org/1999/xhtml"
    	xmlns:th="http://www.thymeleaf.org">
    <head>
    <meta charset="utf-8" http-equiv="charset" content="utf-8"></meta>
    <title>Insert title here</title>
    <style type="text/css">
    label.error {
    	color: red;
    }
    
    input.error {
    	background-color: #ffcccc;
    }
    </style>
    </head>
    <body>
    	 <form id="form-1" method="post" th:object="${spitter}" th:action="register">
    		<label th:class="${#fields.hasErrors('id')}?'error'">id:</label>
    		<input th:field="*{id}" th:class="${#fields.hasErrors('id')}?'error'" placeholder="id" type="text"></input>
    		<span th:if="${#fields.hasErrors('id')}">
    			<span th:text="${#fields.errors('id')}"></span>
    		</span>
    		<br>
    		<label th:class="${#fields.hasErrors('username')}?'error'">username:</label>
    		<input th:class="${#fields.hasErrors('username')}?'error'" placeholder="username" type="text"
    			 th:field="*{username}"></input>
    		<span th:if="${#fields.hasErrors('username')}">
    			<span th:text="${#fields.errors('username')}"></span>
    		</span>
    		<br>
    		<label th:class="${#fields.hasErrors('password')}?'error'">password:</label>
    		<input th:class="${#fields.hasErrors('password')}?'error'" th:field="*{password}" placeholder="password"
    			 type="text"></input>
    		<span th:if="${#fields.hasErrors('password')}">
    			<span th:text="${#fields.errors('password')}"></span>
    		</span>
    		<br>
    		<label th:class="${#fields.hasErrors('firstName')}?'error'">firstName:</label>
    		<input  th:class="${#fields.hasErrors('firstName')}?'error'" th:field="*{firstName}" type="text" 
    			placeholder="firstName"/></input>
    		<span th:if="${#fields.hasErrors('firstName')}">
    			<span th:text="${#fields.errors('firstName')}"></span>
    		</span>
    		<br>
    		<label th:class="${#fields.hasErrors('lastName')}?'error'">lastName:</label>
    		<input th:class="${#fields.hasErrors('lastName')}?'error'" placeholder="lastName" th:field="*{lastName}"
    			 type="text"></input>
    		<span th:if="${#fields.hasErrors('lastName')}">
    			<span th:text="${#fields.errors('lastName')}"></span>
    		</span>
    		<br>
    		<input type="submit"></input>
    	</form> 
    </body>
    </html>

$\{\}为变量表达式，一般是对象图导航语言(OGNL)，在使用Spring时则是SpEL表达式，在该例中th:object的设置会解析key为spitter的model属性，所以在跳转到注册页前需  
把spitter添加到model中(如上红字代码)，当提交时时spitter中属性进行了重新填充所以即使错误回调表单也不会为空。  
\*\{\}为选择表达式，变量表达式是基于整个SpEL上下文计算的，而选择表达式是基于某一个选中对象计算的，本例中选中对象是th:object属性所设置的对象  
th:class根据给定的表达式计算渲染为哪个class属性。  
\#fields为表单中的所有域，可通过该属性对表单中的各种属性进行相应的操作：  
如：<span th:if="$\{\#fields.hasErrors('lastName')\}">  
<span th:text="$\{\#fields.errors('lastName')\}"></span>  
</span>   
判断lastName是否不符合格式(Spitter.java中进行了格式设置)，若是则输出lastName格式错误的原因，也可用通配符代替"lastName"，如  
<div class="errors" th:if="$\{\#fields.hasErrors('\*')\}">  
<ul>  
<li th:each="err:$\{\#fields.errors('\*')\}>  
<span th:text="$\{err\}"></span>  
</li>  
</ul>  
</div>迭代输出错误信息  
更多thymeleaf标签属性：[http://www.cnblogs.com/hjwublog/p/5051732.html][http_www.cnblogs.com_hjwublog_p_5051732.html]  
由于html文件是xhtml标注，所以不加</\*\*\*>都会有提示但不碍事  
包目录（红色框内为本例所用文件）

![Center 2][]![Center 3][]

![Center 4][]

![Center 5][]

把hibernate-validator中的ValidationMessages资源文件拷贝到根目录下即可显示错误信息。

[Center]: /images/20220711/ddbc37263e4743fd8ac09e7a16e5d7a8.png
[Center 1]: /images/20220711/50df343142c642108ad7c030847a1a4c.png
[http_www.cnblogs.com_hjwublog_p_5051732.html]: http://www.cnblogs.com/hjwublog/p/5051732.html
[Center 2]: https://img-blog.csdn.net/20170115155442375?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQvejI4MTI2MzA4/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/Center
[Center 3]: /images/20220711/973ef00928c244a28ebe67e4a5a6b7ab.png
[Center 4]: /images/20220711/33f81fd30c474ceabd83da38a5712fe9.png
[Center 5]: /images/20220711/73eca7eaf74d4f87b5ca2a98f4ad153d.png