SpringBoot WEB开发


@Override
public void addResourceHandlers(ResourceHandlerRegistry registry) {
    if (!this.resourceProperties.isAddMappings()) {
        logger.debug("Default resource handling disabled");
        return;
    }
    addResourceHandler(registry, "/webjars/**", "classpath:/META-INF/resources/webjars/");
    addResourceHandler(registry, this.mvcProperties.getStaticPathPattern(), (registration) -> {
        registration.addResourceLocations(this.resourceProperties.getStaticLocations());
        if (this.servletContext != null) {
            ServletContextResource resource = new ServletContextResource(this.servletContext, SERVLET_LOCATION);
            registration.addResourceLocations(resource);
        }
    });
}
private void addResourceHandler(ResourceHandlerRegistry registry, String pattern, String... locations) {
    addResourceHandler(registry, pattern, (registration) -> registration.addResourceLocations(locations));
}
private void addResourceHandler(ResourceHandlerRegistry registry, String pattern, Consumer customizer) {
if (registry.hasMappingForPattern(pattern)) {
    return;
}
ResourceHandlerRegistration registration = registry.addResourceHandler(pattern);
customizer.accept(registration);
registration.setCachePeriod(getSeconds(this.resourceProperties.getCache().getPeriod()));
registration.setCacheControl(this.resourceProperties.getCache().getCachecontrol().toHttpCacheControl());
registration.setUseLastModified(this.resourceProperties.getCache().isUseLastModified());
customizeResourceHandlerRegistration(registration);
}

二、导入静态资源

1.通过Maven导入

什么是webjars？

WebJars是被打包成JAR文件 (Java Archive)形式的客户端web资源库（例如：jQuery、Bootstrap等）。即WebJars是库，是各种web资源库，打包成jar文件形式。

webjars官网：WebJars - Documentation

具体参考：SpringBoot之使用WebJars - 简书 (jianshu.com)

复制并添加到pom.xml中

启动项目，在地址栏输入jquery文件路径localhost:8080/webjars/github-com-jquery-jquery/3.6.0/jquery.js

2. publi、static、/**、resources

🔥可以被识别到的目录

测试

结果：

3.优先级

resource > static > public

三、首页

⭐WelcomePageHandlerMapping


/**
 * An {@link AbstractUrlHandlerMapping} for an application's welcome page. Supports both
 * static and templated files. If both a static and templated index page are available,
 * the static page is preferred.
 *
 * @author Andy Wilkinson
 * @author Bruce Brouwer
 */
final class WelcomePageHandlerMapping extends AbstractUrlHandlerMapping {
 
	private static final Log logger = LogFactory.getLog(WelcomePageHandlerMapping.class);
 
	private static final List MEDIA_TYPES_ALL = Collections.singletonList(MediaType.ALL);
 
	WelcomePageHandlerMapping(TemplateAvailabilityProviders templateAvailabilityProviders,
			ApplicationContext applicationContext, Resource welcomePage, String staticPathPattern) {
		if (welcomePage != null && "/**".equals(staticPathPattern)) {
			logger.info("Adding welcome page: " + welcomePage);
			setRootViewName("forward:index.html");
		}
		else if (welcomeTemplateExists(templateAvailabilityProviders, applicationContext)) {
			logger.info("Adding welcome page template: index");
			setRootViewName("index");
		}
	}
 
	private boolean welcomeTemplateExists(TemplateAvailabilityProviders templateAvailabilityProviders,
			ApplicationContext applicationContext) {
		return templateAvailabilityProviders.getProvider("index", applicationContext) != null;
	}
 
	private void setRootViewName(String viewName) {
		ParameterizableViewController controller = new ParameterizableViewController();
		controller.setViewName(viewName);
		setRootHandler(controller);
		setOrder(2);
	}
 
	@Override
	public Object getHandlerInternal(HttpServletRequest request) throws Exception {
		for (MediaType mediaType : getAcceptedMediaTypes(request)) {
			if (mediaType.includes(MediaType.TEXT_HTML)) {
				return super.getHandlerInternal(request);
			}
		}
		return null;
	}
 
	private List getAcceptedMediaTypes(HttpServletRequest request) {
		String acceptHeader = request.getHeader(HttpHeaders.ACCEPT);
		if (StringUtils.hasText(acceptHeader)) {
			return MediaType.parseMediaTypes(acceptHeader);
		}
		return MEDIA_TYPES_ALL;
	}
 
}

测试：

注意：在templates目录下的所有页面，只能通过controller来跳转

四、Thymeleaf模板引擎

1.什么是模板引擎？

模板引擎(用于Web开发)是为了使用户界面与业务数据(内容)分离而产生的，它可以生成特定格式的文档，用于网站的模板引擎就会生成一个标准的HTML文档。

前端交给我们的页面，是html页面。如果是我们以前开发，我们需要把他们转成jsp页面

jsp好处就是当我们查出一些数据转发到JSP页面以后，我们可以用jsp轻松实现数据的显示，及交互等。

jsp支持非常强大的功能，包括能写Java代码，但是SpringBoot项目是以jar的方式，不是war，且使用了Tomcat，因此默认是不支持jsp的。

SpringBoot推荐使用模板引擎：

其实jsp就是一个模板引擎，还有用的比较多的freemarker，包括SpringBoot给我们推荐的Thymeleaf，模板引擎有非常多，但再多的模板引擎，他们的思想都是一样的，如图：

2.模板引擎的作用

模板引擎的作用就是我们来写一个页面模板，比如有值的，动态的，表达式。

而这些值是我们在后台封装一些数据。然后把这个模板和这个数据交给模板引擎，模板引擎按照数据把表达式解析、填充到我们指定的位置，然后把这个数据最终生成一个我们想要的内容给我们写出去。

Thymeleaf旨在提供⼀个优雅的、⾼度可维护的创建模板的⽅式。为了实现这⼀⽬标，Thymeleaf建⽴在⾃然模板的概念上，将其逻辑注⼊到模板⽂件中，不会影响模板设计原型。这改善了设计的沟通，弥合了设计和开发团队之间的差距。 做到了页面和展示的分离。

3.引入thymeleaf依赖

http://13. Build Systems (spring.io)

spring-boot/pom.xml at v2.1.6.RELEASE · spring-projects/spring-boot · GitHub


<dependency>
    <groupId>org.thymeleafgroupId>
    <artifactId>thymeleaf-spring5artifactId>
dependency>
<dependency>
    <groupId>org.thymeleaf.extrasgroupId>
    <artifactId>thymeleaf-extras-java8timeartifactId>
dependency>

确认成功导入

ThymeleafProperties 源码


@ConfigurationProperties(prefix = "spring.thymeleaf")
public class ThymeleafProperties {
 
	private static final Charset DEFAULT_ENCODING = StandardCharsets.UTF_8; //默认编码
 
	public static final String DEFAULT_PREFIX = "classpath:/templates/"; //前缀
 
	public static final String DEFAULT_SUFFIX = ".html"; //后缀必须以.html结尾
 
	/**
	 * Whether to check that the template exists before rendering it.
	 */
	private boolean checkTemplate = true;
 
	/**
	 * Whether to check that the templates location exists.
	 */
	private boolean checkTemplateLocation = true;
 
	/**
	 * Prefix that gets prepended to view names when building a URL.
	 */
	private String prefix = DEFAULT_PREFIX;
 
	/**
	 * Suffix that gets appended to view names when building a URL.
	 */
	private String suffix = DEFAULT_SUFFIX;
 
	/**
	 * Template mode to be applied to templates. See also Thymeleaf's TemplateMode enum.
	 */
	private String mode = "HTML";
 
	/**
	 * Template files encoding.
	 */
	private Charset encoding = DEFAULT_ENCODING;
 
	/**
	 * Whether to enable template caching.
	 */
	private boolean cache = true;
 
	/**
	 * Order of the template resolver in the chain. By default, the template resolver is
	 * first in the chain. Order start at 1 and should only be set if you have defined
	 * additional "TemplateResolver" beans.
	 */
	private Integer templateResolverOrder;
 
	/**
	 * Comma-separated list of view names (patterns allowed) that can be resolved.
	 */
	private String[] viewNames;
 
	/**
	 * Comma-separated list of view names (patterns allowed) that should be excluded from
	 * resolution.
	 */
	private String[] excludedViewNames;
 
	/**
	 * Enable the SpringEL compiler in SpringEL expressions.
	 */
	private boolean enableSpringElCompiler;
 
	/**
	 * Whether hidden form inputs acting as markers for checkboxes should be rendered
	 * before the checkbox element itself.
	 */
	private boolean renderHiddenMarkersBeforeCheckboxes = false;
 
	/**
	 * Whether to enable Thymeleaf view resolution for Web frameworks.
	 */
	private boolean enabled = true;
 
	private final Servlet servlet = new Servlet();
 
	private final Reactive reactive = new Reactive();
 
	public boolean isEnabled() {
		return this.enabled;
	}
 
	public void setEnabled(boolean enabled) {
		this.enabled = enabled;
	}
 
	public boolean isCheckTemplate() {
		return this.checkTemplate;
	}
 
	public void setCheckTemplate(boolean checkTemplate) {
		this.checkTemplate = checkTemplate;
	}
 
	public boolean isCheckTemplateLocation() {
		return this.checkTemplateLocation;
	}
 
	public void setCheckTemplateLocation(boolean checkTemplateLocation) {
		this.checkTemplateLocation = checkTemplateLocation;
	}
 
	public String getPrefix() {
		return this.prefix;
	}
 
	public void setPrefix(String prefix) {
		this.prefix = prefix;
	}
 
	public String getSuffix() {
		return this.suffix;
	}
 
	public void setSuffix(String suffix) {
		this.suffix = suffix;
	}
 
	public String getMode() {
		return this.mode;
	}
 
	public void setMode(String mode) {
		this.mode = mode;
	}
 
	public Charset getEncoding() {
		return this.encoding;
	}
 
	public void setEncoding(Charset encoding) {
		this.encoding = encoding;
	}
 
	public boolean isCache() {
		return this.cache;
	}
 
	public void setCache(boolean cache) {
		this.cache = cache;
	}
 
	public Integer getTemplateResolverOrder() {
		return this.templateResolverOrder;
	}
 
	public void setTemplateResolverOrder(Integer templateResolverOrder) {
		this.templateResolverOrder = templateResolverOrder;
	}
 
	public String[] getExcludedViewNames() {
		return this.excludedViewNames;
	}
 
	public void setExcludedViewNames(String[] excludedViewNames) {
		this.excludedViewNames = excludedViewNames;
	}
 
	public String[] getViewNames() {
		return this.viewNames;
	}
 
	public void setViewNames(String[] viewNames) {
		this.viewNames = viewNames;
	}
 
	public boolean isEnableSpringElCompiler() {
		return this.enableSpringElCompiler;
	}
 
	public void setEnableSpringElCompiler(boolean enableSpringElCompiler) {
		this.enableSpringElCompiler = enableSpringElCompiler;
	}
 
	public boolean isRenderHiddenMarkersBeforeCheckboxes() {
		return this.renderHiddenMarkersBeforeCheckboxes;
	}
 
	public void setRenderHiddenMarkersBeforeCheckboxes(boolean renderHiddenMarkersBeforeCheckboxes) {
		this.renderHiddenMarkersBeforeCheckboxes = renderHiddenMarkersBeforeCheckboxes;
	}
 
	public Reactive getReactive() {
		return this.reactive;
	}
 
	public Servlet getServlet() {
		return this.servlet;
	}
 
	public static class Servlet {
 
		/**
		 * Content-Type value written to HTTP responses.
		 */
		private MimeType contentType = MimeType.valueOf("text/html");
 
		/**
		 * Whether Thymeleaf should start writing partial output as soon as possible or
		 * buffer until template processing is finished.
		 */
		private boolean producePartialOutputWhileProcessing = true;
 
		public MimeType getContentType() {
			return this.contentType;
		}
 
		public void setContentType(MimeType contentType) {
			this.contentType = contentType;
		}
 
		public boolean isProducePartialOutputWhileProcessing() {
			return this.producePartialOutputWhileProcessing;
		}
 
		public void setProducePartialOutputWhileProcessing(boolean producePartialOutputWhileProcessing) {
			this.producePartialOutputWhileProcessing = producePartialOutputWhileProcessing;
		}
 
	}
 
	public static class Reactive {
 
		/**
		 * Maximum size of data buffers used for writing to the response. Templates will
		 * execute in CHUNKED mode by default if this is set.
		 */
		private DataSize maxChunkSize = DataSize.ofBytes(0);
 
		/**
		 * Media types supported by the view technology.
		 */
		private List mediaTypes;
 
		/**
		 * Comma-separated list of view names (patterns allowed) that should be executed
		 * in FULL mode even if a max chunk size is set.
		 */
		private String[] fullModeViewNames;
 
		/**
		 * Comma-separated list of view names (patterns allowed) that should be the only
		 * ones executed in CHUNKED mode when a max chunk size is set.
		 */
		private String[] chunkedModeViewNames;
 
		public List getMediaTypes() {
			return this.mediaTypes;
		}
 
		public void setMediaTypes(List mediaTypes) {
			this.mediaTypes = mediaTypes;
		}
 
		public DataSize getMaxChunkSize() {
			return this.maxChunkSize;
		}
 
		public void setMaxChunkSize(DataSize maxChunkSize) {
			this.maxChunkSize = maxChunkSize;
		}
 
		public String[] getFullModeViewNames() {
			return this.fullModeViewNames;
		}
 
		public void setFullModeViewNames(String[] fullModeViewNames) {
			this.fullModeViewNames = fullModeViewNames;
		}
 
		public String[] getChunkedModeViewNames() {
			return this.chunkedModeViewNames;
		}
 
		public void setChunkedModeViewNames(String[] chunkedModeViewNames) {
			this.chunkedModeViewNames = chunkedModeViewNames;
		}
 
	}
 
}

3.使用

导入对应的依赖，将html放在templates目录下即可


//在templates目录下的所有页面，只能通过controller来跳转
//需要模板引擎的支持：thymeleaf
@Controller
public class IndexController {
    @RequestMapping("/test")
    public String index(){
        return "test";
    }
}

运行结果

五、Thymeleaf语法

1.thymeleaf 中文文档

关于我们 · Using Thymeleaf 译文 (gitbooks.io)

2.thymeleaf 属性优先级

3.Thymeleaf标准表达式语法(Thymeleaf Standard Expression syntax)。

我们已经见过了两种用这种语法表达的合理的属性值：消息和变量表达式：


<p th:utext="#{home.welcome}">Welcome to our grocery store!p>
 
<p>Today is: <span th:text="${today}">25 August 2022span>p>

但是表达式的种类远不止这些，而且关于我们已知的这两种还有一些更有趣的细节需要了解。首先，让我们快速的看一下标准表达式的功能。

简单表达式 Simple Expressions:
- 变量表达式 Variable Expressions： ${...}
- 选中变量表达式 Selection Variable Expressions: *{...}
- 消息表达式 Message Expressions: #{...}
- 连接URL表达式 Link URL Expressions: @{...}
- 片段表达式 Fragment Expressions: ~{...}
常量 Literals
- 文本常量 Text literals: 'one text', 'Another one!',…
- 数字常量 Number literals: 0, 34, 3.0, 12.3,…
- 布尔常量 Boolean literals: true, false
- 空常量 Null literal: null
- 常符号 Literal tokens: one, sometext, main,…
文本操作 Text operations:
- 字符串连接 String concatenation: +
- 常量替换 Literal substitutions: |The name is ${name}|
算数操作 Arithmetic operations:
- Binary operators: +, -, *, /, %
- Minus sign (unary operator): -
布尔操作 Boolean operations:
- 布尔操作符 Binary operators: and, or
- 布尔否定一元操作符Boolean negation (unary operator): !, not
比较和相等 Comparisons and equality:
- 比较符 Comparators: >, <, >=, <= (gt, lt, ge, le)
- 相等符 Equality operators: ==, != (eq, ne)
条件操作符 Conditional operators:
- If-then: (if) ? (then)
- If-then-else: (if) ? (then) : (else)
- 默认值 Default: (value) ?: (defaultvalue)
特殊符号 Special tokens:
- 无操作符 No-Operation: _

这些功能可以自由的组合和嵌套:

'User is of type ' + (${user.isAdmin()} ? 'Administrator' : (${user.type} ?: 'Unknown'))

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原文地址：https://blog.csdn.net/m0_52982868/article/details/126498988