## 1、簡介
使用SpringBoot；
**1）、創建SpringBoot應用，選中我們需要的模塊；**
**2）、SpringBoot已經默認將這些場景配置好了，只需要在配置文件中指定少量配置就可以運行起來**
**3）、自己編寫業務代碼；**
**自動配置原理？**
這個場景SpringBoot幫我們配置了什麼？能不能修改？能修改哪些配置？能不能擴展？xxx
```
xxxxAutoConfiguration：幫我們給容器中自動配置組件；
xxxxProperties:配置類來封裝配置文件的內容；
```
## 2、SpringBoot對靜態資源的映射規則；
```java
@ConfigurationProperties(prefix = "spring.resources", ignoreUnknownFields = false)
public class ResourceProperties implements ResourceLoaderAware {
//可以設置和靜態資源有關的參數，緩存時間等
```
```java
WebMvcAuotConfiguration：
@Override
public void addResourceHandlers(ResourceHandlerRegistry registry) {
if (!this.resourceProperties.isAddMappings()) {
logger.debug("Default resource handling disabled");
return;
}
Integer cachePeriod = this.resourceProperties.getCachePeriod();
if (!registry.hasMappingForPattern("/webjars/**")) {
customizeResourceHandlerRegistration(
registry.addResourceHandler("/webjars/**")
.addResourceLocations(
"classpath:/META-INF/resources/webjars/")
.setCachePeriod(cachePeriod));
}
String staticPathPattern = this.mvcProperties.getStaticPathPattern();
//靜態資源文件夾映射
if (!registry.hasMappingForPattern(staticPathPattern)) {
customizeResourceHandlerRegistration(
registry.addResourceHandler(staticPathPattern)
.addResourceLocations(
this.resourceProperties.getStaticLocations())
.setCachePeriod(cachePeriod));
}
}
//配置歡迎頁映射
@Bean
public WelcomePageHandlerMapping welcomePageHandlerMapping(
ResourceProperties resourceProperties) {
return new WelcomePageHandlerMapping(resourceProperties.getWelcomePage(),
this.mvcProperties.getStaticPathPattern());
}
//配置喜歡的圖標
@Configuration
@ConditionalOnProperty(value = "spring.mvc.favicon.enabled", matchIfMissing = true)
public static class FaviconConfiguration {
private final ResourceProperties resourceProperties;
public FaviconConfiguration(ResourceProperties resourceProperties) {
this.resourceProperties = resourceProperties;
}
@Bean
public SimpleUrlHandlerMapping faviconHandlerMapping() {
SimpleUrlHandlerMapping mapping = new SimpleUrlHandlerMapping();
mapping.setOrder(Ordered.HIGHEST_PRECEDENCE + 1);
//所有 **/favicon.ico
mapping.setUrlMap(Collections.singletonMap("**/favicon.ico",
faviconRequestHandler()));
return mapping;
}
@Bean
public ResourceHttpRequestHandler faviconRequestHandler() {
ResourceHttpRequestHandler requestHandler = new ResourceHttpRequestHandler();
requestHandler
.setLocations(this.resourceProperties.getFaviconLocations());
return requestHandler;
}
}
```
==1）、所有 /webjars/** ，都去 classpath:/META-INF/resources/webjars/ 找資源；==
webjars：以jar包的方式引入靜態資源；
http://www.webjars.org/
localhost:8080/webjars/jquery/3.3.1/jquery.js
```xml
<!--引入jquery-webjar-->在訪問的時候只需要寫webjars下面資源的名稱即可
<dependency>
<groupId>org.webjars</groupId>
<artifactId>jquery</artifactId>
<version>3.3.1</version>
</dependency>
```
==2）、"/**" 訪問當前項目的任何資源，都去（靜態資源的文件夾）找映射==
```
"classpath:/META-INF/resources/",
"classpath:/resources/",
"classpath:/static/",
"classpath:/public/"
"/"：當前項目的根路徑
```
localhost:8080/abc === 去靜態資源文件夾裏面找abc
==3）、歡迎頁； 靜態資源文件夾下的所有index.html頁面；被"/**"映射；==
localhost:8080/ 找index頁面
==4）、所有的 **/favicon.ico 都是在靜態資源文件下找；==
## 3、模板引擎
JSP、Velocity、Freemarker、Thymeleaf
SpringBoot推薦的Thymeleaf；
語法更簡單，功能更強大；
### 1、引入thymeleaf；
```xml
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-thymeleaf</artifactId>
2.1.6
</dependency>
切換thymeleaf版本
<properties>
<thymeleaf.version>3.0.9.RELEASE</thymeleaf.version>
<!-- 佈局功能的支持程序 thymeleaf3主程序 layout2以上版本 -->
<!-- thymeleaf2 layout1-->
<thymeleaf-layout-dialect.version>2.2.2</thymeleaf-layout-dialect.version>
</properties>
```
### 2、Thymeleaf使用
```java
@ConfigurationProperties(prefix = "spring.thymeleaf")
public class ThymeleafProperties {
private static final Charset DEFAULT_ENCODING = Charset.forName("UTF-8");
private static final MimeType DEFAULT_CONTENT_TYPE = MimeType.valueOf("text/html");
public static final String DEFAULT_PREFIX = "classpath:/templates/";
public static final String DEFAULT_SUFFIX = ".html";
//
```
只要我們把HTML頁面放在classpath:/templates/，thymeleaf就能自動渲染；
使用：
1、導入thymeleaf的名稱空間
```xml
<html lang="en" xmlns:th="http://www.thymeleaf.org">
```
2、使用thymeleaf語法；
```html
<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.thymeleaf.org">
<head>
<meta charset="UTF-8">
<title>Title</title>
</head>
<body>
<h1>成功！</h1>
<!--th:text 將div裏面的文本內容設置爲 -->
<div th:text="${hello}">這是顯示歡迎信息</div>
</body>
</html>