SpringBoot---web开发

Posted 咖啡加糖

tags:

篇首语:本文由小常识网(cha138.com)小编为大家整理,主要介绍了SpringBoot---web开发相关的知识,希望对你有一定的参考价值。


1、简介
使用SpringBoot;
1)、创建SpringBoot应用,选中我们需要的模块;
2)、SpringBoot已经默认将这些场景配置好了,只需要在配置文件中指定少量配置就可以运行起来
3)、自己编写业务代码;
自动配置原理?
这个场景SpringBoot帮我们配置了什么?能不能修改?能修改哪些配置?能不能扩展?xxx

xxxxAutoConfiguration:帮我们给容器中自动配置组件;
xxxxProperties:配置类来封装配置文件的内容;

 2、SpringBoot对静态资源的映射规则

@ConfigurationProperties(prefix = "spring.resources", ignoreUnknownFields = false)
public class ResourceProperties implements ResourceLoaderAware {
//可以设置和静态资源有关的参数,缓存时间等
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();
//静态资源文件夹映射
if (!registry.hasMappingForPattern(staticPathPattern)) {
customizeResourceHandlerRegistration(
registry.addResourceHandler(staticPathPattern)
.addResourceLocations(
this.resourceProperties.getStaticLocations())
.setCachePeriod(cachePeriod));
}
}
//配置欢迎页映射
@Bean
public WelcomePageHandlerMapping welcomePageHandlerMapping(
ResourceProperties resourceProperties) {
return new WelcomePageHandlerMapping(resourceProperties.getWelcomePage(),
this.mvcProperties.getStaticPathPattern());
}
//配置喜欢的图标
@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/ 找资源;
webjars:以jar包的方式引入静态资源;
http://www.webjars.org/

 

 

 

localhost:8080/webjars/jquery/3.3.1/jquery.js

<!‐‐引入jquery‐webjar‐‐>在访问的时候只需要写webjars下面资源的名称即可
<dependency>
<groupId>org.webjars</groupId>
<artifactId>jquery</artifactId>
<version>3.3.1</version>
</dependency>

2)、"/**" 访问当前项目的任何资源,都去(静态资源的文件夹)找映射

"classpath:/META‐INF/resources/",
"classpath:/resources/",
"classpath:/static/",
"classpath:/public/"
"/":当前项目的根路径

localhost:8080/abc === 去静态资源文件夹里面找abc
3)、欢迎页; 静态资源文件夹下的所有index.html页面;被"/**"映射;
localhost:8080/ 找index页面
4)、所有的 **/favicon.ico 都是在静态资源文件下找;

3、模板引擎
JSP、Velocity、Freemarker、Thymeleaf

 

 

 

SpringBoot推荐的Thymeleaf;
语法更简单,功能更强大;

1、引入thymeleaf;

<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring‐boot‐starter‐thymeleaf</artifactId>
2.1.6
</dependency>
切换thymeleaf版本
<properties>
<thymeleaf.version>3.0.9.RELEASE</thymeleaf.version>
<!‐‐ 布局功能的支持程序 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

@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";

只要我们把HTML页面放在classpath:/templates/,thymeleaf就能自动渲染;
使用:
1、导入thymeleaf的名称空间

<html lang="en" xmlns:th="http://www.thymeleaf.org">

2、使用thymeleaf语法;

<!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 将div里面的文本内容设置为 ‐‐>
<div th:text="${hello}">这是显示欢迎信息</div>
</body>
</html>

3、语法规则
1)、th:text;改变当前元素里面的文本内容;
th:任意html属性;来替换原生属性的值

 

 

 2)、表达式?

Simple expressions:(表达式语法)
Variable Expressions: ${...}:获取变量值;OGNL;
1)、获取对象的属性、调用方法
2)、使用内置的基本对象:
#ctx : the context object.
#vars: the context variables.
#locale : the context locale.
#request : (only in Web Contexts) the HttpServletRequest object.
#response : (only in Web Contexts) the HttpServletResponse object.
#session : (only in Web Contexts) the HttpSession object.
#servletContext : (only in Web Contexts) the ServletContext object.
${session.foo}
3)、内置的一些工具对象:
#execInfo : information about the template being processed.
#messages : methods for obtaining externalized messages inside variables expressions, in the
same way as they would be obtained using #{…} syntax.
#uris : methods for escaping parts of URLs/URIs
#conversions : methods for executing the configured conversion service (if any).
#dates : methods for java.util.Date objects: formatting, component extraction, etc.
#calendars : analogous to #dates , but for java.util.Calendar objects.
#numbers : methods for formatting numeric objects.
#strings : methods for String objects: contains, startsWith, prepending/appending, etc.
#objects : methods for objects in general.
#bools : methods for boolean evaluation.
#arrays : methods for arrays.
#lists : methods for lists.
#sets : methods for sets.
#maps : methods for maps.
#aggregates : methods for creating aggregates on arrays or collections.
#ids : methods for dealing with id attributes that might be repeated (for example, as a
result of an iteration).
Selection Variable Expressions: *{...}:选择表达式:和${}在功能上是一样;
补充:配合 th:object="${session.user}:
<div th:object="${session.user}">
<p>Name: <span th:text="*{firstName}">Sebastian</span>.</p>
<p>Surname: <span th:text="*{lastName}">Pepper</span>.</p>
<p>Nationality: <span th:text="*{nationality}">Saturn</span>.</p>
</div>
Message Expressions: #{...}:获取国际化内容
Link URL Expressions: @{...}:定义URL;
@{/order/process(execId=${execId},execType=\'FAST\')}
Fragment Expressions: ~{...}:片段引用表达式
<div th:insert="~{commons :: main}">...</div>
Literals(字面量)
Text literals: \'one text\' , \'Another one!\' ,…
Number literals: 0 , 34 , 3.0 , 12.3 ,…
Boolean literals: true , false
Null literal: null
Literal tokens: one , sometext , main ,…
Text operations:(文本操作)
String concatenation: +
Literal substitutions: |The name is ${name}|
Arithmetic operations:(数学运算)
Binary operators: + , ‐ , * , / , %
Minus sign (unary operator): ‐
Boolean operations:(布尔运算)
Binary operators: and , or
Boolean negation (unary operator): ! , not
Comparisons and equality:(比较运算)
Comparators: > , < , >= , <= ( gt , lt , ge , le )
Equality operators: == , != ( eq , ne )
Conditional operators:条件运算(三元运算符)
If‐then: (if) ? (then)
If‐then‐else: (if) ? (then) : (else)
Default: (value) ?: (defaultvalue)
Special tokens:
No‐Operation: _

4、SpringMVC自动配置

https://docs.spring.io/spring-boot/docs/1.5.10.RELEASE/reference/htmlsingle/#boot-features-developingweb-applications
1. Spring MVC auto-configuration
Spring Boot 自动配置好了SpringMVC
以下是SpringBoot对SpringMVC的默认配置:(WebMvcAutoConfiguration)
Inclusion of ContentNegotiatingViewResolver and BeanNameViewResolver beans.
自动配置了ViewResolver(视图解析器:根据方法的返回值得到视图对象(View),视图对象决定如何
渲染(转发?重定向?))
ContentNegotiatingViewResolver:组合所有的视图解析器的;
如何定制:我们可以自己给容器中添加一个视图解析器;自动的将其组合进来;
Support for serving static resources, including support for WebJars (see below).静态资源文件夹路
径,webjars
Static index.html support. 静态首页访问
Custom Favicon support (see below). favicon.ico
自动注册了 of Converter , GenericConverter , Formatter beans.
Converter:转换器; public String hello(User user):类型转换使用Converter
Formatter 格式化器; 2017.12.17===Date;

@Bean
@ConditionalOnProperty(prefix = "spring.mvc", name = "date‐format")//在文件中配置日期格
式化的规则
public Formatter<Date> dateFormatter() {
return new DateFormatter(this.mvcProperties.getDateFormat());//日期格式化组件
}

自己添加的格式化器转换器,我们只需要放在容器中即可

Support for HttpMessageConverters (see below).
HttpMessageConverter:SpringMVC用来转换Http请求和响应的;User---Json;
HttpMessageConverters 是从容器中确定;获取所有的HttpMessageConverter;
自己给容器中添加HttpMessageConverter,只需要将自己的组件注册容器中
(@Bean,@Component)
Automatic registration of MessageCodesResolver (see below).定义错误代码生成规则
Automatic use of a ConfigurableWebBindingInitializer bean (see below).
我们可以配置一个ConfigurableWebBindingInitializer来替换默认的;(添加到容器)

初始化WebDataBinder;
请求数据=====JavaBean;

org.springframework.boot.autoconfigure.web:web的所有自动场景;
If you want to keep Spring Boot MVC features, and you just want to add additional MVC configuration
(interceptors, formatters, view controllers etc.) you can add your own @Configuration class of type
WebMvcConfigurerAdapter , but without @EnableWebMvc . If you wish to provide custom instances of
RequestMappingHandlerMapping , RequestMappingHandlerAdapter or ExceptionHandlerExceptionResolver
you can declare a WebMvcRegistrationsAdapter instance providing such components.
If you want to take complete control of Spring MVC, you can add your own @Configuration annotated with
@EnableWebMvc

2、扩展SpringMVC

<mvc:view‐controller path="/hello" view‐name="success"/>
<mvc:interceptors>
<mvc:interceptor>
<mvc:mapping path="/hello"/>
<bean></bean>
</mvc:interceptor>
</mvc:interceptors>

编写一个配置类(@Configuration),是WebMvcConfigurerAdapter类型;不能标注@EnableWebMvc;
既保留了所有的自动配置,也能用我们扩展的配置;

//使用WebMvcConfigurerAdapter可以来扩展SpringMVC的功能
@Configuration
public class MyMvcConfig extends WebMvcConfigurerAdapter {
@Override
public void addViewControllers(ViewControllerRegistry registry) {
// super.addViewControllers(registry);
//浏览器发送 /atguigu 请求来到 success
registry.addViewController("/atguigu").setViewName("success");
}
}

原理:
1)、WebMvcAutoConfiguration是SpringMVC的自动配置类
2)、在做其他自动配置时会导入;@Import(EnableWebMvcConfiguration.class)

@Configuration
public static class EnableWebMvcConfiguration extends DelegatingWebMvcConfiguration {
private final WebMvcConfigurerComposite configurers = new WebMvcConfigurerComposite();
//从容器中获取所有的WebMvcConfigurer
@Autowired(required = false)
public void setConfigurers(List<WebMvcConfigurer> configurers) {
if (!CollectionUtils.isEmpty(configurers)) {
this.configurers.addWebMvcConfigurers(configurers);
//一个参考实现;将所有的WebMvcConfigurer相关配置都来一起调用;
@Override
// public void addViewControllers(ViewControllerRegistry registry) {
// for (WebMvcConfigurer delegate : this.delegates) {
// delegate.addViewControllers(registry);
// }
}
}
}

3)、容器中所有的WebMvcConfigurer都会一起起作用;
4)、我们的配置类也会被调用;
效果:SpringMVC的自动配置和我们的扩展配置都会起作用;
3、全面接管SpringMVC;
SpringBoot对SpringMVC的自动配置不需要了,所有都是我们自己配置;所有的SpringMVC的自动配置都失效了
我们需要在配置类中添加@EnableWebMvc即可;

//使用WebMvcConfigurerAdapter可以来扩展SpringMVC的功能
@EnableWebMvc
@Configuration
public class MyMvcConfig extends WebMvcConfigurerAdapter {
@Override
public void addViewControllers(ViewControllerRegistry registry) {
// super.addViewControllers(registry);
//浏览器发送 /atguigu 请求来到 success
registry.addViewController("/atguigu").setViewName("success");
}
}

原理:
为什么@EnableWebMvc自动配置就失效了;

 

1)@EnableWebMvc的核心

@Import(DelegatingWebMvcConfiguration.class)
public @interface EnableWebMvc {

2)、

@Configuration
public class DelegatingWebMvcConfiguration extends WebMvcConfigurationSupport {

3)、

@Configuration
@ConditionalOnWebApplication
@ConditionalOnClass({ Servlet.class, DispatcherServlet.class,
WebMvcConfigurerAdapter.class })
//容器中没有这个组件的时候,这个自动配置类才生效
@ConditionalOnMissingBean(WebMvcConfigurationSupport.class)
@AutoConfigureOrder(Ordered.HIGHEST_PRECEDENCE + 10)
@AutoConfigureAfter({ DispatcherServletAutoConfiguration.class,
ValidationAutoConfiguration.class })
public class WebMvcAutoConfiguration {

4)、@EnableWebMvc将WebMvcConfigurationSupport组件导入进来;
5)、导入的WebMvcConfigurationSupport只是SpringMVC最基本的功能;

5、如何修改SpringBoot的默认配置
模式:
1)、SpringBoot在自动配置很多组件的时候,先看容器中有没有用户自己配置的(@Bean、@Component)如
果有就用用户配置的,如果没有,才自动配置;如果有些组件可以有多个(ViewResolver)将用户配置的和自己默
认的组合起来;
2)、在SpringBoot中会有非常多的xxxConfigurer帮助我们进行扩展配置
3)、在SpringBoot中会有很多的xxxCustomizer帮助我们进行定制配置
6、RestfulCRUD
1)、默认访问首页

//使用WebMvcConfigurerAdapter可以来扩展SpringMVC的功能
//@EnableWebMvc 不要接管SpringMVC
@Configuration
public class MyMvcConfig extends WebMvcConfigurerAdapter {
@Override
public void addViewControllers(ViewControllerRegistry registry) {
// super.addViewControllers(registry);
//浏览器发送 /atguigu 请求来到 success
registry.addViewController("/atguigu").setViewName("success");
}
//所有的WebMvcConfigurerAdapter组件都会一起起作用
@Bean //将组件注册在容器
public WebMvcConfigurerAdapter webMvcConfigurerAdapter(){
WebMvcConfigurerAdapter adapter = new WebMvcConfigurerAdapter() {
@Override
public void addViewControllers(ViewControllerRegistry registry) {
registry.addViewController("/").setViewName("login");
registry.addViewController("/index.html").setViewName("login");
}
};
return adapter;
}
}

2)、国际化
1)、编写国际化配置文件;
2)、使用ResourceBundleMessageSource管理国际化资源文件
3)、在页面使用fmt:message取出国际化内容
步骤:
1)、编写国际化配置文件,抽取页面需要显示的国际化消息

 

 

 2)、SpringBoot自动配置好了管理国际化资源文件的组件;

@ConfigurationProperties(prefix = "spring.messages")
public class MessageSourceAutoConfiguration {
/**
* Comma‐separated list of basenames (essentially a fully‐qualified classpath
* location), each following the ResourceBundle convention with relaxed support for
* slash based locations. If it doesn\'t contain a package qualifier (such as
* "org.mypackage"), it will be resolved from the classpath root.
*/
private String basename = "messages";
//我们的配置文件可以直接放在类路径下叫messages.properties;
@Bean
public MessageSource messageSource() {
ResourceBundleMessageSource messageSource = new ResourceBundleMessageSource();
if (StringUtils.hasText(this.basename)) {
//设置国际化资源文件的基础名(去掉语言国家代码的)
messageSource.setBasenames(StringUtils.commaDelimitedListToStringArray(
StringUtils.trimAllWhitespace(this.basename)));
}
if (this.encoding != null) {
messageSource.setDefaultEncoding(this.encoding.name());
}
messageSource.setFallbackToSystemLocale(this.fallbackToSystemLocale);
messageSource.setCacheSeconds(this.cacheSeconds);
messageSource.setAlwaysUseMessageFormat(this.alwaysUseMessageFormat);
return messageSource;
}

3)、去页面获取国际化的值;

 

 

 

<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.thymeleaf.org">
<head>
<meta http‐equiv="Content‐Type" content="text/html; charset=UTF‐8">
<meta name="viewport" content="width=device‐width, initial‐scale=1, shrink‐to‐
fit=no">
<meta name="description" content="">
<meta name="author" content="">
<title>Signin Template for Bootstrap</title>
<!‐‐ Bootstrap core CSS ‐‐>
<link href="asserts/css/bootstrap.min.css"
th:href="@{/webjars/bootstrap/4.0.0/css/bootstrap.css}" rel="stylesheet">
<!‐‐ Custom styles for this template ‐‐>
<link href="asserts/css/signin.css" th:href="@{/asserts/css/signin.css}"
rel="stylesheet">
</head>
<body class="text‐center">
<form class="form‐signin" action="dashboard.html">
<img class="mb‐4" th:src="@{/asserts/img/bootstrap‐solid.svg}"
src="asserts/img/bootstrap‐solid.svg" alt="" width="72" height="72">
<h1 class="h3 mb‐3 font‐weight‐normal" th:text="#{login.tip}">Please sign
in</h1>
<label class="sr‐only" th:text="#{login.username}">Username</label>
<input type="text" class="form‐control" placeholder="Username" th:placeholder="#
{login.username}" required="" autofocus="">
<label class="sr‐only" th:text="#{login.password}">Password</label>
<input type="password" class="form‐control" placeholder="Password"
th:placeholder="#{login.password}" required="">
<div class="checkbox mb‐3">
<label>
<input type="checkbox" value="remember‐me"/> [[#{login.remember}]]
</label>
</div>
<button class="btn btn‐lg btn‐primary btn‐block" type="submit" th:text="#
{login.btn}">Sign in</button>
<p class="mt‐5 mb‐3 text‐muted">© 2017‐2018</p>
<a class="btn btn‐sm">中文</a>
<a class="btn btn‐sm">English</a>
</form>
</body>
</html>

效果:根据浏览器语言设置的信息切换了国际化;
原理:
国际化Locale(区域信息对象);LocaleResolver(获取区域信息对象);

@Bean
@ConditionalOnMissingBean
@ConditionalOnProperty(prefix = "spring.mvc", name = "locale")
public LocaleResolver localeResolver() {
if (this.mvcProperties
.getLocaleResolver() == WebMvcProperties.LocaleResolver.FIXED) {
return new FixedLocaleResolver(this.mvcProperties.getLocale());
}
AcceptHeaderLocaleResolver localeResolver = new AcceptHeaderLocaleResolver();
localeResolver.setDefaultLocale(this.mvcProperties.getLocale());
return localeResolver;
}
默认的就是根据请求头带来的区域信息获取Locale进行国际化

4)、点击链接切换国际化

/**
* 可以在连接上携带区域信息
*/
public class MyLocaleResolver implements LocaleResolver {
@Override
public Locale resolveLocale(HttpServletRequest request) {
String l = request.getParameter("l");
Locale locale = Locale.getDefault();
if(!StringUtils.isEmpty(l)){
String[] split = l.split("_");
locale = new Locale(split[0],split[1]);
}
return locale;
}
@Override
public void setLocale(HttpServletRequest request, HttpServletResponse response, Locale
locale) {
}
}
@Bean
public LocaleResolver localeResolver(){
return new MyLocaleResolver();
}
}

3)、登陆
开发期间模板引擎页面修改以后,要实时生效

1)、禁用模板引擎的缓存

# 禁用缓存
spring.thymeleaf.cache=false

2)、页面修改完成以后ctrl+f9:重新编译;
登陆错误消息的显示

<p style="color: red" th:text="${msg}" th:if="${not #strings.isEmpty(msg)}"></p>

4)、拦截器进行登陆检查
拦截器

/**
* 登陆检查,
*/
public class LoginHandlerInterceptor implements HandlerInterceptor {
//目标方法执行之前
@Override
public boolean preHandle(HttpServletRequest request, HttpServletResponse response,
Object handler) throws Exception {
Object user = request.getSession().getAttribute("loginUser");
if(user == null){
//未登陆,返回登陆页面
request.setAttribute("msg","没有权限请先登陆");
request.getRequestDispatcher("/index.html").forward(request,response);
return false;
}else{
//已登陆,放行请求
return true;
}
}
@Override
public void postHandle(HttpServletRequest request, HttpServletResponse response, Object
handler, ModelAndView modelAndView) throws Exception {
}
@Override
public void afterCompletion(HttpServletRequest request, HttpServletResponse response,
Object handler, Exception ex) throws Exception {
}
}

注册拦截器

//所有的WebMvcConfigurerAdapter组件都会一起起作用
@Bean //将组件注册在容器
public WebMvcConfigurerAdapter webMvcConfigurerAdapter(){
WebMvcConfigurerAdapter adapter = new WebMvcConfigurerAdapter() {
@Override
public void addViewControllers(ViewControllerRegistry registry) {
registry.addViewController("/").setViewName("login");
registry.addViewController("/index.html").setViewName("login");
registry.addViewController("/main.html").setViewName("dashboard");
}
//注册拦截器
@Override
public void addInterceptors(InterceptorRegistry registry) {
//super.addInterceptors(registry);
//静态资源; *.css , *.js
//SpringBoot已经做好了静态资源映射
registry.addInterceptor(new
LoginHandlerInterceptor()).addPathPatterns("/**")
.excludePathPatterns("/index.html","/","/user/login");
}
};
return adapter;
}

5)、CRUD-员工列表
实验要求:
1)、RestfulCRUD:CRUD满足Rest风格;
URI: /资源名称/资源标识 HTTP请求方式区分对资源CRUD操作

 

 

 2)、实验的请求架构;

 

 

 

3)、员工列表:
thymeleaf公共页面元素抽取

1、抽取公共片段
<div th:fragment="copy">
&copy; 2011 The Good Thymes Virtual Grocery
</div>
2、引入公共片段
<div th:insert="~{footer :: copy}"></div>
~{templatename::selector}:模板名::选择器
~{templatename::fragmentname}:模板名::片段名
3、默认效果:
insert的公共片段在div标签中
如果使用th:insert等属性进行引入,可以不用写~{}:
行内写法可以加上:[[~{}]];[(~{})];

三种引入公共片段的th属性:
th:insert:将公共片段整个插入到声明引入的元素中
th:replace:将声明引入的元素替换为公共片段
th:include:将被引入的片段的内容包含进这个标签中

<footer th:fragment="copy">
&copy; 2011 The Good Thymes Virtual Grocery
</footer>
引入方式
<div th:insert="footer :: copy"></div>
<div th:replace="footer :: copy"></div>
<div th:include="footer :: copy"></div>
效果
<div>
<footer>
&copy; 2011 The Good Thymes Virtual Grocery
</footer>
</div>
<footer>
&copy; 2011 The Good Thymes Virtual Grocery
</footer>
<div>
&copy; 2011 The Good Thymes Virtual Grocery
</div>

引入片段的时候传入参数:

<nav class="col‐md‐2 d‐none d‐md‐block bg‐light sidebar" id="sidebar">
<div class="sidebar‐sticky">
<ul class="nav flex‐column">
<li class="nav‐item">
<a class="nav‐link active"
th:class="${activeUri==\'main.html\'?\'nav‐link active\':\'nav‐link\'}"
href="#" th:href="@{/main.html}">
<svg xmlns="http://www.w3.org/2000/svg" width="24" height="24"
viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke‐width="2" stroke‐
linecap="round" stroke‐linejoin="round" class="feather feather‐home">
<path d="M3 9l9‐7 9 7v11a2 2 0 0 1‐2 2H5a2 2 0 0 1‐2‐2z"></path>
<polyline points="9 22 9 12 15 12 15 22"></polyline>
</svg>
Dashboard <span class="sr‐only">(current)</span>
</a>
</li>
<!‐‐引入侧边栏;传入参数‐‐>
<div th:replace="commons/bar::#sidebar(activeUri=\'emps\')"></div>

6)、CRUD-员工添加
添加页面

<form>
<div class="form‐group">
<label>LastName</label>
<input type="text" class="form‐control" placeholder="zhangsan">
</div>
<div class="form‐group">
<label>Email</label>
<input type="email" class="form‐control" placeholder="zhangsan@atguigu.com">
</div>
<div class="form‐group">
<label>Gender</label><br/>
<div class="form‐check form‐check‐inline">
<input class="form‐check‐input" type="radio" name="gender" value="1">
<label class="form‐check‐label">男</label>
</div>
<div class="form‐check form‐check‐inline">
<input class="form‐check‐input" type="radio" name="gender" value="0">
<label class="form‐check‐label">女</label>
</div>
</div>
<div class="form‐group">
<label>department</label>
<select class="form‐control">
<option>1</option>
<option>2</option>
<option>3</option>
<option>4</option>
<option>5</option>
</select>
</div>
<div class="form‐group">
<label>Birth</label>
<input type="text" class="form‐control" placeholder="zhangsan">
</div>
<button type="submit" class="btn btn‐primary">添加</button>
</form>

提交的数据格式不对:生日:日期;
2017-12-12;2017/12/12;2017.12.12;
日期的格式化;SpringMVC将页面提交的值需要转换为指定的类型;
2017-12-12---Date; 类型转换,格式化;
默认日期是按照/的方式;

7)、CRUD-员工修改
修改添加二合一表单

<!‐‐需要区分是员工修改还是添加;‐‐>
<form th:action="@{/emp}" method="post">
<!‐‐发送put请求修改员工数据‐‐>
<!‐‐
1、SpringMVC中配置HiddenHttpMethodFilter;(SpringBoot自动配置好的)
2、页面创建一个post表单
3、创建一个input项,name="_method";值就是我们指定的请求方式
‐‐>
<input type="hidden" name="_method" value="put" th:if="${emp!=null}"/>
<input type="hidden" name="id" th:if="${emp!=null}" th:value="${emp.id}">
<div class="form‐group">
<label>LastName</label>
<input name="lastName" type="text" class="form‐control" placeholder="zhangsan"
th:value="${emp!=null}?${emp.lastName}">
</div>
<div class="form‐group">
<label>Email</label>
<input name="email" type="email" class="form‐control"
placeholder="zhangsan@atguigu.com" th:value="${emp!=null}?${emp.email}">
</div>
<div class="form‐group">
<label>Gender</label><br/>
<div class="form‐check form‐check‐inline">
<input class="form‐check‐input" type="radio" name="gender" value="1"
th:checked="${emp!=null}?${emp.gender==1}">
<label class="form‐check‐label">男</label>
</div>
<div class="form‐check form‐check‐inline">
<input class="form‐check‐input" type="radio" name="gender" value="0"
th:checked="${emp!=null}?${emp.gender==0}">
<label class="form‐check‐label">女</label>
</div>
</div>
<div class="form‐group">
<label>department</label>
<!‐‐提交的是部门的id‐‐>
<select class="form‐control" name="department.id">
<option th:selected="${emp!=null}?${dept.id == emp.department.id}"
th:value="${dept.id}" th:each="dept:${depts}" th:text="${dept.departmentName}">1</option>
</select>
</div>
<div class="form‐group">
<label>Birth</label>
<input name="birth" type="text" class="form‐control" placeholder="zhangsan"
th:value="${emp!=null}?${#dates.format(emp.birth, \'yyyy‐MM‐dd HH:mm\')}">
</div>
<button type="submit" class="btn btn‐primary" th:text="${emp!=null}?\'修改\':\'添加\'">添加
</button>
</form>

8)、CRUD-员工删除

<tr th:each="emp:${emps}">
<td th:text="${emp.id}"></td>
<td>[[${emp.lastName}]]</td>
<td th:text="${emp.email}"></td>
<td th:text="${emp.gender}==0?\'女\':\'男\'"></td>
<td th:text="${emp.department.departmentName}"></td>
<td th:text="${#dates.format(emp.birth, \'yyyy‐MM‐dd HH:mm\')}"></td>
<td>
<a class="btn btn‐sm btn‐primary" th:href="@{/emp/}+${emp.id}">编辑</a>
<button th:attr="del_uri=@{/emp/}+${emp.id}" class="btn btn‐sm btn‐danger
deleteBtn">删除</button>
</td>
</tr>
<script>
$(".deleteBtn").click(function(){
//删除当前员工的
$("#deleteEmpForm").attr("action",$(this).attr("del_uri")).submit();
return false;
});
</script>

7、错误处理机制
1)、SpringBoot默认的错误处理机制
默认效果:
1)、浏览器,返回一个默认的错误页面

 

 

 浏览器发送请求的请求头:

 

 

 

 

 

 

原理:
可以参照ErrorMvcAutoConfiguration;错误处理的自动配置;
给容器中添加了以下组件
1、DefaultErrorAttributes:

帮我们在页面共享信息;
@Override
public Map<String, Object> getErrorAttributes(RequestAttributes requestAttributes,
boolean includeStackTrace) {
Map<String, Object> errorAttributes = new LinkedHashMap<String, Object>();
errorAttributes.put("timestamp", new Date());
addStatus(errorAttributes, requestAttributes);
addErrorDetails(errorAttributes, requestAttributes, includeStackTrace);
addPath(errorAttributes, requestAttributes);
return errorAttributes;
}

2、BasicErrorController:处理默认/error请求

@Controller
@RequestMapping("${server.error.path:${error.path:/error}}")
public class BasicErrorController extends AbstractErrorController {
@RequestMapping(produces = "text/html")//产生html类型的数据;浏览器发送的请求来到这个方法处理
public ModelAndView errorHtml(HttpServletRequest request,
HttpServletResponse response) {
HttpStatus status = getStatus(request);
Map<String, Object> model = Collections.unmodifiableMap(getErrorAttributes(
request, isIncludeStackTrace(request, MediaType.TEXT_HTML)));
response.setStatus(status.value());
//去哪个页面作为错误页面;包含页面地址和页面内容
ModelAndView modelAndView = resolveErrorView(request, response, status, model);
return (modelAndView == null ? new ModelAndView("error", model) : modelAndView);
}
@RequestMapping
@ResponseBody //产生json数据,其他客户端来到这个方法处理;
public ResponseEntity<Map<String, Object>> error(HttpServletRequest request) {
Map<String, Object> body = getErrorAttributes(request,
isIncludeStackTrace(request, MediaType.ALL));
HttpStatus status = getStatus(request);
return new ResponseEntity<Map<String, Object>>(body, status);
}

3、ErrorPageCustomizer:

@Value("${error.path:/error}")
private String path = "/error"; 系统出现错误以后来到error请求进行处理;(web.xml注册的错误页
面规则)

4、DefaultErrorViewResolver:

@Override
public ModelAndView resolveErrorView(HttpServletRequest request, HttpStatus status,
Map<String, Object> model) {
ModelAndView modelAndView = resolve(String.valueOf(status), model);
if (modelAndView == null && SERIES_VIEWS.containsKey(status.series())) {
modelAndView = resolve(SERIES_VIEWS.get(status.series()), model);
}
return modelAndView;
}
private ModelAndView resolve(String viewName, Map<String, Object> model) {
//默认SpringBoot可以去找到一个页面? error/404
String errorViewName = "error/" + viewName;
//模板引擎可以解析这个页面地址就用模板引擎解析
TemplateAvailabilityProvider provider = this.templateAvailabilityProviders
.getProvider(errorViewName, this.applicationContext);
if (provider != null) {
//模板引擎可用的情况下返回到errorViewName指定的视图地址
return new ModelAndView(errorViewName, model);
}
//模板引擎不可用,就在静态资源文件夹下找errorViewName对应的页面 error/404.html以上是关于SpringBoot---web开发的主要内容,如果未能解决你的问题,请参考以下文章

springBoot:web开发-Servlets, Filters, listeners

springboot---web 应用开发-文件上传

springboot:web综合开发

springboot:web综合开发

SpringBoot :web综合开发

springboot:web综合开发