SpringBoot与Web开发

web开发 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已经配置好了,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帮我们配置了扫码?能不能修改?能不能改哪些配置?能不能扩展?xxx xxxAutoConfiguration:帮我们给容器中自动配置组件; xxxProperties: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又关的的 参数,缓存时间

 1 public void addResourceHandlers(ResourceHandlerRegistry registry) {
 2     if (!this.resourceProperties.isAddMappings()) {
 3         logger.debug("Default resource handling disabled");
 4     } else {
 5         Duration cachePeriod = this.resourceProperties.getCache().getPeriod();
 6         CacheControl cacheControl = this.resourceProperties.getCache().getCachecontrol().toHttpCacheControl();
 7         if (!registry.hasMappingForPattern("/webjars/**")) {
 8             this.customizeResourceHandlerRegistration(registry.addResourceHandler(new String[]{"/webjars/**"}).addResourceLocations(new String[]{"classpath:/META-INF/resources/webjars/"}).setCachePeriod(this.getSeconds(cachePeriod)).setCacheControl(cacheControl));
 9         }
10 
11         String staticPathPattern = this.mvcProperties.getStaticPathPattern();
12         if (!registry.hasMappingForPattern(staticPathPattern)) {
13             this.customizeResourceHandlerRegistration(registry.addResourceHandler(new String[]{staticPathPattern}).addResourceLocations(getResourceLocations(this.resourceProperties.getStaticLocations())).setCachePeriod(this.getSeconds(cachePeriod)).setCacheControl(cacheControl));
14         }
15 
16     }
17 }

//配置欢迎页的映射

 1 @Bean
 2 public WelcomePageHandlerMapping welcomePageHandlerMapping(ApplicationContext applicationContext) {
 3     return new WelcomePageHandlerMapping(new TemplateAvailabilityProviders(applicationContext), applicationContext, this.getWelcomePage(), this.mvcProperties.getStaticPathPattern());
 4 }
 5 
 6 @Configuration
 7 @ConditionalOnProperty(
 8     value = {"spring.mvc.favicon.enabled"},
 9     matchIfMissing = true
10 )
11 public static class FaviconConfiguration implements ResourceLoaderAware {
12     private final ResourceProperties resourceProperties;
13     private ResourceLoader resourceLoader;
14 
15     public FaviconConfiguration(ResourceProperties resourceProperties) {
16         this.resourceProperties = resourceProperties;
17     }
18 
19     public void setResourceLoader(ResourceLoader resourceLoader) {
20         this.resourceLoader = resourceLoader;
21     }
22 
23     @Bean
24     public SimpleUrlHandlerMapping faviconHandlerMapping() {
25         SimpleUrlHandlerMapping mapping = new SimpleUrlHandlerMapping();
26         mapping.setOrder(-2147483647);
27 //所有 **/favicon.ico
28         mapping.setUrlMap(Collections.singletonMap("**/favicon.ico", this.faviconRequestHandler()));
29         return mapping;
30     }
31 
32     @Bean
33     public ResourceHttpRequestHandler faviconRequestHandler() {
34         ResourceHttpRequestHandler requestHandler = new ResourceHttpRequestHandler();
35         requestHandler.setLocations(this.resolveFaviconLocations());
36         return requestHandler;
37     }

//配置喜欢的图标

    private List<Resource> resolveFaviconLocations() {
        String[] staticLocations = WebMvcAutoConfiguration.WebMvcAutoConfigurationAdapter.getResourceLocations(this.resourceProperties.getStaticLocations());
        List<Resource> locations = new ArrayList(staticLocations.length + 1);
        Stream var10000 = Arrays.stream(staticLocations);
        ResourceLoader var10001 = this.resourceLoader;
        this.resourceLoader.getClass();
        var10000.map(var10001::getResource).forEach(locations::add);
        locations.add(new ClassPathResource("/"));
        return Collections.unmodifiableList(locations);
    }
}

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; 参考:http://www.webjars.org/ http://localhost:8080/webjars/jquery/3.3.1-1/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>3.3.1-1</version>
</dependency>

2)、"/**"访问当前项目的任何资源,(静态资源的文件夹)

"classpath:/META-INF/resources/", "classpath:/resources/", "classpath:/static/", "classpath:/public/" "/":当前项目的根路径; localhsot:8080/abc====去静态资源文件夹里面去找abc 3)、欢迎页;静态资源文件夹下面的所有index.html文件;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、模版引擎 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>
</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使用方法 只要我们把html页面放在classpath:/templates/,thymeleaf就能自动渲染; 使用: 1、导入thymleaf的名称空间;

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

2、使用thymeleaf的语法;

<!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; 参考官方文档:https://www.thymeleaf.org/documentation.html pdf 2)、表达式? 4 Standard Expression Syntax We will take a small break in the development of our grocery virtual store to learn about one of the most important parts of the Thymeleaf Standard Dialect: the Thymeleaf Standard Expression syntax. We have already seen two types of valid attribute values expressed in this syntax: message and variable expressions: <p th:utext="#{home.welcome}">Welcome to our grocery store!</p> <p>Today is: <span th:text="${today}">13 february 2011</span></p> But there are more types of expressions, and more interesting details to learn about the ones we already know. First, let’s see a quick summary of the Standard Expression features: 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.

${param.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${}在功能上是一样的; 补充:配合 th:object="${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: #{...}获取国际化内容的; 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 Spring Boot 自动配置好了SpringMVC 以下是SpringBoot对SpringMVC的默认配置: 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; 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).ffavicon.ico; 自动注册了 of Converter, GenericConverter, Formatter beans. Convert:转换器,public String hello(User user):类型转换使用Convert Formatter:格式化器;2017-12-17===Date; 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) HttpMessageConverters :SpringMVC用来转换Http请求和响应的;User--json; HttpMessageConverters 是从容器中确定的;获取所有的 HttpMessageConverters ; 只需要自己将自己的组件注册在容器中;(@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) 1、初始化WebDataBinder; 2、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 既保留了所有的 自动配置,也能用我们扩展的配置;

<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

/**
 * Created by windMan on 2018/5/28
 */
//使用WebMvcConfigurerAdapter可以来扩展SpringMVC功能
@Configuration
public class MyMvcConfig extends WebMvcConfigurerAdapter {
    @Override
    public void addViewControllers(ViewControllerRegistry registry) {
//        super.addViewControllers(registry);
            //浏览器发送portalkjt请求到success
            registry.addViewController("/portalkjt").setViewName("success");
    }
}

原理: 1)、WebMvcAutoConfiguration 是SpringMvc的配置类; 2)、在做其他自动配置时会导入;@Import({WebMvcAutoConfiguration.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WebMvcConfigurater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WebMvcConfigurater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;

/**
 * Created by windMan on 2018/5/28
 */
//使用WebMvcConfigurerAdapter可以来扩展SpringMVC功能

@EnableWebMvc
@Configuration
public class MyMvcConfig extends WebMvcConfigurerAdapter {
    @Override
    public void addViewControllers(ViewControllerRegistry registry) {
//        super.addViewControllers(registry);
            //浏览器发送portalkjt请求到success
            registry.addViewController("/portalkjt").setViewName("success");
    }
}

原理: 为什么添加@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(
    type = Type.SERVLET
)
@ConditionalOnClass({Servlet.class, DispatcherServlet.class, WebMvcConfigurer.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(-2147483638)
@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 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xxConfigurater帮助我们进行扩展配置;

6、RestfulCRUD 1)、默认访问首页; 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;

@Bean
@ConfigurationProperties(prefix = "spring.messages")
public MessageSourceProperties messageSourceProperties() 
String basename = context.getEnvironment().getProperty("spring.messages.basename", "messages");//我们的配置文件可以直接放在类路径下叫message.properties;

@Bean
public MessageSource messageSource() {
    MessageSourceProperties properties = this.messageSourceProperties();
    ResourceBundleMessageSource messageSource = new ResourceBundleMessageSource();
    if (StringUtils.hasText(properties.getBasename())) {
//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(properties.getBasename())));
    }

    if (properties.getEncoding() != null) {
        messageSource.setDefaultEncoding(properties.getEncoding().name());
    }

    messageSource.setFallbackToSystemLocale(properties.isFallbackToSystemLocale());
    Duration cacheDuration = properties.getCacheDuration();
    if (cacheDuration != null) {
        messageSource.setCacheMillis(cacheDuration.toMillis());
    }

    messageSource.setAlwaysUseMessageFormat(properties.isAlwaysUseMessageFormat());
    messageSource.setUseCodeAsDefaultMessage(properties.isUseCodeAsDefaultMessage());
    return messageSource;
}

3)、去页面获取国际化的值; file-encording 文件及编码,根据当前浏览器语言设置的信息,切换的国际化;

原理: 国际化Locale(区域信息对象):LocalResolver(获取区域信息对象);

@Bean
@ConditionalOnMissingBean
@ConditionalOnProperty(
    prefix = "spring.mvc",
    name = {"locale"}
)
public LocaleResolver localeResolver() {
    if (this.mvcProperties.getLocaleResolver() == org.springframework.boot.autoconfigure.web.servlet.WebMvcProperties.LocaleResolver.FIXED) {
        return new FixedLocaleResolver(this.mvcProperties.getLocale());
    } else {
        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;

/**
 * Created by windMan on 2018/5/28
 * 可以在链接上携带区域信息
 */
public class MyLocalResolver 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 Local(split[0],split[1]);
        }
        return locale;
    }

    @Override
    public void setLocale(HttpServletRequest request, @Nullable HttpServletResponse response, @Nullable Locale locale) {

    }
}


@Bean
public LocaleResolver localeResolver(){
    return new MyLocalResolver();
}

3)、登录 开发期间模版引擎页面修改后,要实时生效; 1)、禁用模版引擎的缓存 #禁用缓存 spring.thymeleaf.cache=false 2)、页面修改完成后ctrl+f9:重新编辑; 登录错误消息的 显示;

3)、拦截器进行登录检查

 //注册拦截器
            @Override
            public void addInterceptors(InterceptorRegistry registry) {
//                super.addInterceptors(registry);
                    //静态资源:*.css ,*.js
                    //SpringBoot已经 做好了静态资源的映射
                    registry.addInterceptor(new LoginHandlerInterceptor()).addPathPatterns("/**")
                            .excludePathPatterns("index.html","/","user/login");
            }

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}:模版名::选择器
~{templatename::fragmentname}:模版名::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:
<div th:replace="::frag (onevar=${value1},twovar=${value2})">
${#dates.format(date, 'dd/MMM/yyyy HH:mm')}


日期的格式化;SpringMVC将页面提交的值需要转换为指定的类型;
类型转换,格式化;
默认日期是按照/的方式;

本文参与腾讯云自媒体分享计划,欢迎正在阅读的你也加入,一起分享。

发表于

我来说两句

0 条评论
登录 后参与评论

扫码关注云+社区

领取腾讯云代金券

年度创作总结 领取年终奖励