四、Web開發 2
6、RestfulCRUD
1)、預設訪問首頁
//使用WebMvcConfigurerAdapter可以來擴充套件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); //瀏覽器傳送 /atguigu 請求來到 success registry.addViewController("/atguigu").setViewName("success"); } //所有的WebMvcConfigurerAdapter元件都會一起起作用 @Bean //將元件註冊在容器 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)、國際化
1)、編寫國際化配置檔案;
2)、使用ResourceBundleMessageSource管理國際化資原始檔
3)、在頁面使用fmt:message取出國際化內容
步驟:
1)、編寫國際化配置檔案,抽取頁面需要顯示的國際化訊息
2)、SpringBoot自動配置好了管理國際化資原始檔的元件;
@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"; //我們的配置檔案可以直接放在類路徑下叫messages.properties; @Bean public MessageSource messageSource() { ResourceBundleMessageSource messageSource = new ResourceBundleMessageSource(); if (StringUtils.hasText(this.basename)) { //設定國際化資原始檔的基礎名(去掉語言國家程式碼的) 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)、去頁面獲取國際化的值;
<!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:根據瀏覽器語言設定的資訊切換了國際化;
原理:
國際化Locale(區域資訊物件);LocaleResolver(獲取區域資訊物件);
@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;
}
預設的就是根據請求頭帶來的區域資訊獲取Locale進行國際化
4)、點選連結切換國際化
/**
* 可以在連線上攜帶區域資訊
*/
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)、登陸
開發期間模板引擎頁面修改以後,要實時生效
1)、禁用模板引擎的快取
# 禁用快取
spring.thymeleaf.cache=false
2)、頁面修改完成以後ctrl+f9:重新編譯;
登陸錯誤訊息的顯示
<p style="color: red" th:text="${msg}" th:if="${not #strings.isEmpty(msg)}"></p>
4)、攔截器進行登陸檢查
攔截器
/**
* 登陸檢查,
*/
public class LoginHandlerInterceptor implements HandlerInterceptor {
//目標方法執行之前
@Override
public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
Object user = request.getSession().getAttribute("loginUser");
if(user == null){
//未登陸,返回登陸頁面
request.setAttribute("msg","沒有許可權請先登陸");
request.getRequestDispatcher("/index.html").forward(request,response);
return false;
}else{
//已登陸,放行請求
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 {
}
}
註冊攔截器
//所有的WebMvcConfigurerAdapter元件都會一起起作用
@Bean //將元件註冊在容器
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");
}
//註冊攔截器
@Override
public void addInterceptors(InterceptorRegistry registry) {
//super.addInterceptors(registry);
//靜態資源; *.css , *.js
//SpringBoot已經做好了靜態資源對映
registry.addInterceptor(new LoginHandlerInterceptor()).addPathPatterns("/**")
.excludePathPatterns("/index.html","/","/user/login");
}
};
return adapter;
}
5)、CRUD-員工列表
實驗要求:
1)、RestfulCRUD:CRUD滿足Rest風格;
URI: /資源名稱/資源標識 HTTP請求方式區分對資源CRUD操作
普通CRUD(uri來區分操作) | RestfulCRUD | |
---|---|---|
查詢 | getEmp | emp---GET |
新增 | addEmp?xxx | emp---POST |
修改 | updateEmp?id=xxx&xxx=xx | emp/{id}---PUT |
刪除 | deleteEmp?id=1 | emp/{id}---DELETE |
2)、實驗的請求架構;
實驗功能 | 請求URI | 請求方式 |
---|---|---|
查詢所有員工 | emps | GET |
查詢某個員工(來到修改頁面) | emp/1 | GET |
來到新增頁面 | emp | GET |
新增員工 | emp | POST |
來到修改頁面(查出員工進行資訊回顯) | emp/1 | GET |
修改員工 | emp | PUT |
刪除員工 | emp/1 | DELETE |
3)、員工列表:
thymeleaf公共頁面元素抽取
1、抽取公共片段
<div th:fragment="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::選擇器
~{templatename::fragmentname}:模板名::片段名
3、預設效果:
insert的公共片段在div標籤中
如果使用th:insert等屬性進行引入,可以不用寫~{}:
行內寫法可以加上:[[~{}]];[(~{})];
三種引入公共片段的th屬性:
th:insert:將公共片段整個插入到宣告引入的元素中
th:replace:將宣告引入的元素替換為公共片段
th:include:將被引入的片段的內容包含進這個標籤中
<footer th:fragment="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>
© 2011 The Good Thymes Virtual Grocery
</footer>
</div>
<footer>
© 2011 The Good Thymes Virtual Grocery
</footer>
<div>
© 2011 The Good Thymes Virtual Grocery
</div>
引入片段的時候傳入引數:
<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>
<!--引入側邊欄;傳入引數-->
<div th:replace="commons/bar::#sidebar(activeUri='emps')"></div>
6)、CRUD-員工新增
新增頁面
<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="[email protected]">
</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">新增</button>
</form>
提交的資料格式不對:生日:日期;
2017-12-12;2017/12/12;2017.12.12;
日期的格式化;SpringMVC將頁面提交的值需要轉換為指定的型別;
2017-12-12---Date; 型別轉換,格式化;
預設日期是按照/的方式;
7)、CRUD-員工修改
修改新增二合一表單
<!--需要區分是員工修改還是新增;-->
<form th:action="@{/emp}" method="post">
<!--傳送put請求修改員工資料-->
<!--
1、SpringMVC中配置HiddenHttpMethodFilter;(SpringBoot自動配置好的)
2、頁面建立一個post表單
3、建立一個input項,name="_method";值就是我們指定的請求方式
-->
<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="[email protected]" 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>
<!--提交的是部門的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':'新增'">新增</button>
</form>
8)、CRUD-員工刪除
<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}">編輯</a>
<button th:attr="del_uri=@{/emp/}+${emp.id}" class="btn btn-sm btn-danger deleteBtn">刪除</button>
</td>
</tr>
<script>
$(".deleteBtn").click(function(){
//刪除當前員工的
$("#deleteEmpForm").attr("action",$(this).attr("del_uri")).submit();
return false;
});
</script>
7、錯誤處理機制
1)、SpringBoot預設的錯誤處理機制
預設效果:
1)、瀏覽器,返回一個預設的錯誤頁面
瀏覽器傳送請求的請求頭:
2)、如果是其他客戶端,預設響應一個json資料
原理:
可以參照ErrorMvcAutoConfiguration;錯誤處理的自動配置;
給容器中添加了以下元件
1、DefaultErrorAttributes:
幫我們在頁面共享資訊;
@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:處理預設/error請求
@Controller
@RequestMapping("${server.error.path:${error.path:/error}}")
public class BasicErrorController extends AbstractErrorController {
@RequestMapping(produces = "text/html")//產生html型別的資料;瀏覽器傳送的請求來到這個方法處理
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());
//去哪個頁面作為錯誤頁面;包含頁面地址和頁面內容
ModelAndView modelAndView = resolveErrorView(request, response, status, model);
return (modelAndView == null ? new ModelAndView("error", model) : modelAndView);
}
@RequestMapping
@ResponseBody //產生json資料,其他客戶端來到這個方法處理;
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"; 系統出現錯誤以後來到error請求進行處理;(web.xml註冊的錯誤頁面規則)
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) {
//預設SpringBoot可以去找到一個頁面? error/404
String errorViewName = "error/" + viewName;
//模板引擎可以解析這個頁面地址就用模板引擎解析
TemplateAvailabilityProvider provider = this.templateAvailabilityProviders
.getProvider(errorViewName, this.applicationContext);
if (provider != null) {
//模板引擎可用的情況下返回到errorViewName指定的檢視地址
return new ModelAndView(errorViewName, model);
}
//模板引擎不可用,就在靜態資原始檔夾下找errorViewName對應的頁面 error/404.html
return resolveResource(errorViewName, model);
}
步驟:
一但系統出現4xx或者5xx之類的錯誤;ErrorPageCustomizer就會生效(定製錯誤的響應規則);就會來到/error請求;就會被BasicErrorController處理;
1)響應頁面;去哪個頁面是由DefaultErrorViewResolver解析得到的;
protected ModelAndView resolveErrorView(HttpServletRequest request,
HttpServletResponse response, HttpStatus status, Map<String, Object> model) {
//所有的ErrorViewResolver得到ModelAndView
for (ErrorViewResolver resolver : this.errorViewResolvers) {
ModelAndView modelAndView = resolver.resolveErrorView(request, status, model);
if (modelAndView != null) {
return modelAndView;
}
}
return null;
}
2)、如果定製錯誤響應:
1)、如何定製錯誤的頁面;
1)、有模板引擎的情況下;error/狀態碼; 【將錯誤頁面命名為 錯誤狀態碼.html 放在模板引擎資料夾裡面的 error資料夾下】,發生此狀態碼的錯誤就會來到 對應的頁面;
我們可以使用4xx和5xx作為錯誤頁面的檔名來匹配這種型別的所有錯誤,精確優先(優先尋找精確的狀態碼.html);
頁面能獲取的資訊;
timestamp:時間戳
status:狀態碼
error:錯誤提示
exception:異常物件
message:異常訊息
errors:JSR303資料校驗的錯誤都在這裡
2)、沒有模板引擎(模板引擎找不到這個錯誤頁面),靜態資原始檔夾下找;
3)、以上都沒有錯誤頁面,就是預設來到SpringBoot預設的錯誤提示頁面;
2)、如何定製錯誤的json資料;
1)、自定義異常處理&返回定製json資料;
@ControllerAdvice
public class MyExceptionHandler {
@ResponseBody
@ExceptionHandler(UserNotExistException.class)
public Map<String,Object> handleException(Exception e){
Map<String,Object> map = new HashMap<>();
map.put("code","user.notexist");
map.put("message",e.getMessage());
return map;
}
}
//沒有自適應效果...
2)、轉發到/error進行自適應響應效果處理
@ExceptionHandler(UserNotExistException.class)
public String handleException(Exception e, HttpServletRequest request){
Map<String,Object> map = new HashMap<>();
//傳入我們自己的錯誤狀態碼 4xx 5xx,否則就不會進入定製錯誤頁面的解析流程
/**
* Integer statusCode = (Integer) request
.getAttribute("javax.servlet.error.status_code");
*/
request.setAttribute("javax.servlet.error.status_code",500);
map.put("code","user.notexist");
map.put("message",e.getMessage());
//轉發到/error
return "forward:/error";
}
3)、將我們的定製資料攜帶出去;
出現錯誤以後,會來到/error請求,會被BasicErrorController處理,響應出去可以獲取的資料是由getErrorAttributes得到的(是AbstractErrorController(ErrorController)規定的方法);
1、完全來編寫一個ErrorController的實現類【或者是編寫AbstractErrorController的子類】,放在容器中;
2、頁面上能用的資料,或者是json返回能用的資料都是通過errorAttributes.getErrorAttributes得到;
容器中DefaultErrorAttributes.getErrorAttributes();預設進行資料處理的;
自定義ErrorAttributes
//給容器中加入我們自己定義的ErrorAttributes
@Component
public class MyErrorAttributes extends DefaultErrorAttributes {
@Override
public Map<String, Object> getErrorAttributes(RequestAttributes requestAttributes, boolean includeStackTrace) {
Map<String, Object> map = super.getErrorAttributes(requestAttributes, includeStackTrace);
map.put("company","atguigu");
return map;
}
}
最終的效果:響應是自適應的,可以通過定製ErrorAttributes改變需要返回的內容,
8、配置嵌入式Servlet容器
SpringBoot預設使用Tomcat作為嵌入式的Servlet容器;
問題?
1)、如何定製和修改Servlet容器的相關配置;
1、修改和server有關的配置(ServerProperties【也是EmbeddedServletContainerCustomizer】);
server.port=8081
server.context-path=/crud
server.tomcat.uri-encoding=UTF-8
//通用的Servlet容器設定
server.xxx
//Tomcat的設定
server.tomcat.xxx
2、編寫一個EmbeddedServletContainerCustomizer:嵌入式的Servlet容器的定製器;來修改Servlet容器的配置
@Bean //一定要將這個定製器加入到容器中
public EmbeddedServletContainerCustomizer embeddedServletContainerCustomizer(){
return new EmbeddedServletContainerCustomizer() {
//定製嵌入式的Servlet容器相關的規則
@Override
public void customize(ConfigurableEmbeddedServletContainer container) {
container.setPort(8083);
}
};
}
2)、註冊Servlet三大元件【Servlet、Filter、Listener】
由於SpringBoot預設是以jar包的方式啟動嵌入式的Servlet容器來啟動SpringBoot的web應用,沒有web.xml檔案。
註冊三大元件用以下方式
ServletRegistrationBean
//註冊三大元件
@Bean
public ServletRegistrationBean myServlet(){
ServletRegistrationBean registrationBean = new ServletRegistrationBean(new MyServlet(),"/myServlet");
return registrationBean;
}
FilterRegistrationBean
@Bean
public FilterRegistrationBean myFilter(){
FilterRegistrationBean registrationBean = new FilterRegistrationBean();
registrationBean.setFilter(new MyFilter());
registrationBean.setUrlPatterns(Arrays.asList("/hello","/myServlet"));
return registrationBean;
}
ServletListenerRegistrationBean
@Bean
public ServletListenerRegistrationBean myListener(){
ServletListenerRegistrationBean<MyListener> registrationBean = new ServletListenerRegistrationBean<>(new MyListener());
return registrationBean;
}
SpringBoot幫我們自動SpringMVC的時候,自動的註冊SpringMVC的前端控制器;DIspatcherServlet;
DispatcherServletAutoConfiguration中:
@Bean(name = DEFAULT_DISPATCHER_SERVLET_REGISTRATION_BEAN_NAME)
@ConditionalOnBean(value = DispatcherServlet.class, name = DEFAULT_DISPATCHER_SERVLET_BEAN_NAME)
public ServletRegistrationBean dispatcherServletRegistration(
DispatcherServlet dispatcherServlet) {
ServletRegistrationBean registration = new ServletRegistrationBean(
dispatcherServlet, this.serverProperties.getServletMapping());
//預設攔截: / 所有請求;包靜態資源,但是不攔截jsp請求; /*會攔截jsp
//可以通過server.servletPath來修改SpringMVC前端控制器預設攔截的請求路徑
registration.setName(DEFAULT_DISPATCHER_SERVLET_BEAN_NAME);
registration.setLoadOnStartup(
this.webMvcProperties.getServlet().getLoadOnStartup());
if (this.multipartConfig != null) {
registration.setMultipartConfig(this.multipartConfig);
}
return registration;
}
2)、SpringBoot能不能支援其他的Servlet容器;
3)、替換為其他嵌入式Servlet容器
預設支援:
Tomcat(預設使用)
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
引入web模組預設就是使用嵌入式的Tomcat作為Servlet容器;
</dependency>
Jetty
<!-- 引入web模組 -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
<exclusions>
<exclusion>
<artifactId>spring-boot-starter-tomcat</artifactId>
<groupId>org.springframework.boot</groupId>
</exclusion>
</exclusions>
</dependency>
<!--引入其他的Servlet容器-->
<dependency>
<artifactId>spring-boot-starter-jetty</artifactId>
<groupId>org.springframework.boot</groupId>
</dependency>
Undertow
<!-- 引入web模組 -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
<exclusions>
<exclusion>
<artifactId>spring-boot-starter-tomcat</artifactId>
<groupId>org.springframework.boot</groupId>
</exclusion>
</exclusions>
</dependency>
<!--引入其他的Servlet容器-->
<dependency>
<artifactId>spring-boot-starter-undertow</artifactId>
<groupId>org.springframework.boot</groupId>
</dependency>
4)、嵌入式Servlet容器自動配置原理;
EmbeddedServletContainerAutoConfiguration:嵌入式的Servlet容器自動配置?
@AutoConfigureOrder(Ordered.HIGHEST_PRECEDENCE)
@Configuration
@ConditionalOnWebApplication
@Import(BeanPostProcessorsRegistrar.class)
//匯入BeanPostProcessorsRegistrar:Spring註解版;給容器中匯入一些元件
//匯入了EmbeddedServletContainerCustomizerBeanPostProcessor:
//後置處理器:bean初始化前後(建立完物件,還沒賦值賦值)執行初始化工作
public class EmbeddedServletContainerAutoConfiguration {
@Configuration
@ConditionalOnClass({ Servlet.class, Tomcat.class })//判斷當前是否引入了Tomcat依賴;
@ConditionalOnMissingBean(value = EmbeddedServletContainerFactory.class, search = SearchStrategy.CURRENT)//判斷當前容器沒有使用者自己定義EmbeddedServletContainerFactory:嵌入式的Servlet容器工廠;作用:建立嵌入式的Servlet容器
public static class EmbeddedTomcat {
@Bean
public TomcatEmbeddedServletContainerFactory tomcatEmbeddedServletContainerFactory() {
return new TomcatEmbeddedServletContainerFactory();
}
}
/**
* Nested configuration if Jetty is being used.
*/
@Configuration
@ConditionalOnClass({ Servlet.class, Server.class, Loader.class,
WebAppContext.class })
@ConditionalOnMissingBean(value = EmbeddedServletContainerFactory.class, search = SearchStrategy.CURRENT)
public static class EmbeddedJetty {
@Bean
public JettyEmbeddedServletContainerFactory jettyEmbeddedServletContainerFactory() {
return new JettyEmbeddedServletContainerFactory();
}
}
/**
* Nested configuration if Undertow is being used.
*/
@Configuration
@ConditionalOnClass({ Servlet.class, Undertow.class, SslClientAuthMode.class })
@ConditionalOnMissingBean(value = EmbeddedServletContainerFactory.class, search = SearchStrategy.CURRENT)
public static class EmbeddedUndertow {
@Bean
public UndertowEmbeddedServletContainerFactory undertowEmbeddedServletContainerFactory() {
return new UndertowEmbeddedServletContainerFactory();
}
}
1)、EmbeddedServletContainerFactory(嵌入式Servlet容器工廠)
public interface EmbeddedServletContainerFactory {
//獲取嵌入式的Servlet容器
EmbeddedServletContainer getEmbeddedServletContainer(
ServletContextInitializer... initializers);
}
2)、EmbeddedServletContainer:(嵌入式的Servlet容器)
3)、以TomcatEmbeddedServletContainerFactory為例
@Override
public EmbeddedServletContainer getEmbeddedServletContainer(
ServletContextInitializer... initializers) {
//建立一個Tomcat
Tomcat tomcat = new Tomcat();
//配置Tomcat的基本環節
File baseDir = (this.baseDirectory != null ? this.baseDirectory
: createTempDir("tomcat"));
tomcat.setBaseDir(baseDir.getAbsolutePath());
Connector connector = new Connector(this.protocol);
tomcat.getService().addConnector(connector);
customizeConnector(connector);
tomcat.setConnector(connector);
tomcat.getHost().setAutoDeploy(false);
configureEngine(tomcat.getEngine());
for (Connector additionalConnector : this.additionalTomcatConnectors) {
tomcat.getService().addConnector(additionalConnector);
}
prepareContext(tomcat.getHost(), initializers);
//將配置好的Tomcat傳入進去,返回一個EmbeddedServletContainer;並且啟動Tomcat伺服器
return getTomcatEmbeddedServletContainer(tomcat);
}
4)、我們對嵌入式容器的配置修改是怎麼生效?
ServerProperties、EmbeddedServletContainerCustomizer
EmbeddedServletContainerCustomizer:定製器幫我們修改了Servlet容器的配置?
怎麼修改的原理?
5)、容器中匯入了EmbeddedServletContainerCustomizerBeanPostProcessor
//初始化之前
@Override
public Object postProcessBeforeInitialization(Object bean, String beanName)
throws BeansException {
//如果當前初始化的是一個ConfigurableEmbeddedServletContainer型別的元件
if (bean instanceof ConfigurableEmbeddedServletContainer) {
//
postProcessBeforeInitialization((ConfigurableEmbeddedServletContainer) bean);
}
return bean;
}
private void postProcessBeforeInitialization(
ConfigurableEmbeddedServletContainer bean) {
//獲取所有的定製器,呼叫每一個定製器的customize方法來給Servlet容器進行屬性賦值;
for (EmbeddedServletContainerCustomizer customizer : getCustomizers()) {
customizer.customize(bean);
}
}
private Collection<EmbeddedServletContainerCustomizer> getCustomizers() {
if (this.customizers == null) {
// Look up does not include the parent context
this.customizers = new ArrayList<EmbeddedServletContainerCustomizer>(
this.beanFactory
//從容器中獲取所有這葛型別的元件:EmbeddedServletContainerCustomizer
//定製Servlet容器,給容器中可以新增一個EmbeddedServletContainerCustomizer型別的元件
.getBeansOfType(EmbeddedServletContainerCustomizer.class,
false, false)
.values());
Collections.sort(this.customizers, AnnotationAwareOrderComparator.INSTANCE);
this.customizers = Collections.unmodifiableList(this.customizers);
}
return this.customizers;
}
ServerProperties也是定製器
步驟:
1)、SpringBoot根據匯入的依賴情況,給容器中新增相應的EmbeddedServletContainerFactory【TomcatEmbeddedServletContainerFactory】
2)、容器中某個元件要建立物件就會驚動後置處理器;EmbeddedServletContainerCustomizerBeanPostProcessor;
只要是嵌入式的Servlet容器工廠,後置處理器就工作;
3)、後置處理器,從容器中獲取所有的EmbeddedServletContainerCustomizer,呼叫定製器的定製方法
5)、嵌入式Servlet容器啟動原理;
什麼時候建立嵌入式的Servlet容器工廠?什麼時候獲取嵌入式的Servlet容器並啟動Tomcat;
獲取嵌入式的Servlet容器工廠:
1)、SpringBoot應用啟動執行run方法
2)、refreshContext(context);SpringBoot重新整理IOC容器【建立IOC容器物件,並初始化容器,建立容器中的每一個元件】;如果是web應用建立AnnotationConfigEmbeddedWebApplicationContext,否則:AnnotationConfigApplicationContext
3)、refresh(context);重新整理剛才建立好的ioc容器;
public void refresh() throws BeansException, IllegalStateException {
synchronized (this.startupShutdownMonitor) {
// Prepare this context for refreshing.
prepareRefresh();
// Tell the subclass to refresh the internal bean factory.
ConfigurableListableBeanFactory beanFactory = obtainFreshBeanFactory();
// Prepare the bean factory for use in this context.
prepareBeanFactory(beanFactory);
try {
// Allows post-processing of the bean factory in context subclasses.
postProcessBeanFactory(beanFactory);
// Invoke factory processors registered as beans in the context.
invokeBeanFactoryPostProcessors(beanFactory);
// Register bean processors that intercept bean creation.
registerBeanPostProcessors(beanFactory);
// Initialize message source for this context.
initMessageSource();
// Initialize event multicaster for this context.
initApplicationEventMulticaster();
// Initialize other special beans in specific context subclasses.
onRefresh();
// Check for listener beans and register them.
registerListeners();
// Instantiate all remaining (non-lazy-init) singletons.
finishBeanFactoryInitialization(beanFactory);
// Last step: publish corresponding event.
finishRefresh();
}
catch (BeansException ex) {
if (logger.isWarnEnabled()) {
logger.warn("Exception encountered during context initialization - " +
"cancelling refresh attempt: " + ex);
}
// Destroy already created singletons to avoid dangling resources.
destroyBeans();
// Reset 'active' flag.
cancelRefresh(ex);
// Propagate exception to caller.
throw ex;
}
finally {
// Reset common introspection caches in Spring's core, since we
// might not ever need metadata for singleton beans anymore...
resetCommonCaches();
}
}
}
4)、 onRefresh(); web的ioc容器重寫了onRefresh方法
5)、webioc容器會建立嵌入式的Servlet容器;createEmbeddedServletContainer();
6)、獲取嵌入式的Servlet容器工廠:
EmbeddedServletContainerFactory containerFactory = getEmbeddedServletContainerFactory();
從ioc容器中獲取EmbeddedServletContainerFactory 元件;TomcatEmbeddedServletContainerFactory建立物件,後置處理器一看是這個物件,就獲取所有的定製器來先定製Servlet容器的相關配置;
7)、使用容器工廠獲取嵌入式的Servlet容器:this.embeddedServletContainer = containerFactory .getEmbeddedServletContainer(getSelfInitializer());
8)、嵌入式的Servlet容器建立物件並啟動Servlet容器;
先啟動嵌入式的Servlet容器,再將ioc容器中剩下沒有創建出的物件獲取出來;
IOC容器啟動建立嵌入式的Servlet容器
9、使用外接的Servlet容器
嵌入式Servlet容器:應用打成可執行的jar
優點:簡單、便攜;
缺點:預設不支援JSP、優化定製比較複雜(使用定製器【ServerProperties、自定義EmbeddedServletContainerCustomizer】,自己編寫嵌入式Servlet容器的建立工廠【EmbeddedServletContainerFactory】);
外接的Servlet容器:外面安裝Tomcat---應用war包的方式打包;
步驟
1)、必須建立一個war專案;(利用idea建立好目錄結構)
2)、將嵌入式的Tomcat指定為provided;
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-tomcat</artifactId>
<scope>provided</scope>
</dependency>
3)、必須編寫一個SpringBootServletInitializer的子類,並呼叫configure方法
public class ServletInitializer extends SpringBootServletInitializer {
@Override
protected SpringApplicationBuilder configure(SpringApplicationBuilder application) {
//傳入SpringBoot應用的主程式
return application.sources(SpringBoot04WebJspApplication.class);
}
}
4)、啟動伺服器就可以使用;
原理
jar包:執行SpringBoot主類的main方法,啟動ioc容器,建立嵌入式的Servlet容器;
war包:啟動伺服器,伺服器啟動SpringBoot應用【SpringBootServletInitializer】,啟動ioc容器;
servlet3.0(Spring註解版):
8.2.4 Shared libraries / runtimes pluggability:
規則:
1)、伺服器啟動(web應用啟動)會建立當前web應用裡面每一個jar包裡面ServletContainerInitializer例項:
2)、ServletContainerInitializer的實現放在jar包的META-INF/services資料夾下,有一個名為javax.servlet.ServletContainerInitializer的檔案,內容就是ServletContainerInitializer的實現類的全類名
3)、還可以使用@HandlesTypes,在應用啟動的時候載入我們感興趣的類;
流程:
1)、啟動Tomcat
2)、org\springframework\spring-web\4.3.14.RELEASE\spring-web-4.3.14.RELEASE.jar!\META-INF\services\javax.servlet.ServletContainerInitializer:
Spring的web模組裡面有這個檔案:org.springframework.web.SpringServletContainerInitializer
3)、SpringServletContainerInitializer將@HandlesTypes(WebApplicationInitializer.class)標註的所有這個型別的類都傳入到onStartup方法的Set<Class<?>>;為這些WebApplicationInitializer型別的類建立例項;
4)、每一個WebApplicationInitializer都呼叫自己的onStartup;
5)、相當於我們的SpringBootServletInitializer的類會被建立物件,並執行onStartup方法
6)、SpringBootServletInitializer例項執行onStartup的時候會createRootApplicationContext;建立容器
protected WebApplicationContext createRootApplicationContext(
ServletContext servletContext) {
//1、建立SpringApplicationBuilder
SpringApplicationBuilder builder = createSpringApplicationBuilder();
StandardServletEnvironment environment = new StandardServletEnvironment();
environment.initPropertySources(servletContext, null);
builder.environment(environment);
builder.main(getClass());
ApplicationContext parent = getExistingRootWebApplicationContext(servletContext);
if (parent != null) {
this.logger.info("Root context already created (using as parent).");
servletContext.setAttribute(
WebApplicationContext.ROOT_WEB_APPLICATION_CONTEXT_ATTRIBUTE, null);
builder.initializers(new ParentContextApplicationContextInitializer(parent));
}
builder.initializers(
new ServletContextApplicationContextInitializer(servletContext));
builder.contextClass(AnnotationConfigEmbeddedWebApplicationContext.class);
//呼叫configure方法,子類重寫了這個方法,將SpringBoot的主程式類傳入了進來
builder = configure(builder);
//使用builder建立一個Spring應用
SpringApplication application = builder.build();
if (application.getSources().isEmpty() && AnnotationUtils
.findAnnotation(getClass(), Configuration.class) != null) {
application.getSources().add(getClass());
}
Assert.state(!application.getSources().isEmpty(),
"No SpringApplication sources have been defined. Either override the "
+ "configure method or add an @Configuration annotation");
// Ensure error pages are registered
if (this.registerErrorPageFilter) {
application.getSources().add(ErrorPageFilterConfiguration.class);
}
//啟動Spring應用
return run(application);
}
7)、Spring的應用就啟動並且建立IOC容器
public ConfigurableApplicationContext run(String... args) {
StopWatch stopWatch = new StopWatch();
stopWatch.start();
ConfigurableApplicationContext context = null;
FailureAnalyzers analyzers = null;
configureHeadlessProperty();
SpringApplicationRunListeners listeners = getRunListeners(args);
listeners.starting();
try {
ApplicationArguments applicationArguments = new DefaultApplicationArguments(
args);
ConfigurableEnvironment environment = prepareEnvironment(listeners,
applicationArguments);
Banner printedBanner = printBanner(environment);
context = createApplicationContext();
analyzers = new FailureAnalyzers(context);
prepareContext(context, environment, listeners, applicationArguments,
printedBanner);
//重新整理IOC容器
refreshContext(context);
afterRefresh(context, applicationArguments);
listeners.finished(context, null);
stopWatch.stop();
if (this.logStartupInfo) {
new StartupInfoLogger(this.mainApplicationClass)
.logStarted(getApplicationLog(), stopWatch);
}
return context;
}
catch (Throwable ex) {
handleRunFailure(context, listeners, analyzers, ex);
throw new IllegalStateException(ex);
}
}
啟動Servlet容器,再啟動SpringBoot應用