原理分析
1、web容器在啓動的時候,會掃描每個jar包下的META-INF/services/javax.servlet.ServletContainerInitializer
2、加載這個文件指定的類SpringServletContainerInitializer
3、spring的應用一啓動會加載感興趣的WebApplicationInitializer接口的下的所有組件;
4、並且爲WebApplicationInitializer組件創建對象(組件不是接口,不是抽象類)
1)、AbstractContextLoaderInitializer:創建根容器;createRootApplicationContext();
2)、AbstractDispatcherServletInitializer:
創建一個web的ioc容器;createServletApplicationContext();
創建了DispatcherServlet;createDispatcherServlet();
將創建的DispatcherServlet添加到ServletContext中;
getServletMappings();
3)、AbstractAnnotationConfigDispatcherServletInitializer:註解方式配置的DispatcherServlet初始化器
創建根容器:createRootApplicationContext()
getRootConfigClasses();傳入一個配置類
創建web的ioc容器: createServletApplicationContext();
獲取配置類;getServletConfigClasses();
總結
以註解方式來啓動SpringMVC;繼承AbstractAnnotationConfigDispatcherServletInitializer;實現抽象方法指定DispatcherServlet的配置信息;
SpringMVC整合
1、首先創建一個maven項目,添加依賴
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.atguigu</groupId>
<artifactId>springmvc-annotation</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>war</packaging>
<dependencies>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
<version>4.3.11.RELEASE</version>
</dependency>
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>servlet-api</artifactId>
<version>3.0-alpha-1</version>
<scope>provided</scope>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-war-plugin</artifactId>
<version>2.4</version>
<configuration>
<failOnMissingWebXml>false</failOnMissingWebXml>
</configuration>
</plugin>
</plugins>
</build>
</project>
2、創建MyWebAppInitializer繼承AbstractAnnotationConfigDispatcherServletInitializer
//web容器啓動的時候創建對象;調用方法來初始化容器以前前端控制器
public class MyWebAppInitializer extends AbstractAnnotationConfigDispatcherServletInitializer {
//獲取根容器的配置類;(Spring的配置文件) 父容器;不掃描controller
@Override
protected Class<?>[] getRootConfigClasses() {
// TODO Auto-generated method stub
return new Class<?>[]{RootConfig.class};
}
//獲取web容器的配置類(SpringMVC配置文件) 子容器;業務邏輯有關,只掃描controller
@Override
protected Class<?>[] getServletConfigClasses() {
// TODO Auto-generated method stub
return new Class<?>[]{AppConfig.class};
}
//獲取DispatcherServlet的映射信息
// /:攔截所有請求(包括靜態資源(xx.js,xx.png)),但是不包括*.jsp;
// /*:攔截所有請求;連*.jsp頁面都攔截;jsp頁面是tomcat的jsp引擎解析的;
@Override
protected String[] getServletMappings() {
// TODO Auto-generated method stub
return new String[]{"/"};
}
}
3、添加配置信息
AppConfig.java
//SpringMVC只掃描Controller;子容器
//useDefaultFilters=false 禁用默認的過濾規則;
@ComponentScan(value="com.atguigu",includeFilters={
@Filter(type=FilterType.ANNOTATION,classes={Controller.class})
},useDefaultFilters=false)
@EnableWebMvc
public class AppConfig implement WebMvcConfigurer {
}
RootConfig.java
//Spring的容器不掃描controller;父容器
@ComponentScan(value="com.atguigu",excludeFilters={
@Filter(type=FilterType.ANNOTATION,classes={Controller.class})
})
public class RootConfig {
}
4、添加controller
@Controller
public class HelloController {
@Autowired
HelloService helloService;
@ResponseBody
@RequestMapping("/hello")
public String hello(){
String hello = helloService.sayHello("tomcat..");
return hello;
}
// /WEB-INF/views/success.jsp
@RequestMapping("/suc")
public String success(){
return "success";
}
}
5、添加service
@Service
public class HelloService {
public String sayHello(String name){
return "Hello "+name;
}
}
6、啓動項目訪問
定製與接管SpringMVC
我們使用xml配置文件時可以進行很多配置,現在不用xml配置要怎麼做呢
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:mvc="http://www.springframework.org/schema/mvc"
xsi:schemaLocation="http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-4.3.xsd
http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">
<!--將SpringMVC處理不了的請求交給tomcat;靜態資源 就可以訪問 -->
<mvc:default-servlet-handler/>
<!-- SpringMVC的高級功能開啓 -->
<mvc:annotation-driven />
<!-- <mvc:interceptors>
</mvc:interceptors>
<mvc:view-controller path=""/> -->
</beans>
定製SpringMVC
1)@EnableWebMvc:開啓SpringMVC定製配置功能;
<mvc:annotation-driven/>
2)配置組件(視圖解析器、視圖映射、靜態資源映射、攔截器。。。)
extends WebMvcConfigurerAdapter
在AppConfig中添加配置,實現WebMvcConfigurer需要實現很多方法但是一般不需要那麼多。可以換用WebMvcConfigurerAdapter適配器進行適配,添加需要定製的方法。
//SpringMVC只掃描Controller;子容器
//useDefaultFilters=false 禁用默認的過濾規則;
@ComponentScan(value="com.atguigu",includeFilters={
@Filter(type=FilterType.ANNOTATION,classes={Controller.class})
},useDefaultFilters=false)
@EnableWebMvc
public class AppConfig extends WebMvcConfigurerAdapter {
//定製
//視圖解析器
@Override
public void configureViewResolvers(ViewResolverRegistry registry) {
// TODO Auto-generated method stub
//默認所有的頁面都從 /WEB-INF/ xxx .jsp
//registry.jsp();
registry.jsp("/WEB-INF/views/", ".jsp");
}
//靜態資源訪問
@Override
public void configureDefaultServletHandling(DefaultServletHandlerConfigurer configurer) {
// TODO Auto-generated method stub
configurer.enable();
}
//攔截器
@Override
public void addInterceptors(InterceptorRegistry registry) {
// TODO Auto-generated method stub
//super.addInterceptors(registry);
registry.addInterceptor(new MyFirstInterceptor()).addPathPatterns("/**");
}
}
添加攔截器
public class MyFirstInterceptor implements HandlerInterceptor {
//目標方法運行之前執行
@Override
public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
throws Exception {
// TODO Auto-generated method stub
System.out.println("preHandle..."+request.getRequestURI());
return true;
}
//目標方法執行正確以後執行
@Override
public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler,
ModelAndView modelAndView) throws Exception {
// TODO Auto-generated method stub
System.out.println("postHandle...");
}
//頁面響應以後執行
@Override
public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex)
throws Exception {
// TODO Auto-generated method stub
System.out.println("afterCompletion...");
}
}
視圖解析器
/WEB-INF/views/下添加index.jsp,訪問會進入jsp頁面
靜態資源訪問
在jsp頁面並引入圖片,運行jsp發現圖片可以訪問
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
<img alt="" src="upload_3.jpg">
</body>
</html>
攔截器
啓動項目進行訪問的時候,發現攔截器生效