搭建SpringMVC有两种主要的方法:传统的XML方式和Java Servlet方式。这里会穿插讲解,以便较好的比较两种方式,但基本实现原理都是差不多的。
1.配置DispatcherServlet
DispatcherServlet是SpringMVC的核心。在这里请求互第一次接触到框架,它要负责将请求路由到其它的组件中。
下面是一个Servlet容器:
package com.spittr.config;
import org.springframework.web.servlet.support.AbstractAnnotationConfigDispatcherServletInitializer;
public class SpittrWebAppInitializer extends AbstractAnnotationConfigDispatcherServletInitializer {
@Override
protected Class<?>[] getRootConfigClasses() {
return new Class<?>[] { RootConfig.class};
}
@Override
protected Class<?>[] getServletConfigClasses() {
return new Class<?>[] {WebConfig.class};
}
@Override
protected String[] getServletMappings() {
return new String[] {"/"};
}
}
getServletMapping()将一个或多个路径映射到DispatcherServlet上。在本例中,它映射的是“/”,表示它会是应用默认的Servlet,它会处理进入应用的所有请求。
package com.spittr.config;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.ComponentScan.Filter;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.FilterType;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
@Configuration
@ComponentScan(basePackages= {"com.spittr.*"},excludeFilters= {@Filter(type=FilterType.ANNOTATION,value=EnableWebMvc.class)})
public class RootConfig {
}
package com.spittr.config;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.ViewResolver;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
import org.springframework.web.servlet.view.InternalResourceViewResolver;
@Configuration
@EnableWebMvc
@ComponentScan("com.spittr.*")
public class WebConfig{
@Bean
public ViewResolver viewResolver() {
InternalResourceViewResolver resolver=new InternalResourceViewResolver();
resolver.setPrefix("/WEB-INF/views/");
resolver.setSuffix(".jsp");
resolver.setExposeContextBeansAsAttributes(true);
return resolver;
}
}
同样,我们也可以在web.xml中进行配置:
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns="http://java.sun.com/xml/ns/javaee"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
id="WebApp_ID" version="3.0">
<servlet>
<servlet-name>springDispatcherServlet</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<!-- 配置DispatcjerServlet的一个初始化参数:配置SpringMVC配置文件的位置和名称 -->
<!-- 实际上也可以不通过contextConfigLocation来配置SpringMVC的配置文件,而使用默认的
默认的配置文件为:/WEB-INF/<servlet-name>-servlet.xml
-->
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:springmvc.xml</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>springDispatcherServlet</servlet-name>
<url-pattern>/</url-pattern>
</servlet
<?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"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:c="http://www.springframework.org/schema/c"
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
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.3.xsd">
<context:component-scan base-package="com.mvc.*"></context:component-scan>
<!-- 配置视图解析器 -->
<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<property name="prefix" value="/"></property>
<property name="suffix" value=""></property>
</bean>
</beans>
2.编写基本的控制器
这是SpringMVC中最重要的部分。
无论是哪种方式配置的,编写控制器的部分都是相同的。
package com.spittr.config;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
@Controller
public class HomeController {
@RequestMapping("/home")
public String home() {
System.out.println("home...");
return "home";
}
}