利用java類方式配置一個springmvc應用

1，職責

①，參看官網對java配置容器的介紹

https://docs.spring.io/spring/docs/5.1.0.BUILD-SNAPSHOT/spring-framework-reference/web.html#mvc-servlet-context-hierarchy

②，官方推薦，實現父子容器對整個應用進行管理，即根容器掃描service層，和repository層組件，web容器掃描web相關組件如controller，@ControllerAdvice

③，pom.xml

<dependencies>
  	<!-- https://mvnrepository.com/artifact/org.springframework/spring-webmvc -->
	<dependency>
	    <groupId>org.springframework</groupId>
	    <artifactId>spring-webmvc</artifactId>
	    <version>5.0.6.RELEASE</version>
	</dependency>
	<!-- https://mvnrepository.com/artifact/javax.servlet/javax.servlet-api -->
	<dependency>
	    <groupId>javax.servlet</groupId>
	    <artifactId>javax.servlet-api</artifactId>
	    <version>3.0.1</version>
	    <scope>provided</scope>
	</dependency>
	
  	
  </dependencies>
  
  <build>
  	<plugins>
  		<plugin>
  			<groupId>org.apache.maven.plugins</groupId>
  			<artifactId>maven-war-plugin</artifactId>
  			<version>3.2.1</version>
  			<configuration>
  				<failOnMissingWebXml>false</failOnMissingWebXml>
  			</configuration>
  		</plugin>
  	</plugins>
  </build>

2，根容器

import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.ComponentScan.Filter;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.context.annotation.FilterType;

//掃描service層，和repository層組件
@ComponentScan(basePackages="com.spring",
	excludeFilters= {@Filter(type=FilterType.ANNOTATION,classes= {Controller.class,ControllerAdvice.class,ControllerAdvice.class})}
)
public class RootConig {

}

3，web容器

import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.ComponentScan.Filter;
import org.springframework.scheduling.annotation.EnableAsync;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.servlet.config.annotation.DefaultServletHandlerConfigurer;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.ViewControllerRegistry;
import org.springframework.web.servlet.config.annotation.ViewResolverRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;

import com.spring.interceptor.MyInterceptor;

import org.springframework.context.annotation.FilterType;

@ComponentScan(basePackages="com.spring",
	includeFilters= {@Filter(type=FilterType.ANNOTATION,classes= {Controller.class,ControllerAdvice.class})}
,useDefaultFilters=false
)
@EnableWebMvc
public class WebConig implements WebMvcConfigurer{
	
//	配置視圖解析器
	@Override
	public void configureViewResolvers(ViewResolverRegistry registry) {
			registry.jsp();
	}
//	容許靜態資源被訪問
	@Override
	public void configureDefaultServletHandling(DefaultServletHandlerConfigurer configurer) {
		configurer.enable();
	}
	
//	註冊攔截器
	@Override
	public void addInterceptors(InterceptorRegistry registry) {
		registry.addInterceptor(new MyInterceptor());
	}
}

4,攔截器

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.web.servlet.HandlerInterceptor;

public class MyInterceptor implements HandlerInterceptor{
	
	@Override
	public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
			throws Exception {
		System.out.println("我是前置攔截");
		return HandlerInterceptor.super.preHandle(request, response, handler);
	}

}

5，webmvc大管家

import org.springframework.web.servlet.support.AbstractAnnotationConfigDispatcherServletInitializer;

import com.spring.config.RootConig;
import com.spring.config.WebConig;

public class MyWebInitialize extends AbstractAnnotationConfigDispatcherServletInitializer{

	@Override
	protected Class<?>[] getRootConfigClasses() {
		return new Class[] {RootConig.class};
	}

	@Override
	protected Class<?>[] getServletConfigClasses() {
		return new Class[] {WebConig.class};
	}

	@Override
	protected String[] getServletMappings() {
		return new String[] {"/"};
	}

}

6，controller

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;

@Controller
public class HomeController {
	@RequestMapping("/index")
	public String index() {
		
		return "index";
	}

}

7，index.jsp

<%@ 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>
<h1>index page</h1>

<img alt="" src="dm.jpg"/>
</body>
</html>