spring boot(9)-- spring mvc整合

1、pom 文件

新建项目，pom文件如下：

<?xml version="1.0" encoding="UTF-8"?>
<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>enjoy</groupId>
    <artifactId>springboot_mvc</artifactId>
    <version>1.0-SNAPSHOT</version>

    <dependencies>

        <!--Java语言操作tomcat -->
        <dependency>
            <groupId>org.apache.tomcat.embed</groupId>
            <artifactId>tomcat-embed-core</artifactId>
            <version>8.5.16</version>
        </dependency>

        <!-- tomcat对jsp支持 -->
        <dependency>
            <groupId>org.apache.tomcat</groupId>
            <artifactId>tomcat-jasper</artifactId>
            <version>8.5.16</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-web</artifactId>
            <version>5.0.4.RELEASE</version>
            <scope>compile</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>5.0.4.RELEASE</version>
            <scope>compile</scope>
        </dependency>
    </dependencies>

</project>

2、新增UserService

import org.springframework.stereotype.Service;

@Service
public class UserService {
	public String index() {
		return "springboot 2.0  我正在加载UserService";
	}
}

3、新建RestController

import cn.enjoy.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class IndexController {
	@Autowired
	private UserService userService;

	@RequestMapping(value = "/index", produces = "text/html;charset=UTF-8")
	public String index() {
		return userService.index();
	}

}

一些常用业务类已经准备完毕，接下来就是真正的整合了。

4、常用配置类

4.1、DispatcherServlet

虽然前面有了service,有了controller,但依然没有把这些组建交给spring,对于springmvc来说，有个DispatcherServlet，这是springmvc的前端控制器，以前是配置在web.xml中。只是现在用的是注解。

import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.support.AbstractAnnotationConfigDispatcherServletInitializer;


@Configuration
public class SpringWebAppInitializer extends AbstractAnnotationConfigDispatcherServletInitializer {

	// 加载根配置信息 spring核心
	protected Class<?>[] getRootConfigClasses() {
		return new Class[] { RootConfig.class };
	}

	// springmvc 加载 配置信息
	protected Class<?>[] getServletConfigClasses() {
		return new Class[] { WebConfig.class };
	}

	// springmvc 拦截url映射 拦截所有请求
	protected String[] getServletMappings() {
		return new String[] { "/" };
	}

}

4.2、RootConfig

import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;

@Configuration
@ComponentScan("cn.enjoy")
public class RootConfig {

}

4.3 WebConfig

import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;


@Configuration
@EnableWebMvc
@ComponentScan(basePackages = { "cn.enjoy.controller" })
//public class WebConfig extends WebMvcConfigurerAdapter {
public class WebConfig implements WebMvcConfigurer {


}

5、集成tomcat

import org.apache.catalina.LifecycleException;
import org.apache.catalina.WebResourceRoot;
import org.apache.catalina.core.StandardContext;
import org.apache.catalina.startup.Tomcat;
import org.apache.catalina.webresources.DirResourceSet;
import org.apache.catalina.webresources.StandardRoot;

import javax.servlet.ServletException;
import java.io.File;

public class TomcatApp {

    public static void main(String[] args) throws ServletException, LifecycleException {
        start();
    }

    public static void start() throws ServletException, LifecycleException {

        // 创建Tomcat容器
        Tomcat tomcatServer = new Tomcat();
        // 端口号设置
        tomcatServer.setPort(9090);
        // 读取项目路径 加载静态资源
        StandardContext ctx = (StandardContext) tomcatServer.addWebapp("/", new File("springboot_mvc/src/main").getAbsolutePath());
        // 禁止重新载入
        ctx.setReloadable(false);
        // class文件读取地址
        File additionWebInfClasses = new File("target/classes");
        // 创建WebRoot
        WebResourceRoot resources = new StandardRoot(ctx);
        // tomcat内部读取Class执行
        resources.addPreResources(
                new DirResourceSet(resources, "/WEB-INF/classes", additionWebInfClasses.getAbsolutePath(), "/"));
        tomcatServer.start();
        // 异步等待请求执行
        tomcatServer.getServer().await();

    }
}

6、测试

启动，在地址栏输入：

	http://localhost:9090/index