手写SpringBoot框架

不念不忘少年蓝@ 2022-03-19 03:14 241阅读 0赞

### 1.Maven依赖 ###

<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/maven-v4_0_0.xsd">
    	<modelVersion>4.0.0</modelVersion>
    	<groupId>com.weichai</groupId>
    	<artifactId>SpringBoot_Write</artifactId>
    	<version>0.0.1-SNAPSHOT</version>
    	<name>SpringBoot_Write Maven Webapp</name>
    	<url>http://maven.apache.org</url>
    	<dependencies>
    
    		
    		<dependency>
    			<groupId>org.apache.tomcat.embed</groupId>
    			<artifactId>tomcat-embed-core</artifactId>
    			<version>9.0.10</version>
    		</dependency>
    
    		
    		<dependency>
    			<groupId>org.apache.tomcat</groupId>
    			<artifactId>tomcat-jasper</artifactId>
    			<version>9.0.10</version>
    		</dependency>
    
    		<dependency>
    			<groupId>org.springframework</groupId>
    			<artifactId>spring-webmvc</artifactId>
    			<version>5.1.0.RELEASE</version>
    			<scope>compile</scope>
    		</dependency>
    
    		<dependency>
    			<groupId>org.springframework</groupId>
    			<artifactId>spring-web</artifactId>
    			<version>5.1.0.RELEASE</version>
    			<scope>compile</scope>
    		</dependency>
    
    		<dependency>
    			<groupId>junit</groupId>
    			<artifactId>junit</artifactId>
    			<version>3.8.1</version>
    			<scope>test</scope>
    		</dependency>
    	</dependencies>
    	<build>
    		<finalName>SpringBoot_Write</finalName>
    	</build>
    </project>

### 2.创建tomcat容器启动类 ###

package com.weichai.springboot;
    
    import java.io.File;
    
    import javax.servlet.ServletException;
    
    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;
    
    /**
        *    手写SpringBoot App启动类
     * @author linhaiy
     * @date 2019.02.13
     */
    public class App {
    
    	public final static int PORT = 8090;
    	
    	public static void main(String[] args) throws ServletException, LifecycleException {
    		// TODO Auto-generated method stub
    		start();
    	}
    
    	public static void start() throws ServletException, LifecycleException {
    		// 创建Tomcat容器
    		Tomcat tomcatServer = new Tomcat();
    		// 端口号设置
    		tomcatServer.setPort(PORT);
    		// 读取项目路径 加载静态资源
    		StandardContext ctx = (StandardContext) tomcatServer.addWebapp("/", new File("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();
    	}
    }

### 3.根配置类 ###

package com.weichai.springboot.config;
    
    import org.springframework.context.annotation.ComponentScan;
    import org.springframework.context.annotation.Configuration;
    
    /**
        *   根配置
     * @author linhaiy
     * @date 2019.02.13
     */
    @Configuration
    @ComponentScan("com.weichai.springboot")
    public class RootConfig {
    
    }

### 4.SpringMVC配置信息加载类 ###

package com.weichai.springboot.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.config.annotation.WebMvcConfigurerAdapter;
    import org.springframework.web.servlet.view.InternalResourceViewResolver;
    
    /**
     * SpringMVC配置信息
     * @author linhaiy
     * @date 2019.02.13
     */
    
    @Configuration
    @EnableWebMvc
    @ComponentScan(basePackages = {"com.weichai.springboot.controller"})
    public class WebConfig extends WebMvcConfigurerAdapter {
    
    	/**
    	 * springboot 整合jsp 最好是war
    	 * InternalResourceViewResolver
    	    *     创建SpringMVC视图解析器
    	 * @return
    	 */
    	@Bean
    	public ViewResolver viewResolver() {
    		InternalResourceViewResolver viewResolver = new InternalResourceViewResolver();
    		viewResolver.setPrefix("/WEB-INF/views/");
    		viewResolver.setSuffix(".jsp");
    		// 可以在JSP页面中通过 ${} EL表达式访问beans
    		viewResolver.setExposeContextBeansAsAttributes(true);
    		return viewResolver;
    	}
    }

### 5.SpringMVC DispatcherServlet加载类 ###

package com.weichai.springboot.config;
    
    import org.springframework.web.servlet.support.AbstractAnnotationConfigDispatcherServletInitializer;
    
    /**
        *    加载SpringMVC DispatcherServlet
     * @author linhaiy
     *
     */
    public class SpringWebAppInitializer extends AbstractAnnotationConfigDispatcherServletInitializer {
    
    	/**
    	    *   加载根配置信息 spring核心
    	 */
    	@Override
    	protected Class<?>[] getRootConfigClasses() {
    		// TODO Auto-generated method stub
    		return new Class<?>[] {RootConfig.class};
    	}
    
    	/**
    	 * springmvc 加载 配置信息
    	 */
    	@Override
    	protected Class<?>[] getServletConfigClasses() {
    		// TODO Auto-generated method stub
    		return new Class [] {WebConfig.class};
    	}
    
    	/**
    	 * SpringMVC 拦截url映射 拦截所有请求
    	 */
    	@Override
    	protected String[] getServletMappings() {
    		// TODO Auto-generated method stub
    		return new String[] {"/"};
    	}
    
    }

### 6.业务逻辑层 ###

package com.weichai.springboot.service;
    
    import org.springframework.stereotype.Service;
    
    @Service
    public class UserService {
    
    	public String index() {
    		return "springboot 2.0  我正在加载UserService";
    	}
    }

### 7.控制层测试 ###

package com.weichai.springboot.controller;
    
    import org.springframework.stereotype.Controller;
    import org.springframework.web.bind.annotation.RequestMapping;
    
    /**
        *     跳转页面
     * @author linhaiy
     * @date 2019.02.13
     */
    @Controller
    public class UserController {
    
    	@RequestMapping("/pageIndex")
    	public String pageIndex() {
    		return "pageIndex";
    	}
    }

package com.weichai.springboot.controller;
    
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RestController;
    
    import com.weichai.springboot.service.UserService;
    
    @RestController
    public class IndexController {
    
    	@Autowired
    	private UserService userService;
    	
    	@RequestMapping(value = "/index", produces = "text/html;charset=UTF-8")
    	public String index() {
    		return userService.index();
    	}
    }

### 8.测试映射页面 ###

<%@ 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>手写SpringBoot</title>
    </head>
    <body>
    
    	<h1>纯手写SpringBoot框架，感谢支持海哥!</h1>
    
    </body>
    </html>