微人事第一天：spring和springmvc的整合(无需xml)

前面已经介绍过了spring和springmvc的基本配置过程了，可以得知之前的配置是用xml文件进行配置的，这次我们不使用xml文件就使用java来代替xml文件

1.先写pom.xml文件

    4.0.0

    org.example
    javassm
    1.0-SNAPSHOT
    war

    
        
            org.springframework
            spring-webmvc
            5.1.6.RELEASE
        
        
            javax.servlet
            javax.servlet-api
            4.0.0
            provided
        
    

2.SpringConfig文件(相当于配置spring的xml文件)

package org.javaboy.config;

import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.FilterType;
import org.springframework.stereotype.Controller;

//这个文件的作用就是和传统配置spring的xml文件的作用是一样的
@Configuration
//这个注解的作用是包扫描
@ComponentScan(basePackages = "org.javaboy",useDefaultFilters = true,
excludeFilters = {@ComponentScan.Filter(type = FilterType.ANNOTATION,classes = Controller.class)})
public class SpringConfig {

}

这里通过@ComponentScan进行扫描，扫描除了controller的所有类(原理和xml中的原理相同)

3.SpringMvcConfig文件（和配置springmvc的xml文件作用相同）

package org.javaboy.config;

import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.FilterType;
import org.springframework.stereotype.Controller;

//这个类的作用和springmvc的配置类是一样的
@Configuration
//这个注解是包扫描  这里这扫描controller
@ComponentScan(basePackages = "org.javaboy",useDefaultFilters = false,
includeFilters = {@ComponentScan.Filter(type = FilterType.ANNOTATION,classes = Controller.class),
@ComponentScan.Filter(type = FilterType.ANNOTATION,classes = Configuration.class)})
public class SpringMvcConfig {

}

这里@ComponentScan.Filter(type = FilterType.ANNOTATION,classes = Configuration.class)的作用是将SpringConfig加载进来，如果不写spring的配置就加载不进来。

4.webInit文件(目的:将spring和springmvc的配置加载进来)

package org.javaboy.config;


import org.springframework.web.WebApplicationInitializer;
import org.springframework.web.context.support.AnnotationConfigWebApplicationContext;
import org.springframework.web.servlet.DispatcherServlet;

import javax.servlet.ServletException;
import javax.servlet.ServletRegistration;

//这个类用来加载spring和springmvc配置
public class WebInit implements WebApplicationInitializer {

    //当容器启动时这个方法会被触发
    public void onStartup(javax.servlet.ServletContext servletContext) throws ServletException {
        //创建AnnotationConfigWebApplicationContext对象
        AnnotationConfigWebApplicationContext ctx = new AnnotationConfigWebApplicationContext();
        //设置servletContext
        ctx.setServletContext(servletContext);
        //注册springmvc的bean
        ctx.register(SpringMvcConfig.class);
        //在springvc中创建核心控制器
        ServletRegistration.Dynamic springmvc = servletContext.addServlet("springmvc", new DispatcherServlet(ctx));
        //在springmvc中创建映射器
        springmvc.addMapping("/");
        //启动步骤设置为1(最先执行)
        springmvc.setLoadOnStartup(1);

    }
}

上面文件的作用和web.xml文件的作用一模一样，都是要将spring和springmvc的配置类加载进来

5.service类和controller类

package org.javaboy.controller;

import org.javaboy.service.HelloService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class HelloController {

    @Autowired
    private HelloService helloService;

    @GetMapping("/hello")
    public String hello() {
        return helloService.sayHello();
    }
}

package org.javaboy.service;

import org.springframework.stereotype.Service;

@Service
public class HelloService {

    public String sayHello() {
        return "hello javassm!";
    }
}

6.点击启动tomcat
访问路径：http://localhost:8080/javassm_war/hello
显示：