纯java配置SpringMVC

一般情况下，我们会在web.xml下配置好Spring和SpringMVC，并指定好它们的配置文件

是最常用的也是最方便的方法

例如：

web.xml

<!-- The definition of the Root Spring Container shared by all Servlets and Filters -->
    <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>/WEB-INF/spring/root-context.xml</param-value>
    </context-param>

    <!-- Creates the Spring Container shared by all Servlets and Filters -->
    <listener>
        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
    </listener>

    <!-- Processes application requests -->
    <servlet>
        <servlet-name>appServlet</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>/WEB-INF/spring/appServlet/servlet-context.xml</param-value>
        </init-param>
        <load-on-startup></load-on-startup>
    </servlet>

    <servlet-mapping>
        <servlet-name>appServlet</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>

今天介绍的是纯java配置，不基于xml，

web.xml中一句代码都不用写。

文件目录：

1.Spring容器的配置文件

package com.mvc.config;

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

@Configuration //标识是配置文件
@ComponentScan("com.mvc.server") //指定自动扫描的包
public class RootConfig {

    //在这里可以配置任何的bean，是基于Spring容器的

}

2.SpringMVC容器的配置文件

package com.mvc.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.DefaultServletHandlerConfigurer;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;
import org.springframework.web.servlet.view.InternalResourceViewResolver;

@Configuration
@EnableWebMvc //表示这个类是SpringMVC的配置文件
@ComponentScan("com.mvc.action")//注意扫描的包
public class WebConfig  extends WebMvcConfigurerAdapter{

    @Bean
    public ViewResolver viewResolver(){
　　　　 //配置视图解析器
        InternalResourceViewResolver resolver = new InternalResourceViewResolver();
        resolver.setPrefix("/WEB-INF/views/");
        resolver.setSuffix(".jsp");
        resolver.setExposeContextBeansAsAttributes(true);
        return resolver;

    }

    @Override
    public void configureDefaultServletHandling(
　　　　　　
            DefaultServletHandlerConfigurer configurer){
        //配置静态资源的处理
        configurer.enable();

    }

}

3.配置自定义的DispatcherServlet，在tomcat启动的时候，会找到这个类，并自动加载它，所以web.xml中不用再写任何有关Spring配置的代码

package com.mvc.config;

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

public class MyDispatcherServlet
    extends AbstractAnnotationConfigDispatcherServletInitializer{

    @Override
    protected Class<?>[] getRootConfigClasses() {
        return new Class<?>[]{RootConfig.class};//加载Spring的配置类
    }

    @Override
    protected Class<?>[] getServletConfigClasses() {
        return new Class<?>[]{WebConfig.class};加载SpringMVC的配置类
    }

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

}

以上，Spring和SpringMVC的配置文件就写好了

4.下面编写控制器，这里的代码就是平时写的类型

package com.mvc.action;

import java.util.Map;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;

import com.mvc.server.PersonServer;

@Controller
public class MyController {

    @Autowired
    private PersonServer p;
    public MyController(){

        System.out.println("MyController...");
    }

    @RequestMapping("test")
    public String test(Map map){

        map.put("p", p.getPerson());

        System.out.println("test...");

        return "home";
    }
}

5.编写服务层

package com.mvc.server;

import org.springframework.stereotype.Service;

import com.mvc.entity.Person;

@Service
public class PersonServer {
    public PersonServer(){
        System.out.println("PersonServer..");

    }

    public Person getPerson(){

        return new Person("aaa",);
    }
}

6.实体类

package com.mvc.entity;

public class Person {

    public Person(){}
    public Person(String name, Integer age) {
        this.name = name;
        this.age = age;
    }
    private String name;
    private Integer age;
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public Integer getAge() {
        return age;
    }
    public void setAge(Integer age) {
        this.age = age;
    }
    @Override
    public String toString() {
        return "Person [name=" + name + ", age=" + age + "]";
    }

}

配置好后，启动tomcat，就可以正常访问了。

需要注意的是WebConfig.java、RootConfig.java、MyDispatcherServlet.java这三个配置类，其他的没什么区别