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准备工作: 创建空白web app并添加spring mvc依赖

配置Spring MVC

继承了AbstractAnnotationConfigDispatcherServletInitializer的类会自动用于配置DispatcherServlet和Spring application context.

从Servlet3.0开始, web容器在classpath下寻找实现了javax.servlet.ServletContainerInitlializer接口的类, 如果找到了这样的类, 就用于配置servlet容器.

Spring提供了一个叫做SpringServletContainerInitializer的实现, 这个类会寻找WebApplicationInitlializer的实现并把配置托管给它. Spring3.2提供了叫做AbstractAnnotationConfigDispatcherServletInitializer的实现. 我们的配置类继承了这个对象所以会被作为初始化配置对象.

getServletMappings()方法返回一个或多个DispatcherServlet被映射的路径, /表示app的默认servlet, 它将处理所有请求.

package com.qiudeqing.config;

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

/**
 * Created by qiudeqing on 16/10/18.
 */
public class WebAppInitializer extends AbstractAnnotationConfigDispatcherServletInitializer {

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

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

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

WebConfig.java

package com.qiudeqing.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.InternalResourceView;
import org.springframework.web.servlet.view.InternalResourceViewResolver;

/**
 * Created by qiudeqing on 16/10/18.
 */
@Configuration
@EnableWebMvc
@ComponentScan("com.qiudeqing.web")
public class WebConfig extends WebMvcConfigurerAdapter {

    @Bean
    public ViewResolver viewResolver() {
        InternalResourceViewResolver resolver = new InternalResourceViewResolver();
        resolver.setPrefix("/WEB-INF/views/");
        resolver.setSuffix(".jsp");
        resolver.setExposeContextBeansAsAttributes(true);
        return resolver;
    }

    @Override
    public void configureDefaultServletHandling(DefaultServletHandlerConfigurer configurer) {
        configurer.enable();
    }
}

WebConfig继承WebMvcConfigurerAdapter并重写configureDefaultServletHandling()方法, 调用DefaultServletHandlerConfigurer的enable()方法. DispatcherServlet将我们没有处理的请求转发到静态资源.

RootConfig.java

package com.qiudeqing.config;

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

/**
 * Created by qiudeqing on 16/10/18.
 */
@Configuration
@ComponentScan(basePackages = {"com.qiudeqing"},
        excludeFilters = {
                @ComponentScan.Filter(type = FilterType.ANNOTATION, value = EnableWebMvc.class)
        }
)
public class RootConfig {
}

5.3 接受请求参数

Spring支持以下方式传递参数：