WebConfig类

 package com.ssm.yjblogs.config;

 import java.util.ArrayList;
 import java.util.List;
 import java.util.concurrent.Executor;

 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.ComponentScan;
 import org.springframework.context.annotation.ComponentScan.Filter;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.context.annotation.FilterType;
 import org.springframework.http.MediaType;
 import org.springframework.http.converter.json.MappingJackson2HttpMessageConverter;
 import org.springframework.scheduling.annotation.AsyncConfigurerSupport;
 import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor;
 import org.springframework.stereotype.Controller;
 import org.springframework.web.servlet.HandlerAdapter;
 import org.springframework.web.servlet.ViewResolver;
 import org.springframework.web.servlet.config.annotation.EnableWebMvc;
 import org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter;
 import org.springframework.web.servlet.view.InternalResourceViewResolver;

 @Configuration
 //定义Spring MVC扫描的包
 @ComponentScan(value="com.*", includeFilters= {@Filter(type = FilterType.ANNOTATION, value = Controller.class)})
 //启动Spring MVC配置 P389
 @EnableWebMvc
 //使用@EnableAsync表明支持异步调用，而我们重写了抽象类AsyncConfigurerSupport的getAsyncExecutor方法
 //它是获取一个任务池，当在Spring环境中遇到注解@Async就会启动这个任务池的一条线程去运行对应的方法，这样便能执行异步了。
 //@EnableAsync
 public class WebConfig extends AsyncConfigurerSupport { 

     /***
      * 通过注解 @Bean 初始化视图解析器
      * @return ViewResolver 视图解析器
      */
     @Bean(name="internalResourceViewResolver")
     public ViewResolver initViewResolver() {
         InternalResourceViewResolver viewResolver =new InternalResourceViewResolver();
         //设置前缀和后缀，这样就能获取由控制器返回的视图逻辑名，进而找到对应的JSP文件  P436
         viewResolver.setPrefix("/WEB-INF/jsp/");//前缀
         viewResolver.setSuffix(".jsp");//后缀
         return viewResolver;
     }

     /**
      * 初始化RequestMappingHandlerAdapter，并加载Http的Json转换器
      * @return  RequestMappingHandlerAdapter 对象
      */
     //注解@ResponseBody将标记SpringMVC，将响应结果转变为JSON，这样在控制器返回结果后，在处理器内转变为JSON  P453
     @Bean(name="requestMappingHandlerAdapter")
     public HandlerAdapter initRequestMappingHandlerAdapter() {
         //创建RequestMappingHandlerAdapter适配器
         RequestMappingHandlerAdapter rmhd = new RequestMappingHandlerAdapter();
         //HTTP JSON转换器
         MappingJackson2HttpMessageConverter  jsonConverter
             = new MappingJackson2HttpMessageConverter();
         //MappingJackson2HttpMessageConverter接收JSON类型消息的转换
         MediaType mediaType = MediaType.APPLICATION_JSON_UTF8;
         List<MediaType> mediaTypes = new ArrayList<MediaType>();
         mediaTypes.add(mediaType);
         //加入转换器的支持类型
         jsonConverter.setSupportedMediaTypes(mediaTypes);
         //往适配器加入json转换器
         rmhd.getMessageConverters().add(jsonConverter);
         return rmhd;
     }

 //    @Override
 //    public Executor getAsyncExecutor() {
 //        ThreadPoolTaskExecutor taskExecutor = new ThreadPoolTaskExecutor();
 //        taskExecutor.setCorePoolSize(5);
 //        taskExecutor.setMaxPoolSize(10);
 //        taskExecutor.setQueueCapacity(200);
 //        taskExecutor.initialize();
 //        return taskExecutor;
 //    }
 }

无行号版本：

package com.ssm.yjblogs.config;

import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.Executor;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.ComponentScan.Filter;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.FilterType;
import org.springframework.http.MediaType;
import org.springframework.http.converter.json.MappingJackson2HttpMessageConverter;
import org.springframework.scheduling.annotation.AsyncConfigurerSupport;
import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor;
import org.springframework.stereotype.Controller;
import org.springframework.web.servlet.HandlerAdapter;
import org.springframework.web.servlet.ViewResolver;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
import org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter;
import org.springframework.web.servlet.view.InternalResourceViewResolver;

@Configuration
//定义Spring MVC扫描的包
@ComponentScan(value="com.*", includeFilters= {@Filter(type = FilterType.ANNOTATION, value = Controller.class)})
//启动Spring MVC配置 P389
@EnableWebMvc
//使用@EnableAsync表明支持异步调用，而我们重写了抽象类AsyncConfigurerSupport的getAsyncExecutor方法
//它是获取一个任务池，当在Spring环境中遇到注解@Async就会启动这个任务池的一条线程去运行对应的方法，这样便能执行异步了。
//@EnableAsync
public class WebConfig extends AsyncConfigurerSupport { 

    /***
     * 通过注解 @Bean 初始化视图解析器
     * @return ViewResolver 视图解析器
     */
    @Bean(name="internalResourceViewResolver")
    public ViewResolver initViewResolver() {
        InternalResourceViewResolver viewResolver =new InternalResourceViewResolver();
        //设置前缀和后缀，这样就能获取由控制器返回的视图逻辑名，进而找到对应的JSP文件  P436
        viewResolver.setPrefix("/WEB-INF/jsp/");//前缀
        viewResolver.setSuffix(".jsp");//后缀
        return viewResolver;
    }

    /**
     * 初始化RequestMappingHandlerAdapter，并加载Http的Json转换器
     * @return  RequestMappingHandlerAdapter 对象
     */
    //注解@ResponseBody将标记SpringMVC，将响应结果转变为JSON，这样在控制器返回结果后，在处理器内转变为JSON  P453
    @Bean(name="requestMappingHandlerAdapter")
    public HandlerAdapter initRequestMappingHandlerAdapter() {
        //创建RequestMappingHandlerAdapter适配器
        RequestMappingHandlerAdapter rmhd = new RequestMappingHandlerAdapter();
        //HTTP JSON转换器
        MappingJackson2HttpMessageConverter  jsonConverter
            = new MappingJackson2HttpMessageConverter();
        //MappingJackson2HttpMessageConverter接收JSON类型消息的转换
        MediaType mediaType = MediaType.APPLICATION_JSON_UTF8;
        List<MediaType> mediaTypes = new ArrayList<MediaType>();
        mediaTypes.add(mediaType);
        //加入转换器的支持类型
        jsonConverter.setSupportedMediaTypes(mediaTypes);
        //往适配器加入json转换器
        rmhd.getMessageConverters().add(jsonConverter);
        return rmhd;
    }

//    @Override
//    public Executor getAsyncExecutor() {
//        ThreadPoolTaskExecutor taskExecutor = new ThreadPoolTaskExecutor();
//        taskExecutor.setCorePoolSize(5);
//        taskExecutor.setMaxPoolSize(10);
//        taskExecutor.setQueueCapacity(200);
//        taskExecutor.initialize();
//        return taskExecutor;
//    }
}