SpringBoot之SpringMVC自动配置

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一、前言：

• 对于一般应用而言，spring boot对Spring mvc的自动化配置能很好的满足需求了。

二、自动化配置所带来的新特新。

• ContentNegotiatingViewResolver
• BeanNameViewResolver
• 支持多种静态资源
• 支持 HttpMessageConverters（自动注册）：负责处理http请求和响应、解析json或者xml，默认编码UTF-8
• 静态 index.html 支持
• 自定义 Favicon
• 自动使用 ConfigurableWebBindingInitializer

三、增加特性

• If you want to keep Spring Boot MVC features, and you just want to add additional MVC configuration (interceptors, formatters, view controllers etc.) you can add your own @Configuration class of type WebMvcConfigurerAdapter, but without @EnableWebMvc. If you wish to provide custom instances of RequestMappingHandlerMapping, RequestMappingHandlerAdapter or ExceptionHandlerExceptionResolver you can declare a WebMvcRegistrationsAdapter instance providing such components.

• If you want to take complete control of Spring MVC, you can add your own @Configuration annotated with @EnableWebMvc.

增加自定义转换器

• 代码如下

    	import org.springframework.boot.autoconfigure.web.HttpMessageConverters;
    	import org.springframework.context.annotation.*;
    	import org.springframework.http.converter.*;
  
    	@Configuration
    	public class MyConfiguration {
  
    			@Bean
    			public HttpMessageConverters customConverters() {
    					HttpMessageConverter<?> additional = ...
    					HttpMessageConverter<?> another = ...
    					return new HttpMessageConverters(additional, another);
    			}
  
    	}
  

自定义json 序列化和反序列化

• 一般不需要自定义

• @JsonComponent标记的类将会被Spring 自动加载，在进行json的操作时将通过JsonSerializer和JsonDeserializerz 这两个类来实现

• Spring Boot也提供来JsonObjectSerializer and JsonObjectDeserializer b两个操作json的基类便于用户扩展。

    	import java.io.*;
    	import com.fasterxml.jackson.core.*;
    	import com.fasterxml.jackson.databind.*;
    	import org.springframework.boot.jackson.*;
  
    	@JsonComponent
    	public class Example {
  
    			public static class Serializer extends JsonSerializer<SomeObject> {
    					// ...
    			}
  
    			public static class Deserializer extends JsonDeserializer<SomeObject> {
    					// ...
    			}
  
    	}