spring-boot的web开发_springboot启动报错instance must be started before call

Web开发的自动配置类：
org.springframework.boot.autoconfigure.web.WebMvcAutoConfiguration

1. 自动配置的ViewResolver

视图的配置mvcProperties对象中：
org.springframework.boot.autoconfigure.web.WebMvcProperties.View

2. 自动配置静态资源

2.1. 进入规则为 /

如果进入SpringMVC的规则为/时，Spring Boot的默认静态资源的路径为：

spring.resources.static-locations=
classpath:/META-INF/resources/,classpath:/resources/,classpath:/static/,classpath:/public/

2.2.案例测试

地址 :
https://gitee.com/gaoxinfu/demo-spring-boot/tree/master/demo-spring-boot-example-02

http://localhost:8088/test.jpg

3.自定义消息转换器

详见
https://blog.csdn.net/u014636209/article/details/86410517

4.自定义SpringMVC的配置

有些时候我们需要自已配置SpringMVC而不是采用默认，比如说增加一个拦截器，
这个时候就得通过继承WebMvcConfigurerAdapter然后重写父类中的方法进行扩展。

import java.nio.charset.Charset;
import java.util.List;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.context.annotation.Configuration;
import org.springframework.http.converter.HttpMessageConverter;
import org.springframework.http.converter.StringHttpMessageConverter;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;

@Configuration //申明这是一个配置
public class MySrpingMVCConfig extends WebMvcConfigurerAdapter{

    // 自定义拦截器
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        HandlerInterceptor handlerInterceptor = new HandlerInterceptor() {
            @Override
            public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
                    throws Exception {
                System.out.println("自定义拦截器............");
                return true;
            }
            
            @Override
            public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler,
                    ModelAndView modelAndView) throws Exception {
                
            }
            
            @Override
            public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler,
                    Exception ex) throws Exception {
            }
        };
        registry.addInterceptor(handlerInterceptor).addPathPatterns("/**");
    }

    // 自定义消息转化器的第二种方法
    @Override
    public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
        StringHttpMessageConverter converter  = new StringHttpMessageConverter(Charset.forName("UTF-8"));
        converters.add(converter);
    }
}