修改登录接口，返回json，补充V3.0beta接口文档

src/main/java/com/fjy/spring/interceptor/WebAppConfig.java

@@ -5,7 +5,7 @@ import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
 import org.springframework.web.servlet.config.annotation.ResourceHandlerRegistry;
 import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
 
-@Configuration
+//@Configuration
 public class WebAppConfig implements WebMvcConfigurer {
 
     /**