spring boot 实现配置多个DispatcherServlet最简单方式

传统的web项目，只需要在web.xml里配置多个即可，并且支持多个url-pattern

在spring boot中，我们默认无需配置，系统会自动装配一个，感兴趣的可以看下源码

org.springframework.boot.autoconfigure.web.servlet.DispatcherServletAutoConfiguration

里面有个 DispatcherServletRegistrationBean，关键是这里只能指定一个path，如下的源码截图

如果想要指定多个，我们只能自己写DispatcherServletRegistrationBean这个Bean了，那么系统就不会实例化内置的那个了，如下代码

@Autowired

private WebMvcProperties webMvcProperties;
@Autowired
private MultipartConfigElement multipartConfig;

@Bean @Primary

public DispatcherServletRegistrationBean dispatcherServlet1(DispatcherServlet dispatcherServlet) {
 DispatcherServletRegistrationBean registration = new DispatcherServletRegistrationBean(
   dispatcherServlet, "/*");
 registration.setName("dispatcherServlet1");
 registration.setLoadOnStartup(
   this.webMvcProperties.getServlet().getLoadOnStartup());
 if (this.multipartConfig != null) {
  registration.setMultipartConfig(this.multipartConfig);
 }
 return registration;
}

@Bean

public DispatcherServletRegistrationBean dispatcherServlet2(DispatcherServlet dispatcherServlet) {
 DispatcherServletRegistrationBean registration = new DispatcherServletRegistrationBean(
   dispatcherServlet, "/aaa/*");
 registration.setName("dispatcherServlet2");
 registration.setLoadOnStartup(
   this.webMvcProperties.getServlet().getLoadOnStartup());
 if (this.multipartConfig != null) {
  registration.setMultipartConfig(this.multipartConfig);
 }
 return registration;
}

@Bean

public DispatcherServletRegistrationBean dispatcherServlet3(DispatcherServlet dispatcherServlet) {
 DispatcherServletRegistrationBean registration = new DispatcherServletRegistrationBean(
   dispatcherServlet, "/bbb/*");
 registration.setName("dispatcherServlet3");
 registration.setLoadOnStartup(
   this.webMvcProperties.getServlet().getLoadOnStartup());
 if (this.multipartConfig != null) {
  registration.setMultipartConfig(this.multipartConfig);
 }
 return registration;
}

这样我们参考底层源码，我们做了三个Bean，注意有一个一定要加上@Primary注解，否则启动会有报错。

如果我们系统有一个接口url是/api/test，那么通过/aaa/api/test或者/bbb/api/test也都可以访问了。

不建议的写法、、、

@Bean
 public ServletRegistrationBean apiDispatcherServlet(){
  AnnotationConfigWebApplicationContext applicationContext = new AnnotationConfigWebApplicationContext();
  applicationContext.scan("com.be.edge.asset.web.api");
  DispatcherServlet apiDispatcherServlet = new DispatcherServlet(applicationContext);
  ServletRegistrationBean registrationBean = new ServletRegistrationBean(apiDispatcherServlet);
  registrationBean.addInitParameter("throwExceptionIfNoHandlerFound", "true");
  registrationBean.setLoadOnStartup(1);
  registrationBean.addUrlMappings("/api/*");
  registrationBean.setName("apiDispatcherServlet");
  return registrationBean;
 }
 @Bean
 public ServletRegistrationBean mgmtDispatcherServlet(){
  AnnotationConfigWebApplicationContext applicationContext = new AnnotationConfigWebApplicationContext();
  applicationContext.scan("com.be.edge.asset.web.controller");
  DispatcherServlet apiDispatcherServlet = new DispatcherServlet(applicationContext);
  ServletRegistrationBean registrationBean = new ServletRegistrationBean(apiDispatcherServlet);
  registrationBean.setLoadOnStartup(2);
  registrationBean.addInitParameter("throwExceptionIfNoHandlerFound", "true");
  registrationBean.addUrlMappings("/mgmt/*");
  registrationBean.setName("mngDispatcherServlet");
  return registrationBean;
 }

以上为个人经验，希望能给大家一个参考，也希望大家多多支持我们。如有错误或未考虑完全的地方，望不吝赐教。