springboot2如何禁用自带tomcat的session功能

来源：jb51　　时间：2021/11/9 15:50:52　　对本文有异议

禁用自带tomcat的session功能

微服务下的各个服务都是无状态的，所以这个时候tomcat的session管理功能是多余的，即时不用，也会消耗性能，关闭后tomcat的性能会有提升，但是springboot提供的tomcat没有配置选项可以直接关闭，研究了一下，tomcat默认的session管理器名字叫：StandardManager，查看tomcat加载源码发现，如果context中没有Manager的时候，直接new StandardManager()，源码片段如下：

               Manager contextManager = null;
                Manager manager = getManager();
                if (manager == null) {
                    if (log.isDebugEnabled()) {
                        log.debug(sm.getString("standardContext.cluster.noManager",
                                Boolean.valueOf((getCluster() != null)),
                                Boolean.valueOf(distributable)));
                    }
                    if ((getCluster() != null) && distributable) {
                        try {
                            contextManager = getCluster().createManager(getName());
                        } catch (Exception ex) {
                            log.error(sm.getString("standardContext.cluster.managerError"), ex);
                            ok = false;
                        }
                    } else {
                        contextManager = new StandardManager();
                    }
                }
 
                // Configure default manager if none was specified
                if (contextManager != null) {
                    if (log.isDebugEnabled()) {
                        log.debug(sm.getString("standardContext.manager",
                                contextManager.getClass().getName()));
                    }
                    setManager(contextManager);
                }

为了不让tomcat去new自己的管理器，必须让第二行的getManager()获取到对象，所以就可以从这里入手解决，我的解决办法如下：自定义一个tomcat工厂，继承原来的工厂，context中加入自己写的manager

@Component
public class TomcatServletWebServerFactorySelf extends TomcatServletWebServerFactory { 
    protected void postProcessContext(Context context) {
        context.setManager(new NoSessionManager());
    }
}

public class NoSessionManager extends ManagerBase implements Lifecycle { 
    @Override
    protected synchronized void startInternal() throws LifecycleException {
        super.startInternal();
        try {
            load();
        } catch (Throwable t) {
            ExceptionUtils.handleThrowable(t);
            t.printStackTrace();
        }
        setState(LifecycleState.STARTING);
    }
 
    @Override
    protected synchronized void stopInternal() throws LifecycleException {
        setState(LifecycleState.STOPPING);
        try {
            unload();
        } catch (Throwable t) {
            ExceptionUtils.handleThrowable(t);
            t.printStackTrace();
        }
        super.stopInternal();
    }
 
    @Override
    public void load() throws ClassNotFoundException, IOException {
        log.info("HttpSession 已经关闭,若开启请配置：seeyon.tomcat.disableSession=false");
    }
 
    @Override
    public void unload() throws IOException {}
    @Override
    public Session createSession(String sessionId) {
        return null;
    }
 
    @Override
    public Session createEmptySession() {
        return null;
    }
 
    @Override
    public void add(Session session) {}
    @Override
    public Session findSession(String id) throws IOException {
        return null;
    }
    @Override
    public Session[] findSessions(){
        return null;
    }
    @Override
    public void processExpires() {}
}

两个类解决问题，这样通过request获取session就是空了，tomcat摆脱session这层处理性能有所提升。

禁用内置Tomcat的不安全请求方法

起因：安全组针对接口测试提出的要求，需要关闭不安全的请求方法，例如put、delete等方法，防止服务端资源被恶意篡改。

用过springMvc都知道可以使用@PostMapping、@GetMapping等这种注解限定单个接口方法类型，或者是在@RequestMapping中指定method属性。这种方式比较麻烦，那么有没有比较通用的方法，通过查阅相关资料，答案是肯定的。

tomcat传统形式通过配置web.xml达到禁止不安全的http方法

    <security-constraint>  
       <web-resource-collection>  
          <url-pattern>/*</url-pattern>  
          <http-method>PUT</http-method>  
       <http-method>DELETE</http-method>  
       <http-method>HEAD</http-method>  
       <http-method>OPTIONS</http-method>  
       <http-method>TRACE</http-method>  
       </web-resource-collection>  
       <auth-constraint>  
       </auth-constraint>  
    </security-constraint>  
    <login-config>  
      <auth-method>BASIC</auth-method>  
    </login-config>

Spring boot使用内置tomcat，2.0版本以前使用如下形式

@Bean  
public EmbeddedServletContainerFactory servletContainer() {  
    TomcatEmbeddedServletContainerFactory tomcat = new TomcatEmbeddedServletContainerFactory() {// 1  
        protected void postProcessContext(Context context) {  
            SecurityConstraint securityConstraint = new SecurityConstraint();  
            securityConstraint.setUserConstraint("CONFIDENTIAL");  
            SecurityCollection collection = new SecurityCollection();  
            collection.addPattern("/*");  
            collection.addMethod("HEAD");  
            collection.addMethod("PUT");  
            collection.addMethod("DELETE");  
            collection.addMethod("OPTIONS");  
            collection.addMethod("TRACE");  
            collection.addMethod("COPY");  
            collection.addMethod("SEARCH");  
            collection.addMethod("PROPFIND");  
            securityConstraint.addCollection(collection);  
            context.addConstraint(securityConstraint);  
        }  
    };

2.0版本使用以下形式

@Bean
public ConfigurableServletWebServerFactory configurableServletWebServerFactory() {
    TomcatServletWebServerFactory factory = new TomcatServletWebServerFactory();
    factory.addContextCustomizers(context -> {
        SecurityConstraint securityConstraint = new SecurityConstraint();
        securityConstraint.setUserConstraint("CONFIDENTIAL");
        SecurityCollection collection = new SecurityCollection();
        collection.addPattern("/*");
        collection.addMethod("HEAD");
        collection.addMethod("PUT");
        collection.addMethod("DELETE");
        collection.addMethod("OPTIONS");
        collection.addMethod("TRACE");
        collection.addMethod("COPY");
        collection.addMethod("SEARCH");
        collection.addMethod("PROPFIND");
        securityConstraint.addCollection(collection);
        context.addConstraint(securityConstraint);
    });
    return factory;
}