더블리의 12층

maven에 새 jar를 추가하고 application을 실행해보니 아래와 같은 메세지가 나온다.

오류메세지

:A child container failed during start  
[java.util.concurrent.ExecutionException:](java.util.concurrent.ExecutionException:) [org.apache.catalina.LifecycleException:](org.apache.catalina.LifecycleException:) Failed to start component \[StandardEngine\[Tomcat\].StandardHost\[localhost\].StandardContext\[\]\]  
at [java.util.concurrent.FutureTask.report(FutureTask.java:122)](java.util.concurrent.FutureTask.report(FutureTask.java:122)) ~\[?:1.8.0\_77\]  
at [java.util.concurrent.FutureTask.get(FutureTask.java:192)](java.util.concurrent.FutureTask.get(FutureTask.java:192)) ~\[?:1.8.0\_77\]  
at [org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:911)](org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:911)) \[[tomcat-embed-core-8.5.5.jar:8.5.5\]](tomcat-embed-core-8.5.5.jar:8.5.5])  
at [org.apache.catalina.core.StandardHost.startInternal(StandardHost.java:890)](org.apache.catalina.core.StandardHost.startInternal(StandardHost.java:890)) \[[tomcat-embed-core-8.5.5.jar:8.5.5\]](tomcat-embed-core-8.5.5.jar:8.5.5])  
at [org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)](org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)) \[[tomcat-embed-core-8.5.5.jar:8.5.5\]](tomcat-embed-core-8.5.5.jar:8.5.5])  
at [org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1403)](org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1403)) \[[tomcat-embed-core-8.5.5.jar:8.5.5\]](tomcat-embed-core-8.5.5.jar:8.5.5])  
at [org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1393)](org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1393)) \[[tomcat-embed-core-8.5.5.jar:8.5.5\]](tomcat-embed-core-8.5.5.jar:8.5.5])  
at [java.util.concurrent.FutureTask.run(FutureTask.java:266)](java.util.concurrent.FutureTask.run(FutureTask.java:266)) \[?:1.8.0\_77\]  
at [java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)](java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)) \[?:1.8.0\_77\]  
at [java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)](java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)) \[?:1.8.0\_77\]  
at [java.lang.Thread.run(Thread.java:745)](java.lang.Thread.run(Thread.java:745)) \[?:1.8.0\_77\]  
Caused by: [org.apache.catalina.LifecycleException:](org.apache.catalina.LifecycleException:) Failed to start component \[StandardEngine\[Tomcat\].StandardHost\[localhost\].StandardContext\[\]\]  
at [org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:167)](org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:167)) ~\[[tomcat-embed-core-8.5.5.jar:8.5.5\]](tomcat-embed-core-8.5.5.jar:8.5.5])  
... 6 more  
Caused by: [org.apache.catalina.LifecycleException:](org.apache.catalina.LifecycleException:) Failed to start component \[Pipeline\[StandardEngine\[Tomcat\].StandardHost\[localhost\].StandardContext\[\]\]\]  
at [org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:167)](org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:167)) ~\[[tomcat-embed-core-8.5.5.jar:8.5.5\]](tomcat-embed-core-8.5.5.jar:8.5.5])  
at [org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5099)](org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5099)) ~\[[tomcat-embed-core-8.5.5.jar:8.5.5\]](tomcat-embed-core-8.5.5.jar:8.5.5])  

해결방법

검색해보니 servlet-api.jar를 exclude하라는 말이 많이 나왔는데
나의 경우 아래 설정을 pom에 추가하니 실행 성공하였다.

<dependency>
    <groupId>javax.servlet</groupId>
    <artifactId>servlet-api</artifactId>
    <version>2.5</version>
    <scope>provided</scope>
</dependency>

provided 는 무엇을 의미하는지?

This scope is used to mark dependencies that should be provided at runtime by JDK or a container, hence the name.

A good use case for this scope would be a web application deployed in some container, where the container already provides some libraries itself.
컨테이너에서 deploy도는 어플리케이션에서 컨테이너는 이미 자체적인 라이브러리를 제공한다.

For example, a web server that already provides the Servlet API at runtime, thus in our project, those dependencies can be defined with the provided scope:
런타임에 의존성을 가지지 않고 컴파일/테스트단계에서만 제공되는 dependency.

<dependency>
    <groupId>javax.servlet</groupId>
    <artifactId>servlet-api</artifactId>
    <version>2.5</version>
    <scope>provided</scope>
</dependency>

The provided dependencies are available only at compile-time and in the test classpath of the project; what's more, they aren't transitive.

라이브러리 의존성을 피하기 위한 방법이리라.

spring boot AOP 구현하기.
Aop를 잘 모르지만

• Http 요청이 왔을때 끼어들어 요청에 대한 권한이 있는지 체크하기 위한 AOP를 개발하려한다.
  : http요청이 왔을때 실제 응답을 주기전에 권한을 체크하고 권한이 있으면 계속 진행하도록 해주고, 권한이 없으면 진행을 막는다.
• 더불어 특정 controller에는 권한체크를 하지 않고, http request로 온 header안에 정보를 parameter로 전달하려한다.

1. pom.xml

   <dependency> 
   <groupId>org.springframework.boot</groupId> 
   <artifactId>spring-boot-starter-aop</artifactId>
   </dependency>

2. AopConfig.java
   @Around 이노테이션으로 requestMapping으로 들어오는 요청에 대해서 AOP를 적용할것임을 명시.
   특정 controller 접근시에는 parameter를 넘겨주도록했음.
   주석 참고.

@Configuration
@Aspect
@EnableAspectJAutoProxy() 
public class AopConfig { 
    ...
    @Around("@annotation(requestMapping)") 
    public final Object checkPermission(final ProceedingJoinPoint pjp
                                      , final RequestMapping requestMapping){
        .... 
        //권한을 체크하는 함수에서 true값을 return해주면 계속해서 진행 
        if (permission.check(pjp, requestMapping, httpServletRequest)) { 
            return pjp.proceed();
        } 

        ....
        String email = .... ;
        //특정 controller접근시에는 권한체크는 하지 않고 파라미터만 전달하여 계속 진행
        if (pjp.getSignature().toString().contains("com.xxx.xxx.controller.xxx")) {
            return pjp.proceed(new Object\[\]{email});
        } 
        ... 


        //권한 없는 경우 null을 return하여 계속해서 진행할 수 없음. 
        return null; 
        } 
 }

참고.
proceedjointpoint로 parameter를 넘겨줄때는 넘겨준 parameter와 동일한 명칭, 순서로 받아야한다.

@ResponseBody 
@RequestMapping(method = RequestMethod.GET, value = "/user") 
public LoginUser getLoginEmail(final String email) { 
    LoginUser loginUser = new LoginUser(); 
    loginUser.setEmail(email);
    return loginUser;
}