spring

通过命令行读取参数

1. java -jar xxx.jar aaa bbb cccc
   1.1 通过main方法的参数获取
   1.2 或者通过ApplicationArguments注入获取
   
2. java -jar xxx.jar --a1=aaa --b1=bbb
   2.1 可以通过@Value("${a1}"） 获取
   

测试用例

pom文件引入jar包

<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-test</artifactId>
    <version>4.3.2.RELEASE</version>
    <scope>test</scope>
</dependency>
<dependency>
    <groupId>junit</groupId>
    <artifactId>junit</artifactId>
    <version>4.12</version>
    <scope>test</scope>
</dependency>

单元测试编写

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations = {
                        "classpath:beans.xml",
                        "classpath:mybatis.xml"
                    })
@FixMethodOrder(MethodSorters.NAME_ASCENDING)
public class ServiceTest {
   @Resource
   private TrackService trackService;

   @Test
   public void testFindListByReferenceNo(){
       List<TrackEnt> list =  service.findListByReferenceNo("KKon0019998");
       assertEquals(10,list.size());
   }
}

1.1 通过@Before实现测试用例运行前初始化
1.2 通过@After实现测试用例完成后清理
1.3 参考：https://www.jianshu.com/p/83eadf7b352f

Spring MVC

拦截器

1. 执行顺序：filter -> Interceptor -> controller
2. handleInterceptor拦截比filter更加精准，可以到达方法级别
   2.1 preHandle是在进入controller之前执行，postHandle是在返回model渲染视图之前执行，afterCompletion是在request执行完成后执行的
   2.2 拦截配置：

   public class MvcConfig implements WebMvcConfigurer{
       	@Override
       	public void addViewControllers(ViewControllerRegistry registry) {
       		registry.addViewController("/").setViewName("forward:/WEB-INF/views/login.jsp");
       		registry.setOrder(Ordered.HIGHEST_PRECEDENCE);
       	}
       
       	@Override
       	public void addResourceHandlers(ResourceHandlerRegistry registry) {
       		registry.addResourceHandler("/webapp/static/**").addResourceLocations("classpath:/webapp/static/");
       	}
       
           @Override
           public void addInterceptors(InterceptorRegistry registry) {
               registry.addInterceptor(userInterceptor).addPathPatterns("/**").excludePathPatterns("/login/sub.do");
           }
   }
   

   2.3 被拦截后返回错误码

   public class UserInterceptor extends HandlerInterceptorAdapter {
       public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
           PdaResponse pdaResult = new PdaResponse();
           pdaResult.setSuccess(false);
           pdaResult.setCode("-2");
           pdaResult.setMessage("pdaNeedReLogin");
           response.getOutputStream().write(JsonUtl.Object2Json(pdaResult).getBytes());
           response.getOutputStream().close();
           return false;
       }
   }
   

session

1. getSession(boolean create):返回当前request中的HttpSession
   -->如果当前reqeust中的HttpSession为null
   （1）当create为true，就创建一个新的session
   （2）当create为false,返回null
   
2. HttpServletRequest.getSession(ture)等同于HttpServletRequest.getSession()
   
3. session原理图
   
   3.1 注册过滤器代理
   
   3.2 Session过滤器执行流程分析
   
   (1)对请求的HttpServletRequest ，HttpServletResponse 对进行包装
   (2)调用 filterChain.doFilter(strategyRequest, strategyResponse)往后传递
   --> 获得session的话，得到的将会是Spring Session 提供的 HttpServletSession实例
   （3）整个过滤器链执行完后，提交session:wrappedRequest.commitSession();
   3.3 SessionRepositoryFilter$SessionRepositoryRequestWrapper#getSession方法分析
   

    1. S requestedSession = getRequestedSession();
      1.1 List<String> sessionIds = SessionRepositoryFilter.this.httpSessionIdResolver
          						                                .resolveSessionIds(this);
         (1)httpSessionIdResolver分为CookieHttpSessionIdResolver和HeaderHttpSessionIdResolver
            --> 分别从cookie或者头部获取sessionId
      1.2 S session = SessionRepositoryFilter.this.sessionRepository
         							                    .findById(sessionId);
         -->通过sessionId在存储里查找session
    2. 如果根据sessionId没有找到sesssion并且create参数为true，则新建
      --> S session = SessionRepositoryFilter.this.sessionRepository.createSession();