Struts2 hello world搭建&Struts知识概要整理

• 编辑拦截器继承HandlerInterceptor接口
• 使用注解@Configuration
• 类继承WebMvcConfigurerAdapter类
• 重写类addInterceptors方法，添加需要的拦截器地址

编写Interceptor -- OneInterceptor

public class OneInterceptor implements HandlerInterceptor  {

    /**
     * 在请求处理之前进行调用（Controller方法调用之前）
     */
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, 
            Object object) throws Exception {
        
        System.out.println("被one拦截，放行...");
        return true;  //返回true表示放行， 需要被拦截添加下面的判断，返回false
        
/*      if (true) {
            returnErrorResponse(response, IYounghareJSONResult.errorMsg("被one拦截..."));
        }
        
        return false;*/
    }
    
    /**
     * 请求处理之后进行调用，但是在视图被渲染之前（Controller方法调用之后）
     */
    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, 
            Object object, ModelAndView mv)
            throws Exception {
        // TODO Auto-generated method stub
        
    }
    
    /**
     * 在整个请求结束之后被调用，也就是在DispatcherServlet 渲染了对应的视图之后执行
     * （主要是用于进行资源清理工作）
     */
    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, 
            Object object, Exception ex)
            throws Exception {
        // TODO Auto-generated method stub
        
    }
    
    public void returnErrorResponse(HttpServletResponse response, IYounghareJSONResult result)
            throws IOException, UnsupportedEncodingException {
        OutputStream out=null;
        try{
            response.setCharacterEncoding("utf-8");
            response.setContentType("text/json");
            out = response.getOutputStream();
            out.write(JsonUtils.objectToJson(result).getBytes("utf-8"));
            out.flush();
        } finally{
            if(out!=null){
                out.close();
            }
        }
    }
}

编写Interceptor -- TwoInterceptor

public class TwoInterceptor implements HandlerInterceptor  {

    final static Logger log = LoggerFactory.getLogger(TwoInterceptor.class);
    
    /**
     * 在请求处理之前进行调用（Controller方法调用之前）
     */
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object object) throws Exception {
        
        if (true) {
            returnErrorResponse(response, IYounghareJSONResult.errorMsg("被two拦截..."));
        }
        
        System.out.println("被two拦截...");
        
        return false;
    }
    
    /**
     * 请求处理之后进行调用，但是在视图被渲染之前（Controller方法调用之后）
     */
    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object object, ModelAndView mv)
            throws Exception {
        // TODO Auto-generated method stub
        
    }
    
    /**
     * 在整个请求结束之后被调用，也就是在DispatcherServlet 渲染了对应的视图之后执行（主要是用于进行资源清理工作）
     */
    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object object, Exception ex)
            throws Exception {
        // TODO Auto-generated method stub
        
    }
    
    public void returnErrorResponse(HttpServletResponse response, IYounghareJSONResult result) throws IOException, UnsupportedEncodingException {
        OutputStream out=null;
        try{
            response.setCharacterEncoding("utf-8");
            response.setContentType("text/json");
            out = response.getOutputStream();
            out.write(JsonUtils.objectToJson(result).getBytes("utf-8"));
            out.flush();
        } finally{
            if(out!=null){
                out.close();
            }
        }
    }
}

类使用@Configuration配置拦截器，类继承WebMvcConfigurerAdapter类

@Configuration
public class WebMvcConfigurer extends WebMvcConfigurerAdapter {

    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        /**
         * 拦截器按照顺序执行
         */
        registry.addInterceptor(new TwoInterceptor()).addPathPatterns("/two/**")//拦截路径
                                                     .addPathPatterns("/one/**");
        registry.addInterceptor(new OneInterceptor()).addPathPatterns("/one/**");
        
        super.addInterceptors(registry);
    }

}

运行项目

http://localhost:8080/one/index

拦截结果

后续需要学习的有
nosql:mongodb,memcache
分布式中间件：zookeeper、dubbo
springcloud