手写一个轻量级的网关API

以HTTP接口形式的应用,是目前大部分中小型企业最常见的微服务夸语言交互的实现方式

即:定义多个接口,外部调用,经网关解析进行分发，小编遇到的这种情况是，有多个服务，每个服务都需要单独有网关开墙，很是头疼，每上线一个服务都需要网关配置，极其头疼，再次实现一种暴露一个接口，通过参数来实现调用不同的方法的案例，

注意:改方案只适合学习,不适合线上项目

GITHUB项目地址

目录

思路分析

流程图

实现方案:

• 1. 自定义注解 APiMapping
  2. 自定义ApiGateWayServlet
  3. 利用 Spring IOC 拆分方法并与 ApiMaping 做绑定由 ApiStore中HashMap维护

注解定义及利用IOC绑定注解与方法

api注解: APIMapping

      @Retention(RetentionPolicy.RUNTIME)
      @Target(ElementType.METHOD)
      public @interface APIMapping {
          String value();
          RequestMethod method();
      }
  
 

通过注解对业务方法标记

       @APIMapping(value = "biz.api.order",method = RequestMethod.GET)
         public OrderInfo getOrderInfo(String orderId) {
             OrderInfo orderInfo = OrderInfo.builder().id(orderId).name("测试订单").price(12.2).build();
             return orderInfo;
          }
         @APIMapping(value = "biz.api.order2",method = RequestMethod.POST)
         public OrderInfo getOrderDo(OrderInfo orderInfo){
             return orderInfo;
          }
  
 

利用Spring 上下文对标记的方法进行绑定
初始化时候，扫描APIMapping接口

      String[] names = applicationContext.getBeanDefinitionNames();
             Class<?> type;
              for (String name : names) {
                 type = applicationContext.getType(name);
                  for (Method method : type.getDeclaredMethods()) {
       APIMapping apiMapping = method.getDeclaredAnnotation(APIMapping.class);
       if (apiMapping!=null){
       addApiItem(apiMapping,name,method);
       }
                  }
              }
  
 

重写自定义Servlet方法中的POST和GET

      public class ApiGateWayServlet extends HttpServlet {
         private ApplicationContext applicationContext;
         private ApiGateWayHandler apiGateWayHandler;
         @Override
          public void init() throws ServletException {
             super.init();
              applicationContext = WebApplicationContextUtils.getWebApplicationContext(getServletContext());
              apiGateWayHandler = applicationContext.getBean(ApiGateWayHandler.class);
          }
         @Override
         protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
              apiGateWayHandler.handle(req,resp);
          }
         @Override
         protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
              apiGateWayHandler.handle(req,resp);
          }
      }
  
 

  
 
 

根据接口绑定获取到执行的方法,利用反射执行

      public class ApiRunnable {
             private String apiName;
             private Method targetMethod;
             private String targetName;
             private Object target;
             private String Method;
  
 

      Object result = null;
             Object target = apiRunable.getTarget();
              Method targetMethod = apiRunable.getTargetMethod();
             Set<Method> methods = ReflectionUtils.getMethods(target.getClass(), ReflectionUtils.withName(targetMethod.getName()));
             Iterator<Method> iterator = methods.iterator();
              Method method = null;
             while (iterator.hasNext()) {
                  method = iterator.next();
              }
              Class<?>[] parameterTypes = method.getParameterTypes();
             try {
                  Class<?> aClass = Class.forName(parameterTypes[0].getName());
                  Class<String> stringClass = String.class;
                 if (stringClass == aClass) {
                      result = apiRunable.run(parameter);
              ....
  
 

  
 
 

文章来源: springlearn.blog.csdn.net，作者：西魏陶渊明，版权归原作者所有，如需转载，请联系作者。

原文链接：springlearn.blog.csdn.net/article/details/102425339