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