AbstractHandlerMethodAdapter类简介说明

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AbstractHandlerMethodAdapter类简介说明

下文笔者将讲述AbstractHandlerMethodAdapter类的简介说明，如下所示:

AbstractHandlerMethodAdapter是HandlerAdapter接口的简单抽象类
   实现了接口定义的方法(同时预留了子类的实现接口)
   同时增加了执行顺序Order

AbstractHandlerMethodAdapter的源码分析

public abstract class AbstractHandlerMethodAdapter extends WebContentGenerator implements HandlerAdapter, Ordered {  
    private int order = Ordered.LOWEST_PRECEDENCE;  
    public AbstractHandlerMethodAdapter() {  
        //默认情况下不限制HTTP方法
        super(false);  
    }  
    @Override  
    public final boolean supports(Object handler) {  
        return (handler instanceof HandlerMethod && supportsInternal((HandlerMethod) handler));  
    }  
    protected abstract boolean supportsInternal(HandlerMethod handlerMethod);  
    //重写HandlerAdapter的handle方法
    @Override  
    public final ModelAndView handle(HttpServletRequest request, HttpServletResponse response, Object handler)  
            throws Exception {  
  
        return handleInternal(request, response, (HandlerMethod) handler);  
    }  
    //handleInternal主要做如下操作:(1)备好处理器所需要的参数(2)使用处理器处理请求(3)处理返回值，也就是将不同类型的返回值统一处理成ModelAndView类型  
    protected abstract ModelAndView handleInternal(HttpServletRequest request,  
            HttpServletResponse response, HandlerMethod handlerMethod) throws Exception;  
  
    @Override  
    public final long getLastModified(HttpServletRequest request, Object handler) {  
        return getLastModifiedInternal(request, (HandlerMethod) handler);  
    }  
    //提供order功能
    public void setOrder(int order) {  
        this.order = order;  
    }  
    @Override  
    public int getOrder() {  
        return this.order;  
    }  
    protected abstract long getLastModifiedInternal(HttpServletRequest request, HandlerMethod handlerMethod);  
  
}