强化Servlet Request 对象方法

适用场景：
需要同时从request对象的getParameter（），getCookies(),getHeader()中取值：

方法一：装饰模式:

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;

/**
 * description
 * 
 * @author qiaoyao
 * @version 1.0,2010-5-27
 */
public class ApiRequestWrapper extends HttpServletRequestWrapper {

	public ApiRequestWrapper(HttpServletRequest request) {
		super(request);
	}

	public String getParameter(String parameter) {
		String getValue = null;
		getValue = super.getParameter(parameter);
		if (StringUtils.isNullOrEmpty(getValue)) {
			getValue = super.getHeader(parameter);
			if (StringUtils.isNullOrEmpty(getValue)) {
				return null;
			}
		}
		return getValue;
	}
}

spring过滤器调用如下：

protected void doFilterInternal(HttpServletRequest request,
			HttpServletResponse response, FilterChain filterChain)
			throws ServletException, IOException {
		
			super.doFilterInternal(new ApiRequestWrapper ( request), response, filterChain);		
          	}

方法二：代理模式：

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;

import javax.servlet.http.HttpServletRequest;

/**
 * description
 * 
 * @author qiaoyao
 * @version 1.0,2010-5-27
 */
public class RequestHandler implements InvocationHandler {
	private HttpServletRequest realRequest;
	private HttpServletRequest wrappedHttpServletRequest;

	@Override
	public Object invoke(Object proxy, Method method, Object[] args)
			throws Throwable {
		if ("getPrameter".equals(method.getName())) {
			// doSomeThing
			return "result";
		}
		return method.invoke(realRequest, args);
	}

	public HttpServletRequest bind() {
		this.wrappedHttpServletRequest = (HttpServletRequest) Proxy
				.newProxyInstance(this.getClass().getClassLoader(),
						new Class[] { HttpServletRequest.class }, this);
		return this.wrappedHttpServletRequest;
	}

}

spring过滤器调用如下：

protected void doFilterInternal(HttpServletRequest request,
			HttpServletResponse response, FilterChain filterChain)
			throws ServletException, IOException {
		RequestHandler requestHandler = new RequestHandler(request);
	request = requestHandler.bind();
			super.doFilterInternal(request, response, filterChain);		
          	}

如果不需要所有参数都在多个范围取值：   可以通过参数名判断怎样取。