springMVC拦截器HandlerInterceptor用法代码示例

摘要:很多时候我们都会去修改其他同事的bug，甚至是已经离职的同事的bug，有时候我们点击页面去不着到后台对应的是哪个controller，针对这个问题，其实我们可以通过sprngmvc的拦截器来拦击用户的请求从而知道页面请求的是哪个class的哪个方法，当然这些打印日志信息肯能并不适合放在生产环境，或者这个拦截器也是非必要的。。。。

一、HandlerInterceptor用法

第一步：注册拦截器

<!-- 注册拦截器 -->
	<mvc:interceptors>
		<bean class="com.project.base.interceptor.ControlInterceptor" />
	</mvc:interceptors>

第二步：继承HandlerInterceptor ，实现拦截器

package com.iflashbuy.limanman;
import java.util.Iterator;
import java.util.Map;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;
public class ControlInterceptor implements HandlerInterceptor{
	private Logger logger = LoggerFactory.getLogger(getClass());
	/**
	 * 执行完控制器后调用，即离开时
	 */
	@Override
		public void afterCompletion(HttpServletRequest request,
				HttpServletResponse response, Object arg2, Exception arg3)
						throws Exception {
	}
	@Override
		public void postHandle(HttpServletRequest arg0, HttpServletResponse arg1, Object arg2, ModelAndView arg3)
				throws Exception {
		// TODO Auto-generated method stub
	}
	@Override
		public Boolean preHandle(HttpServletRequest request, HttpServletResponse arg1, Object arg2) throws Exception {
		int i = 1;
		try {
			@SuppressWarnings("unchecked")
						Map<String, Object> parmMap = request.getParameterMap();
			Iterator<String> iter = parmMap.keySet().iterator();
			while (iter.hasNext()) {
				Object key = iter.next();
				Object value = parmMap.get(key);
				logger.info("第" + i + "个param---->{}-{}", key, value);
				i = i + 1;
			}
		}
		catch (Exception e) {
			i = 1;
		}
		i = 1;
		return true;
	}
}

二、后台打印信息效果

三、拓展使用拦截器实现http基本认证

/**
	 * 执行完控制器后调用，即离开时
	 */
@Override
	public void afterCompletion(HttpServletRequest request,
			HttpServletResponse response, Object arg2, Exception arg3)
			throws Exception {
	logger.info("className--->" + arg2);
	logger.info("request--->" + request);
}
@Override
	public void postHandle(HttpServletRequest request,
			HttpServletResponse response, Object arg2, ModelAndView arg3)
			throws Exception {
}
@Override
	public Boolean preHandle(HttpServletRequest request,
			HttpServletResponse response, Object arg2) throws Exception {
	String sessionAuth = (String) request.getSession().getAttribute("auth");
	if (sessionAuth != null) {
		System.out.println("this is next step");
		nextStep(request, response);
	} else {
		if (!checkHeaderAuth(request, response)) {
			response.setStatus(401);
			response.setHeader("Cache-Control", "no-store");
			response.setDateHeader("Expires", 0);
			response.setHeader("WWW-authenticate", "Basic Realm=\"请输入管理员账号密码\"");
			return false;
		}
	}
	return true;
}
private Boolean checkHeaderAuth(HttpServletRequest request,
			HttpServletResponse response) throws IOException {
	String auth = request.getHeader("Authorization");
	System.out.println("auth encoded in base64 is " + getFromBASE64(auth));
	if ((auth != null) && (auth.length() > 6)) {
		auth = auth.substring(6, auth.length());
		String decodedAuth = getFromBASE64(auth);
		System.out.println("auth decoded from base64 is " + decodedAuth);
		request.getSession().setAttribute("auth", decodedAuth);
		return true;
	} else {
		return false;
	}
}
private String getFromBASE64(String s) {
	if (s == null)
				return null;
	try {
		byte[] encodeBase64 = Base64.encodeBase64(s.getBytes("UTF-8"));
		return new String(encodeBase64);
	}
	catch (UnsupportedEncodingException e) {
		return null;
	}
}
public void nextStep(HttpServletRequest request,
			HttpServletResponse response) throws IOException {
	System.out.println("you can go to the controller");
}

总结

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