来源: 互联网  发布时间: 2014-02-18

深入理解wifi direct

wifi direct 又称 wifi peer-to-peer，优势为直连，无需通过无线局域网。

 

wifi direct和蓝牙类似，但传输距离、速度都优于蓝牙，但耗电量较大。

 

wifi dierect本机有效传输距离可达十米

 

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SSID，本机作为wifi热点的时候显示给其他设备的网络名称。

 

MAC地址，网卡的物理地址，具有全球唯一性，当然也可以修改。当给机器安装操作系统时，会将MAC地址读到注册表中，之后每次需要这个值的时候都默认从注册表中读取，所以可以通过修改注册表的MAC值来修改本机MAC地址。

    

    来源: 互联网  发布时间: 2014-02-18

spring security3用户登录相关

package com.security;

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.security.core.AuthenticationException;
import org.springframework.security.web.authentication.AuthenticationFailureHandler;

public class OnLoginFaild implements AuthenticationFailureHandler {

	@Override
	public void onAuthenticationFailure(HttpServletRequest request,
			HttpServletResponse response, AuthenticationException exception)
			throws IOException, ServletException {
		String errorMSG=exception.getMessage();//User is disabled
		//Bad credentials
		System.out.println("errorMSG:"+exception.getMessage());
		if(!("".equals(errorMSG)))response.sendRedirect(request.getContextPath()+"/others_handler/login_faild/"+errorMSG);
	}
}

spring-security.xml配置中的修改

<http pattern="/login.jsp" security="none"/>
    <http access-denied-page="/others_handler/no_power_access"><!-- 当访问被拒绝时，会转到403.jsp -->
		<form-login login-page="/login.jsp"
			authentication-failure-handler-ref="onLoginFaild"
			authentication-failure-url="/others_handler/login_faild/*"
			default-target-url="/others_handler/login_success" /><!-- 登录成功跳转到index.jsp -->
		<logout logout-success-url="/login.jsp" />
		<custom-filter before="FILTER_SECURITY_INTERCEPTOR" ref="myFilter" />
	</http>

以上配置中authentication-failure-handler-ref="onLoginFaild"
表示登录失败时候跳转到anLoginFaild这个bean中

<http pattern="/login.jsp" security="none"/>这个配置当请求/login.jsp时，security不会去拦截，也就不过org.springframework.security.access.intercept.AbstractSecurityInterceptor
拦截器，所以在/login.jsp页面用org.springframework.security.core.context.SecurityContextHolder.getContext().getAuthentication()
也就获得不了用户信息

    

    来源: 互联网  发布时间: 2014-02-18

java获取socket发送过来的数据并返回数据

<r><i>

<a><![CDATA["  + username +  "]]></a>"   

+ "<b><![CDATA["  + password +  "]]></b>"   

+ "<d><![CDATA["  + presentUsername +  "]]></d>"   

+ "<c>"  + makeListToXML(presentGoodsList) +  "</c>"   

</i></r>"

import org.dom4j.Document;
import org.dom4j.Element;
import org.dom4j.io.SAXReader;


InputStream tempIS = null;
        try{
            tempIS = request.getInputStream();
        }catch(IOException ex){
            logger.info(ex);
        }
       SAXReader reader = new SAXReader(false);
       Document doc = reader.read(tempIS);
       tempIS.close();
       Element rootElement = doc.getRootElement();//r节点
       Element children = rootElement.element("i");//r节点的子节点i
       userName = children.element("a").getText();//i节点的子节点a
       password = children.element("b").getText();//i节点的子节点b
       presentUsername = children.element("d").getText();//i节点的子节点d
       Element goodsChildren = children.element("c");//i节点的子节点c






String xml = "";
		String xmlHead = "<r>";
		String xmlFoot = "</r>";
		StringBuffer xmlCenter = new StringBuffer();
		
		//用户金钱信息
		xmlCenter.append("<a>" + resFlg + "</a>\n");
		if(resFlg == Constant.BUY_SUCCESS){
			xmlCenter.append("<b>" + "x" + "</b>\n");
			xmlCenter.append("<c>" + "y"+ "</c>\n");
			xmlCenter.append("<d>" + "z" + "</d>\n");
		}
		
		xml = xmlHead + xmlCenter.toString() + xmlFoot;
		request.setAttribute("xmlResult", xml);
		return actionMapping.findForward("returnData");






<%@ page contentType="text/html; charset=utf-8" %>
<%@ taglib uri="/WEB-INF/struts-logic.tld" prefix="logic" %>
<%@ taglib uri="/WEB-INF/struts-bean.tld" prefix="bean" %>
<logic:present name="xmlResult">
<bean:write filter="false" name="xmlResult" />
</logic:present>