js 异步请求

<p id="check">
	<label>验证码：</label>
	<input  class="vid" id="ValidateCode" name="ValidateCode"  type="text" value="" onblur="checkValidateCode()"/>
	<img id="checkcodeimg" src="<%=path %>/image.jsp" style="margin-left:10px;" width="74px" height="28px"  onclick="this.src='<%=path %>/image.jsp?date='+new Date();"/>
	<span id="codeSpan"></span>
</p>

image.jsp

<%@ page contentType="image/jpeg" import="java.awt.*, java.awt.image.*,java.util.*,javax.imageio.*"%>
<%!Color getRandColor(int fc, int bc) {
        Random random = new Random();
        if (fc > 255)
            fc = 255;
        if (bc > 255)
            bc = 255;
        int r = fc + random.nextInt(bc - fc);
        int g = fc + random.nextInt(bc - fc);
        int b = fc + random.nextInt(bc - fc);
        return new Color(r, g, b);
    }%>
<%
    out.clear();//????resin???????tomacat??????
    out = pageContext.pushBody();
    response.setHeader("Pragma", "No-cache");
    response.setHeader("Cache-Control", "no-cache");
    response.setDateHeader("Expires", 0);

    int width = 60, height = 20;
    BufferedImage image = new BufferedImage(width, height,
            BufferedImage.TYPE_INT_RGB);

    Graphics g = image.getGraphics();
    Random random = new Random();

    g.setColor(getRandColor(200, 250));
    g.fillRect(0, 0, width, height);

    g.setFont(new Font("Times New Roman", Font.PLAIN, 18));

    g.setColor(getRandColor(160, 200));
    for (int i = 0; i < 155; i++) {
        int x = random.nextInt(width);
        int y = random.nextInt(height);
        int xl = random.nextInt(12);
        int yl = random.nextInt(12);
        g.drawLine(x, y, x + xl, y + yl);
    }

    String sRand = "";
    for (int i = 0; i < 4; i++) {
        String rand = String.valueOf(random.nextInt(10));
        sRand += rand;

        g.setColor(new Color(20 + random.nextInt(110), 20 + random.nextInt(110), 20 + random.nextInt(110)));
        g.drawString(rand, 13 * i + 6, 16);
    }
    // ??????SESSION
    session.setAttribute("rand", sRand);
    g.dispose();

    ImageIO.write(image, "JPEG", response.getOutputStream());
%>

　　

实现jsp

 var xmlHttpRequest;   
    //XmlHttpRequest对象   
    function createXmlHttpRequest(){   
        if(window.ActiveXObject){ //如果是IE
            return new ActiveXObject("Microsoft.XMLHTTP");   
        }else if(window.XMLHttpRequest){ //非IE浏览器   
            return new XMLHttpRequest();   
        }   
    }   
     function checkValidateCode(){
        code = document.getElementById("ValidateCode").value.trim();
        var url = "user_validateCodeCheck.do?validateCode="+code;
        xmlHttpRequest = createXmlHttpRequest(); 
        xmlHttpRequest.onreadystatechange = HuiDiaoFun; 
        xmlHttpRequest.open("post",url,true); 
        xmlHttpRequest.send(null);  
    }
            
    //回调函数   
    function HuiDiaoFun(){   
        if(xmlHttpRequest.readyState == 4 && xmlHttpRequest.status == 200){
            var resp = xmlHttpRequest.responseText;
            if (resp == "error") {
                document.getElementById("codeSpan").innerHTML = "验证码错误！";
                document.getElementById("codeSpan").style.color = "#FF0000";
            }else if(resp == "ok"){
                document.getElementById("codeSpan").innerHTML = "";
            }
        }   
    }  

public class UserAction extends BaseAction{
    

    private String validateCode;

    
    public void validateCodeCheck(){
        String code = (String)getHttpSession().getAttribute("rand");
        System.out.println(code);
        if(StringUtils.isNoneEmpty(validateCode) && validateCode.equals(code)){
            ResponseUtil.writeUTF(getHttpResponse(), "ok");
        }else{
            ResponseUtil.writeUTF(getHttpResponse(), "error");
        }
    }
    
}




import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import javax.servlet.ServletContext;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import javax.servlet.jsp.PageContext;

import org.apache.struts2.ServletActionContext;
import org.springframework.web.context.support.WebApplicationContextUtils;

import com.opensymphony.xwork2.ActionSupport;



/**
 * action基类，提供共用方法
 * 
 *
 */
public class BaseAction extends ActionSupport {

    public UnitService baseUnitService;
    public RoleService baseRoleService;
    public ConfigService baseConfigService;
    public ChannelService baseChannelService;
    public InfoService baseInfoService;
    public int pageSize=10;
    public int currPage=1;
    public int totalCount=0;
    public String pageStr;
    public String pageFuncId;
    public String showMessage;
    public String forwardUrl="";
    public int forwardSeconds=0;
    public String getForwardUrl() {
        return forwardUrl;
    }
    public void setForwardUrl(String forwardUrl) {
        this.forwardUrl = forwardUrl;
    }
    public int getForwardSeconds() {
        return forwardSeconds;
    }
    public void setForwardSeconds(int forwardSeconds) {
        this.forwardSeconds = forwardSeconds;
    }
    public int getPageSize() {
        return pageSize;
    }
    public void setPageSize(int pageSize) {
        this.pageSize = pageSize;
    }
    public int getCurrPage() {
        return currPage;
    }
    public void setCurrPage(int currPage) {
        this.currPage = currPage;
    }
    public HttpSession getHttpSession(){
        return ServletActionContext.getRequest().getSession();
    }
    public HttpServletRequest getHttpRequest(){
        return ServletActionContext.getRequest();
    }
    public HttpServletResponse getHttpResponse(){
        return ServletActionContext.getResponse();
    }
    public PageContext getPageContext(){
        return ServletActionContext.getPageContext();
    }
    public ServletContext getServletContext(){
        return ServletActionContext.getServletContext();
    }
    public Map<String, Object> getApplication(){
        return ServletActionContext.getContext().getApplication();
    }
    public String getBasePath(){
        String path = getHttpRequest().getContextPath();
        String basePath = getHttpRequest().getScheme()+"://"+getHttpRequest().getServerName()+":"+getHttpRequest().getServerPort()+path+"/";
        return basePath;
    }
    
    
    /**
     * 获取配置
     * @return
     */
    public Map<String, Object> getConfig(){
        if (getApplication().get("config")!=null) {
            return (Map<String, Object>)getApplication().get("config");
        }else {
            //重新生成
            return setConfig();
        }
    }
    /**
     * 获取配置值 
     * @return
     */
    public String getConfigVal(String name){
        Map<String, Object> config=getConfig();
        if (config!=null && config.get(name)!=null) {
            return config.get(name).toString();
        }
        return "";
    }
    /**
     * 设置配置
     * @return
     */
    public Map<String, Object> setConfig(){
         baseConfigService = (ConfigService) getBean("configService");
        List<Config> configList=baseConfigService.find();
        Map<String, Object> config=new HashMap<String, Object>();
        if (configList!=null && configList.size()>0) {
            for (int i = 0; i < configList.size(); i++) {
                config.put(configList.get(i).getCode(), configList.get(i).getConfigvalue());
            }
        }
        getApplication().put("config", config);
        return config;
    }
    public void write(String content,String charset){
        getHttpResponse().setCharacterEncoding(charset);
        getHttpResponse().setContentType("text/html;charset="+charset);
        try {
            getHttpResponse().getWriter().print(content);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    /**
     * 判断是否为admin登录
     */
    public boolean isAdminLogin(){
        return "admin".equals(getLoginName());
    }
    /**
     * 判断是否为站点总管理员
     */
    public boolean isSiteAdmin(){
        if (getHttpSession().getAttribute("siteAdmin")!=null) {
            return (Boolean)getHttpSession().getAttribute("siteAdmin");
        }
        return false;
    }
    /**
     * 获取当前管理站点 
     * @return
     */
    public Site getManageSite(){
        if (getHttpSession().getAttribute("manageSite")!=null) {
            //获取当前管理站点
            return (Site)getHttpSession().getAttribute("manageSite");
        }
        return null;
    }
    /**
     * 获取session中的当前登录用户名
     * @return
     */
    public String getLoginName(){
        if (getLoginAdmin()!=null) {
            return getLoginAdmin().getLoginname();
        }
        return "";
    }
    /**
     * 获取session中的当前登录用户
     * @return
     */
    public Users getLoginAdmin(){
        if (getHttpSession().getAttribute("loginAdmin")!=null) {
            return (Users)getHttpSession().getAttribute("loginAdmin");
        }
        return null;
    }
    /**
     * 获取session中的当前登录会员
     * @return
     */
    public Member getLoginMember(){
        if (getHttpSession().getAttribute("loginMember")!=null) {
            return (Member)getHttpSession().getAttribute("loginMember");
        }
        return null;
    }
    /**
     * 获取session中的当前登录会员组
     * @return
     */
    public Membergroup getLoginMembergroup(){
        if (getHttpSession().getAttribute("loginMembergroup")!=null) {
            return (Membergroup)getHttpSession().getAttribute("loginMembergroup");
        }
        return null;
    }
    /**
     * 获取session中的当前会员登录用户名
     * @return
     */
    public String getLoginMemberName(){
        if (getLoginMember()!=null) {
            return getLoginMember().getLoginname();
        }
        return "";
    }
    
    /**
     * 获取登录用户所属单位
     * @return
     */
    public List<Unit> getLoginUnits(){
        //先判断session是否存在
        HttpSession session=getHttpSession();
        if (session.getAttribute("loginUnits")!=null) {
            return (List<Unit>)session.getAttribute("loginUnits");
        }else {
            //不存在则重新提取
            baseUnitService = (UnitService) getBean("unitService");
            List<Unit> list = baseUnitService.findByUser(getLoginAdmin().getId());
            session.setAttribute("loginUnits", list);
            return list;
        }
    }
    /**
     * 获取登录用户所属单位组成的sql语句
     * 例:'','',''
     * @return
     */
    public String getLoginUnitIdsSql(){
        List<Unit> list=getLoginUnits();
        StringBuilder sb=new StringBuilder();
        if (list!=null && list.size()>0) {
            for (int i = 0; i < list.size(); i++) {
                if (i>0) {
                    sb.append(",");
                }
                sb.append("'"+list.get(i).getId()+"'");
            }
        }
        return sb.toString();
    }
    /**
     * 获取登录用户所属角色
     * @return
     */
    public List<Roles> getLoginRoles(){
        //先判断session是否存在
        HttpSession session=getHttpSession();
        if (session.getAttribute("loginRoles")!=null) {
            return (List<Roles>)session.getAttribute("loginRoles");
        }else {
            //不存在则重新提取
            baseRoleService = (RoleService) getBean("roleService");
            List<Roles> list = baseRoleService.findByUser(getLoginAdmin().getId());
            session.setAttribute("loginRoles", list);
            return list;
        }
    }
    /**
     * 获取登录用户所属角色组成的sql语句
     * 例:'','',''
     * @return
     */
    public String getLoginRoleIdsSql(){
        List<Roles> list=getLoginRoles();
        StringBuilder sb=new StringBuilder();
        if (list!=null && list.size()>0) {
            for (int i = 0; i < list.size(); i++) {
                if (i>0) {
                    sb.append(",");
                }
                sb.append("'"+list.get(i).getId()+"'");
            }
        }
        return sb.toString();
    }
    /**
     * 返回到通用信息提示页面
     * @param msg
     * @param url
     * @param seconds
     * @return
     */
    public String showMessage(String showMessage,String forwardUrl,int forwardSeconds){
        this.showMessage=showMessage;
        this.forwardUrl=forwardUrl;
        this.forwardSeconds=forwardSeconds;
        return "showMessage";
    }
    /**
     * 设置静态化参数
     * @param data
     * @throws UnsupportedEncodingException 
     */
    public void setData(Map<String,Object> data,Site site) throws UnsupportedEncodingException{
        //传递site参数
        data.put("site", site);
        data.put("contextPath", getContextPath());
        data.put("contextPathNo", getContextPathNo());
        data.put("request_remoteAddr", getHttpRequest().getRemoteAddr());
        //获取参数并放入data
        Enumeration<String> paramNames=getHttpRequest().getParameterNames();
        if (paramNames!=null && paramNames.hasMoreElements()) {
            String name;
            while (paramNames.hasMoreElements()) {
                name=paramNames.nextElement();
                if (name!=null &&
                        !name.equals("site") &&
                        !name.equals("contextPath")&&
                        !name.equals("currChannelid")&&
                        !name.equals("currInfoid")) {
                    if(name.equals("key")){
                        String key = new String(getHttpRequest().getParameter(name).getBytes(),"UTF-8");
                        data.put(name, key);
                    }else{
                        data.put(name, getHttpRequest().getParameter(name));
                    }
                }
            }
        }
        //如果有currChannelid参数则传递currChannel对象
        if (getHttpRequest().getParameter("currChannelid")!=null && getHttpRequest().getParameter("currChannelid").trim().length()>0) {
            baseChannelService = (ChannelService) getBean("channelService");
            data.put("currChannel",baseChannelService.findById(getHttpRequest().getParameter("currChannelid")));
        }
        //如果有currInfoid参数则传递currInfo对象
        if (getHttpRequest().getParameter("currInfoid")!=null && getHttpRequest().getParameter("currInfoid").trim().length()>0) {
            baseInfoService = (InfoService) getBean("infoService");
            data.put("currInfo",baseInfoService.findById(getHttpRequest().getParameter("currInfoid")));
        }
        //获取seesion中存放的变量
        Enumeration<String> sessionNames=getHttpSession().getAttributeNames();
        if (sessionNames!=null && sessionNames.hasMoreElements()) {
            String name;
            while (sessionNames.hasMoreElements()) {
                name=sessionNames.nextElement();
                if (name!=null) {
                    //session变量名称改为session_变量名，避免重名
                    data.put("session_"+name, getHttpSession().getAttribute(name));
                }
            }
        }
    }
    public String getContextPath(){
        return getHttpRequest().getContextPath()+"/";
    }
    public String getContextPathNo(){
        return getHttpRequest().getContextPath()+"/";
    }
    public String getPageStr() {
        return pageStr;
    }
    public void setPageStr(String pageStr) {
        this.pageStr = pageStr;
    }
    public int getTotalCount() {
        return totalCount;
    }
    public void setTotalCount(int totalCount) {
        this.totalCount = totalCount;
    }
    public String getPageFuncId() {
        return pageFuncId;
    }
    public void setPageFuncId(String pageFuncId) {
        this.pageFuncId = pageFuncId;
    }
    public UnitService getBaseUnitService() {
        return baseUnitService;
    }
    public void setBaseUnitService(UnitService baseUnitService) {
        this.baseUnitService = baseUnitService;
    }
    public RoleService getBaseRoleService() {
        return baseRoleService;
    }
    public void setBaseRoleService(RoleService baseRoleService) {
        this.baseRoleService = baseRoleService;
    }
    public ConfigService getBaseConfigService() {
        return baseConfigService;
    }
    public void setBaseConfigService(ConfigService baseConfigService) {
        this.baseConfigService = baseConfigService;
    }
    public String getShowMessage() {
        return showMessage;
    }
    public void setShowMessage(String showMessage) {
        this.showMessage = showMessage;
    }

    public ChannelService getBaseChannelService() {
        return baseChannelService;
    }
    public void setBaseChannelService(ChannelService baseChannelService) {
        this.baseChannelService = baseChannelService;
    }
    public InfoService getBaseInfoService() {
        return baseInfoService;
    }
    public void setBaseInfoService(InfoService baseInfoService) {
        this.baseInfoService = baseInfoService;
    }
    
    public Object getBean(String bean) {
        return WebApplicationContextUtils.getWebApplicationContext(
                ServletActionContext.getRequest().getSession().getServletContext()).getBean(bean);
    }
}