我写了一个方法和一个servlet
但我不知道怎样在jsp吊用!以下是代码?
方法:
public int checkmember(){
DataManager dm = DataManagerImpl.getDataManager ();
StringBuffer sql = new StringBuffer("select count(*) from member where user='");
sql.append(this.getUser());
sql.append("'");
log.debug(sql.toString());
int count=dm.execQueryStatistics(sql.toString());
return count;
}
servlet:
public class CheckMember extends HttpServlet{
static Logger log = Logger.getLogger(CheckMember.class);
public void doPost(HttpServletRequest request,HttpServletResponse res)
throws IOException ,ServletException
{
res.setContentType ("text/html;charset=GB2312");
PrintWriter out = res.getWriter();
Member m=new Member();
if(request.getParameter("id")!=null)
m.setId(Integer.parseInt(request.getParameter("id")));
if(m.checkmember () > 0){
//判断用户名是否存在
out.println ("<%@ page contentType=\"text/html; charset=GBK\" %>");
out.println("<html>");
out.println("<head>");
out.println("<title>revise</title>");
out.println("</head>");
out.println("<body>");
out.println ("<script language=\"javascript\">");
out.println ("alert(\"此用户名已存在!\")");
out.println ("history.back(1)");
out.println ("</script>");
out.println("</body>");
out.println("</html>");
}
}
jsp中怎么写!谢谢
但我不知道怎样在jsp吊用!以下是代码?
方法:
public int checkmember(){
DataManager dm = DataManagerImpl.getDataManager ();
StringBuffer sql = new StringBuffer("select count(*) from member where user='");
sql.append(this.getUser());
sql.append("'");
log.debug(sql.toString());
int count=dm.execQueryStatistics(sql.toString());
return count;
}
servlet:
public class CheckMember extends HttpServlet{
static Logger log = Logger.getLogger(CheckMember.class);
public void doPost(HttpServletRequest request,HttpServletResponse res)
throws IOException ,ServletException
{
res.setContentType ("text/html;charset=GB2312");
PrintWriter out = res.getWriter();
Member m=new Member();
if(request.getParameter("id")!=null)
m.setId(Integer.parseInt(request.getParameter("id")));
if(m.checkmember () > 0){
//判断用户名是否存在
out.println ("<%@ page contentType=\"text/html; charset=GBK\" %>");
out.println("<html>");
out.println("<head>");
out.println("<title>revise</title>");
out.println("</head>");
out.println("<body>");
out.println ("<script language=\"javascript\">");
out.println ("alert(\"此用户名已存在!\")");
out.println ("history.back(1)");
out.println ("</script>");
out.println("</body>");
out.println("</html>");
}
}
jsp中怎么写!谢谢
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<servlet-name>Servlet Name</servlet-name>
<servlet-class>com.xx.xx.CheckMember </servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>Servlet Name</servlet-name>
<url-pattern>/CheckMember</url-pattern>
</servlet-mapping>jsp中使用http://ip:port/context path/CheckMember 请求校验
这样可以不用刷新页面
当然通过servlet或者struts等都能实现
给你个ajax通过servlet实现的小例子吧
功能是在一个JSP页面内输入一个名字 然后点击一个按钮从数据库中判断是否存在
存在返回个alert提示“存在” 反之就是“不存在”JSP:
<script type="text/javascript">
var xmlreq = false;
function newXMLHttpRequest() {
if (window.XMLHttpRequest) {
// 在非Microsoft浏览器中创建XMLHttpRequest对象
xmlreq = new XMLHttpRequest();
} else if (window.ActiveXObject) {
//通过MS ActiveX创建XMLHttpRequest
try {
// 尝试按新版InternetExplorer方法创建
xmlreq = new ActiveXObject("Msxml2.XMLHTTP");
} catch (e1) {
// 创建请求的ActiveX对象失败
try {
// 尝试按老版InternetExplorer方法创建
xmlreq = new ActiveXObject("Microsoft.XMLHTTP");
} catch (e2) {
// 不能通过ActiveX创建XMLHttpRequest
}
}
}
return xmlreq;
}
function startRequest(){
newXMLHttpRequest();
var name=document.getElementById("name");
var url="http://localhost:9090/Str_Hib/servlet/AjaxServlet?name="+name.value;
//servlet处理类路径 也称服务器端处理类路径
xmlreq.open("GET",url,true);
xmlreq.onreadystatechange=callback;
xmlreq.send(null);
//alert(name.value);
}
function callback(){
if(xmlreq.readyState == 4)// 完成
{
if(xmlreq.status == 200)//ok 404not found
{
//var mes= xmlreq.responseXML.getElementsByTagName("message")[0].firstChild.data;
var xmlReturn = xmlreq.responseText;
alert(xmlReturn);
}
}
}
</script>
<FORM action="#">
<INPUT type="text" name="name"/>
<INPUT type="button" value="Start"
onclick="startRequest();"/>//调用的JS方法
</FORM>
servlet主要代码:
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException { response.setContentType("text/html");
PrintWriter out = response.getWriter();
String name=(String)request.getParameter("name");
System.out.println("name="+name);
try {
if(Checkout(name)){
out.println("user exist");
System.out.println("user exist");//存在
}else{
out.println("user no exist");
System.out.println("user no exist");//不存在
}
} catch (Exception e) {
e.printStackTrace();
}
System.out.println("servlet over");
//out.flush();
out.close();
}
public boolean Checkout(String username) throws Exception {
Connection con = null;
PreparedStatement pstm = null;
ResultSet rs = null;
ConnectionFactoryOracle cfo=new ConnectionFactoryOracle();
//数据库连接工厂类
try
{
con = cfo.getConnection();//得到connection
pstm = con.prepareStatement("select * from a_person where name=?");//查询
pstm.setString(1,username);
rs = pstm.executeQuery();
int i=0;
String name=null;
while(rs.next())
{
name = rs.getString("name");
i++;
}
if(username.equals(name)){
return true;
}
}
catch(SQLException e)
{
e.printStackTrace();
}
finally
{
SQLUtil.close(pstm, con);
}
return false;
}
}其他配置文件不说了 我想你应该懂