ajax的简单应用和filter的编写方法

function dss(userId,obj){
$.post("test?flag=2",{id:userId},function(data)
if("删除成功"==data){
alert("删除成功");
$(obj).parent().parent().remove();
}
});
}

<filter>
<filter-name>FirstFilter</filter-name>
<filter-class>com.jkx.web.filter.FirstFilter</filter-class>
<init-param>
<param-name>encoding</param-name>
<param-value>UTF-8</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>FirstFilter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>

package com.jkx.web.filter;
import java.io.IOException;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class FirstFilter implements Filter{
public String encoding=null;
//服务器正常关闭时执行
public void destroy() {
System.out.println("FirstFilter销毁");
}
public void doFilter(ServletRequest request, ServletResponse response,
FilterChain chain) throws IOException, ServletException {
HttpServletRequest req = (HttpServletRequest) request;
HttpServletResponse resp = (HttpServletResponse) response;
req.setCharacterEncoding(encoding);
req.setAttribute("fileParam", "222222");
chain.doFilter(req, resp);
}
//服务器启动时初始化
public void init(FilterConfig filterConfig) throws ServletException {
System.out.println("FirstFilter初始化，被创建");
encoding = filterConfig.getInitParameter("encoding"); 
}
}