1.java类,使用简单标签,jsp2.0规范, 继承 SimpleTagSupport

public class ViewIpSimpleTag extends SimpleTagSupport {    @Override    public void doTag() throws JspException, IOException {        PageContext pageContext = (PageContext) this.getJspContext();        String ip = ((HttpServletRequest) pageContext.getRequest()).getRemoteAddr();        pageContext.getOut().write(ip);    }}

 

1.java类,使用传统标签 jsp1.0, 继承 TagSupport(弃用)

/** * jsp 自定义标签的步骤： *     1.写一个类实现Tag接口(继承TagSupport类) *     2.在WEB-INF文件夹中新建一个tld文件 *     3.在jsp  页面中导入taglib标签库，然后调用  * */public class ViewIp extends TagSupport {    @Override    public int doStartTag() throws JspException {        try {            HttpServletRequest request = (HttpServletRequest) this.pageContext                    .getRequest();            JspWriter out = this.pageContext.getOut();            String ip = request.getRemoteAddr();            out.print(ip);        } catch (IOException e) {            e.printStackTrace();        }        return super.doStartTag();    }}

2.tld文件(/webProjectName/WEB-INF/web.tld)

     
         
      
       1.0
          
      
       web
          
      
       www.bvb.de
          
              
       
        viewIp
               
       
        de.bvb.web.tag.ViewIpSimpleTag
               
       
        empty
           
      
     

 

3.jsp页面

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
     <%@ taglib prefix="web" uri="www.bvb.de"%>             你的ip是：        
             
             不使用自定义标签        <%        String ip = request.getRemoteAddr();        out.print(ip);        %>