???JSP?????????

????????

???JSP??????????????JSP?????Java??????????????????????????????????????????????????

?????????

1. ????????

???????Tag??????????????????????????

package me.gacl.web.tag;
import java.io.IOException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.jsp.JspException;
import javax.servlet.jsp.JspWriter;
import javax.servlet.jsp.PageContext;
import javax.servlet.jsp.tagext.Tag;
public class ViewIPTag implements Tag {
    private PageContext pageContext;
    @Override
    public int doEndTag() throws JspException {
        System.out.println("??doEndTag()??");
        return 0;
    }
    @Override
    public int doStartTag() throws JspException {
        System.out.println("??doStartTag()??");
        HttpServletRequest request = (HttpServletRequest) pageContext.getRequest();
        JspWriter out = pageContext.getOut();
        String ip = request.getRemoteAddr();
        try {
            out.write(ip);
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
        return 0;
    }
    @Override
    public Tag getParent() {
        return null;
    }
    @Override
    public void release() {
        System.out.println("??release()??");
    }
    @Override
    public void setPageContext(PageContext pageContext) {
        System.out.println("setPageContext(PageContext pageContext)");
        this.pageContext = pageContext;
    }
    @Override
    public void setParent(Tag arg0) {
    }
}

2. ???????

??????????WEB-INF/tld???????


   
   
    
    
        
     
      viewIP
     
        
     
      me.gacl.web.tag.ViewIPTag
     
        
     
      empty

?JSP??????????

?????

?JSP????????????

<%@ page language="java" pageEncoding="UTF-8" %>
<%@ taglib uri="/gacl" prefix="xdp" %>

????

????????IP??????????

?????????

????JSP??????????????setPageContext??PageContext???????

????????setParent?????????????????

?????????????????????doStartTag???

?????????????????????doEndTag???

??????????????release????????

???JSP????Java??????

package org.apache.jsp;
import javax.servlet.http.*;
import javax.servlet.jsp.*;
public class jspTag_005fTest1_jsp extends HttpJspBase {
    private static final JspFactory _jspxFactory = JspFactory.getDefaultFactory();
    private static java.util.List _jspx_dependants;
    static {
        _jspx_dependants = new java.util.ArrayList(1);
        _jspx_dependants.add("/WEB-INF/gacl.tld");
    }
    private org.apache.jasper.runtime.TagHandlerPool _005fjspx_005ftagPool_005fxdp_005fviewIP_005fnobody;
    private javax.el.ExpressionFactory _el_expressionfactory;
    private org.apache.AnnotationProcessor _jsp_annotationprocessor;
    public Object getDependants() {
        return _jspx_dependants;
    }
    public void _jspInit() {
        _005fjspx_005ftagPool_005fxdp_005fviewIP_005fnobody = org.apache.jasper.runtime.TagHandlerPool.getTagHandlerPool(getServletConfig());
        _el_expressionfactory = _jspxFactory.getJspApplicationContext(getServletConfig().getServletContext()).getExpressionFactory();
        _jsp_annotationprocessor = (org.apache.AnnotationProcessor) getServletConfig().getServletContext().getAttribute(org.apache.AnnotationProcessor.class.getName());
    }
    public void _jspDestroy() {
        _005fjspx_005ftagPool_005fxdp_005fviewIP_005fnobody.release();
    }
    public void _jspService(HttpServletRequest request, HttpServletResponse response)
            throws IOException, ServletException {
        PageContext pageContext = null;
        HttpSession session = null;
        ServletContext application = null;
        ServletConfig config = null;
        JspWriter out = null;
        Object page = this;
        JspWriter _jspx_out = null;
        PageContext _jspx_page_context = null;
        try {
            response.setContentType("text/html;charset=UTF-8");
            pageContext = _jspxFactory.getPageContext(this, request, response, null, true, 8192, true);
            _jspx_page_context = pageContext;
            application = pageContext.getServletContext();
            config = pageContext.getServletConfig();
            session = pageContext.getSession();
            out = pageContext.getOut();
            _jspx_out = out;
            out.write("
   
");
            out.write("??????IP");
            out.write("
   
");
            String ip = request.getRemoteAddr();
            out.write(ip);
            if (_jspx_meth_xdp_005fviewIP_005f0(_jspx_page_context)) {
                return;
            }
        } catch (Throwable t) {
            if (!(t instanceof SkipPageException)) {
                out = _jspx_out;
                if (out != null && out.getBufferSize() != 0) {
                    try {
                        out.clearBuffer();
                    } catch (IOException e) {
                    }
                }
                if (_jspx_page_context != null) {
                    _jspx_page_context.handlePageException(t);
                }
            }
        } finally {
            _jspxFactory.releasePageContext(_jspx_page_context);
        }
    }
    private boolean _jspx_meth_xdp_005fviewIP_005f0(PageContext _jspx_page_context)
            throws Throwable {
        PageContext pageContext = _jspx_page_context;
        JspWriter out = pageContext.getOut();
        me.gacl.web.tag.ViewIPTag _jspx_th_xdp_005fviewIP_005f0 = (me.gacl.web.tag.ViewIPTag) _005fjspx_005ftagPool_005fxdp_005fviewIP_005fnobody.get(me.gacl.web.tag.ViewIPTag.class);
        _jspx_th_xdp_005fviewIP_005f0.setPageContext(pageContext);
        _jspx_th_xdp_005fviewIP_005f0.setParent(null);
        int _jspx_eval_xdp_005fviewIP_005f0 = _jspx_th_xdp_005fviewIP_005f0.doStartTag();
        if (_jspx_th_xdp_005fviewIP_005f0.doEndTag() == javax.servlet.jsp.tagext.Tag.SKIP_PAGE) {
            _005fjspx_005ftagPool_005fxdp_005fviewIP_005fnobody.reuse(_jspx_th_xdp_005fviewIP_005f0);
            return true;
        }
        _005fjspx_005ftagPool_005fxdp_005fviewIP_005fnobody.reuse(_jspx_th_xdp_005fviewIP_005f0);
        return false;
    }
}