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

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

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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??????????

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

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

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

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????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;    }}