JSP自定義標簽獲取用戶IP地址的方法

2024-09-05 00:20:51

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JSP自定義標簽獲取用戶IP地址的方法，需要的朋友可以參考一下

1、編寫一個實現tag接口的標簽處理器類

復制代碼代碼如下:

package cn.itcast.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;

public int doStartTag() throws JspException {

HttpServletRequest request = (HttpServletRequest) pageContext.getRequest();//獲取頁面Servlet中 request 和out 對象
JspWriter out = pageContext.getOut();

String ip = request.getRemoteAddr(); //獲取用戶IP地址
try {
out.write(ip);
} catch (IOException e) {
throw new RuntimeException(e);
}

return 0;
}

public int doEndTag() throws JspException {
return 0;
}
public Tag getParent() {
return null;
}
public void release() {
}
public void setPageContext(PageContext arg0) {
this.pageContext = arg0;//PageContext獲取用戶request out 等對象
}
public void setParent(Tag arg0) {
}
}

2、在web-inf/目錄下新建tld文件，在tld文件中對標簽處理器進行描述

復制代碼代碼如下:

<?xml version="1.0" encoding="UTF-8" ?>

<taglib xmlns="http://java.sun.com/xml/ns/j2ee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee "
version="2.0">

<description>A tag library exercising SimpleTag handlers.</description>
<tlib-version>1.0</tlib-version>
<short-name>SimpleTagLibrary</short-name>
<uri>/itcast</uri>

<tag>
<name>viewIP</name> 
<tag-class>cn.itcast.web.tag.ViewIPTag</tag-class>
<body-content>empty</body-content>
</tag>
</taglib>

3、在jsp頁面中導入并使用自定義標簽

復制代碼代碼如下:

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%@taglib uri="/itcast" prefix="itcast" %>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>輸出客戶機的IP</title>
</head>

<body>
您的IP是：<itcast:viewIP/>
</body>
</html>