jsp tld 的tag 自定义标签扩展

引入方式

<%@ taglib prefix="bgt" uri="/WEB-INF/tlds/bgt.tld" %>

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写法示例如下：

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

<!DOCTYPE taglib PUBLIC "-//Sun Microsystems, Inc.//DTD JSP Tag Library 1.2//EN"

"http://java.sun.com/dtd/web-jsptaglibrary_1_2.dtd">

<taglib>

<tlib-version>1.0</tlib-version>

<jsp-version>2.0</jsp-version>

<short-name>bgt</short-name>

<!-- backGroundTag -->

<uri>http://www.sdyy.tag</uri>

<tag>

<name>hasUrlPerm</name>

<tag-class>com.sdyy.common.tags.HasUrlPermissionTag</tag-class>

<attribute>

<name>link</name>

<required>false</required>

<rtexprvalue>true</rtexprvalue><!-- 是否支持恶劣表达式 -->

<type>java.lang.String</type>

<description>示例：acApplication/forMain.do</description>

</attribute>

</tag>

</taglib>

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A、【判断标签】HasUrlPermissionTag标签是一个判断标签，通过该标签来决定标签包裹的内容是否显示，写法如下：

package com.sdyy.common.tags;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.jsp.JspException;

import javax.servlet.jsp.tagext.BodyTagSupport;

import com.sdyy.common.spring.interceptor.PermissionInterceptor;

/**

*

*@ClassName: HasUrlPermissionTag

*@Description: 根据url判断权限标签

*@author: liuyx

*@date: 2015年12月21日上午11:15:32

*/

public class HasUrlPermissionTag extends BodyTagSupport {

private String link;//  acApplication/forMain.do

@Override

public int doStartTag() throws JspException { // 在标签开始处出发该方法

HttpServletRequest request=(HttpServletRequest) pageContext.getRequest();

//获取session中存放的权限

//判断是否有权限访问

if (PermissionInterceptor.isOperCanAccess(request, link)) {

    //允许访问标签body

    return BodyTagSupport.EVAL_BODY_INCLUDE;// 返回此则执行标签body中内容，SKIP_BODY则不执行

} else {

    return BodyTagSupport.SKIP_BODY;

}

}

@Override

public int doEndTag() throws JspException {

return BodyTagSupport.EVAL_BODY_INCLUDE;

}

public String getLink() {

return link;

}

public void setLink(String link) {

this.link = link;

}

}

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在JSP中的使用方式：

<bgt:hasUrlPerm link="abc.do"><div>tttttttttttttttttest</div></bgt:hasUrlPerm>

B、【控件标签】，这种标签直接返回一个控件，不过是通过java代码生成的控件内容，写法示例：

package com.sdyy.common.tags;

import java.io.IOException;

import java.util.ArrayList;

import java.util.List;

import javax.servlet.jsp.JspTagException;

import javax.servlet.jsp.JspWriter;

import javax.servlet.jsp.tagext.BodyTagSupport;

/*import com.sdyy.base.ac.ac_permission.model.AcPermission;*/

public class ButtonUrlTag extends BodyTagSupport {

private static final long serialVersionUID = -7811902545513255473L;

//标签属性用户名

private String user = null;

//标签属性操作url

private String url = null;

//标签属性 js方法

private String jsmethod = null;

//标签属性image 按钮图片

private String image = null;

//标签属性 alt 提示

private String alt = null;

//标签属性操作value 按钮文本

private String value  = null;

    /* 标签初始方法*/

public int doStartTag() throws JspTagException{

return super.EVAL_BODY_INCLUDE;

}

    /* 标签结束方法*/

public int doEndTag() throws JspTagException{

pageContext.getSession();

Boolean b = false;

List list = new ArrayList();

/*AcPermission p = new AcPermission();*/

/*JDBCHibernate jdbca = new JDBCHibernate();*/

try {

    /*list = jdbca.getHaveURLByUsernameList(user);*/

} catch (Exception e1) {

    // TODO Auto-generated catch block

    e1.printStackTrace();

}

for(int i = 0;i < list.size(); i++){

    /*p = (AcPermission) list.get(i);*/

    if(1==1) {//p.getUrl().trim().equals(url.trim())){

b = true;

//如果jsmethod属性不为null 则把超链接href改为调用js

if(jsmethod!=null){

    url = jsmethod;

}

}

}

JspWriter out = pageContext.getOut();

if(b){

    try {

//有权限 显示操作按钮

out.println("<a href='" +url+ "' class='regular'><img src='" + image + "' alt='" + alt +"' />" + value + "</a>");

} catch (IOException e) {

e.printStackTrace();

}

}

return super.SKIP_BODY;

}

    /* 释放资源*/

public void release(){

super.release();

}

public String getUser() {

return user;

}

public void setUser(String user) {

this.user = user;

}

public String getUrl() {

return url;

}

public void setUrl(String url) {

this.url = url;

}

public String getImage() {

return image;

}

public void setImage(String image) {

this.image = image;

}

public String getAlt() {

return alt;

}

public void setAlt(String alt) {

this.alt = alt;

}

public String getValue() {

return value;

}

public void setValue(String value) {

this.value = value;

}

public String getJsmethod() {

return jsmethod;

}

public void setJsmethod(String jsmethod) {

this.jsmethod = jsmethod;

}

}

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