jsp的自定义标签 控制jsp内容显示
引入方式示例
<%@ taglib prefix="fns" uri="/WEB-INF/tlds/fns.tld" %>
tld文件
<?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>
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;// abc.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; } }
在JSP中的使用方式
<bgt:hasUrlPerm link="abc.do"> <div>tttttttttttttttttest</div> </bgt:hasUrlPerm>
link=abc.do直接传入
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; } }