java中结合struts2自定义标签的使用

java中结合struts2自定义标签的使用

一、建立一个继承于SimpleTagSupport类实现它的doTag方法

package com.xiangshang.tag;

import java.io.IOException;
import java.util.List;

import javax.servlet.jsp.JspException;
import javax.servlet.jsp.PageContext;
import javax.servlet.jsp.tagext.SimpleTagSupport;

import com.opensymphony.xwork2.ActionContext;
import com.opensymphony.xwork2.util.ValueStack;

public class FunctionTag extends SimpleTagSupport {
    
    private String value;

    private String name;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getValue() {
        return value;
    }

    public void setValue(String value) {
        this.value = value;
    }

    @SuppressWarnings("unchecked")
    @Override
    public void doTag() throws JspException, IOException {
        StringBuilder sb = new StringBuilder();
        PageContext pageContext = (PageContext) this.getJspContext();
        List<String> functions = (List<String>) pageContext.getSession()
                .getAttribute("functions");
        ValueStack vs = ActionContext.getContext().getValueStack();
        String str = (String) vs.findValue(name);
        for (String s : functions) {
            if (s.equals(str)) {
                sb.append("<a href="javascript:alert('有权限')">")
                        .append(value).append("</a>");
                break;
            }
        }
        if (sb.length()==0) {
            sb.append("<a href="javascript:alert('没权限！！')">")
                    .append(value).append("</a>");
        }
        pageContext.getOut().print(sb);
    }
}

　　为了测试方便本人在建立了session监听器来存储function：

　　　

package com.xiangshang.listener;

import java.util.ArrayList;
import java.util.List;

import javax.servlet.ServletContext;
import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
import javax.servlet.http.HttpSessionEvent;
import javax.servlet.http.HttpSessionListener;

import org.springframework.web.context.WebApplicationContext;
import org.springframework.web.context.support.WebApplicationContextUtils;

import com.xiangshang.service.UserService;

public class MySessionListener implements HttpSessionListener{
    @Override
    public void sessionCreated(HttpSessionEvent hse) {
        System.out.println("Zhangqy Session Created");
        List<String> functions= new ArrayList<String>();
        functions.add("添加人信息");
        functions.add("删除人信息");
        functions.add("查看人信息");
        functions.add("修改人信息");
        hse.getSession().setAttribute("functions",functions);
    }

    @Override
    public void sessionDestroyed(HttpSessionEvent hse) {
    }


}

二、在WEB-INF下创建tld 文件：xiangshang.tld

　

　<?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>x</short-name>
 <uri>/xiangshang-tags</uri>
 <display-name>xiangshang tags</display-name>
 <tag>
  <name>a</name>
  <tag-class>com.xiangshang.tag.FunctionTag</tag-class>
  <body-content>empty</body-content>  
  <attribute>
   <name>name</name>
   <required>true</required>
   <rtexprvalue>true</rtexprvalue>
   <type>java.lang.String</type> 
  </attribute>  
   <attribute>
   <name>value</name>
   <required>true</required>
   <rtexprvalue>true</rtexprvalue>
   <type>java.lang.String</type> 
  </attribute> 
 </tag>
 </taglib>

三、在jsp界面中首先倒入自定义的标签库 ：

<%@ taglib uri="/xiangshang-tags" prefix="x" %>

四、接下来就是开始使用自定义标签了：

<x:a name="添加人信息" value="添加人信息"/>