Java自定义简单标签实例

package cn.com.liveuc.privilege.tag;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.Set;
import javax.servlet.jsp.JspException;
import javax.servlet.jsp.PageContext;
import javax.servlet.jsp.tagext.SimpleTagSupport;
import cn.com.liveuc.privilege.model.Privilege;
import cn.com.liveuc.privilege.model.Resource;
import cn.com.liveuc.privilege.model.Role;
import cn.com.liveuc.privilege.model.User;
/**
 *
 * @说明   自定义标签
 */
public class PerssionTag extends SimpleTagSupport {

 //自定义标签属性，用于标签传入参数
 private String uri;

 //接收标签传入的参数
 public void setUri(String uri) {
  this.uri = uri;
 }
 @Override
 public void doTag() throws JspException, IOException {
  //获取用户登陆后保存的Session
  PageContext page = (PageContext) this.getJspContext();
  User user = (User) page.getSession().getAttribute(“login”);
  //如果用户登陆
  if(user != null) {
   //用户登陆判断用户权限
   List list = new ArrayList();
   //获取用户的角色
   Set role = user.getRole();
   for(Role r:role) {
    //获取角色对应的权限
    Set privilege = r.getPrivilege();
    for(Privilege p:privilege) {
     //获取权限对应的资源
     Set res = p.getResource();
     for(Resource re:res) {
      list.add(re.getUri());
     }
    }
   }
   for(String ur:list) {
    //判断用户的权限
    if(ur.equals(uri)) {
     this.getJspBody().invoke(null); //有权限输出标签体内容
    }
   }
  }
 }
}

<taglib xmlns="http://java.sun.com/xml/ns/j2ee&quot; xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance&quot;
 version=”2.0″
 xsi:schemaLocation=”http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-jsptaglibrary_2_0.xsd”&gt;
 <![CDATA["To make it easier to access dynamic data;
                    the Apache Struts framework includes a library of custom tags.
                    The tags interact with the framework’s validation and internationalization features;
                    to ensure that input is correct and output is localized.
                    The Struts Tags can be used with JSP Fre来源gaodaimacom搞#^代%!码网eMarker or Velocity.”]]>
 “Struts Tags”
 2.2.3
 s
 /wxt
 
  per
  cn.com.liveuc.privilege.tag.PerssionTag
  scriptless
  
  
   uri
   true
   true