jsp自訂標籤庫實現資料列表顯示

最後更新：2018-12-05 來源：互聯網

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文章標題: jsp自訂標籤庫實現資料列表顯示

作者： javaboy2012
Email：yanek@163.com
qq: 1046011462

1. 定義標籤庫類 UserListTag.java

package com.yanek.cms.tag;

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

import javax.servlet.jsp.JspException;
import javax.servlet.jsp.tagext.BodyTagSupport;

import com.yanek.cms.vo.UserInfo;

public class UserListTag extends BodyTagSupport {

private String name;// 一個屬性名稱
private Iterator it;// 要迭代的對象
private int cateid; // 使用者類別id

@Override
public int doEndTag() throws JspException {
  try {
   if (bodyContent != null) {
    bodyContent.writeOut(bodyContent.getEnclosingWriter());
   }
  } catch (IOException e) {
   e.printStackTrace();

}
return EVAL_PAGE;
}

@Override
public int doStartTag() throws JspException {

  //這雷根據使用者類型,構造不同的列表資料,實現可以根據資料庫擷取
  List<UserInfo> users = new ArrayList<UserInfo>();
  if (cateid == 1) {
   users.add(new UserInfo("張三", 20, "Zhangsan@163.com"));

   users.add(new UserInfo("李四", 30, "Lisi@sina.com"));
  } else {
   users.add(new UserInfo("王五", 33, "Wangwu@qq.com"));
   users.add(new UserInfo("趙六", 33, "zhaoliu@qq.com"));
  }
  it = users.iterator();

if (it == null) {
return SKIP_BODY;

  } else {
   return continueNext();
  }
}

private int continueNext() {
  if (it.hasNext()) {
   pageContext.setAttribute(name, it.next(), pageContext.PAGE_SCOPE);
   return EVAL_BODY_TAG;
  } else {

return SKIP_BODY;
}
}

@Override
public int doAfterBody() {
return continueNext();
}

public String getName() {
return name;
}

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

public int getCateid() {
return cateid;
}

public void setCateid(int cateid) {
this.cateid = cateid;
}

}

2. 在WEB-INF目錄下建立標籤庫描述檔案my_cms_tag.tld：

my_cms_tag.tld

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

<!DOCTYPE taglib PUBLIC "-//Sun Microsystems, Inc.//DTD JSP Tag Library 1.1//EN" "http://java.sun.com/j2ee/dtds/web-jsptaglibrary_1_1.dtd">
<taglib>
<tlibversion>1.0</tlibversion>
<jspversion>1.0</jspversion>
<shortname>cms</shortname>
<uri>http://www.58tech.cn/mystruts/tags-cms</uri>

<tag>

<name>userListTag</name>

<tag-class>com.yanek.cms.tag.UserListTag</tag-class>

<body-content>jsp</body-content>

      <variable>
        
        <name-from-attribute>name</name-from-attribute>
        <variable-class>com.yanek.cms.vo.UserInfo</variable-class>
        <declare>true</declare>
        <scope>NESTED</scope>
      </variable>

       <attribute>
        <name>name</name>
        <required>true</required>
       </attribute>

       <attribute>
        <name>cateid</name>
        <required>true</required>
       </attribute>

</tag>

</taglib>

3. web.xml配置

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5"
xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
<welcome-file-list>
    <welcome-file>index.jsp</welcome-file>
</welcome-file-list>

<taglib>
      <taglib-uri>/tags/my-cms</taglib-uri>
      <taglib-location>/WEB-INF/my_cms_tag.tld</taglib-location>
</taglib>

</web-app>

4. jsp調用

<%@ page language="java" import="java.util.*,com.yanek.cms.vo.*" pageEncoding="UTF-8"%>
<%@ taglib uri="/tags/my-cms" prefix="myTag" %>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
    <base href="<%=basePath%>">

    <title>My JSP 'test.jsp' starting page</title>

<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">

</head>

<body>

<table width='500px' border='1' align='center'>

<tr>

<td width='20%'>UserName</td>

<td>Email</td>

    </tr>

<myTag:userListTag name="user_info1" cateid="1">

       <tr>

</tr>

</myTag:userListTag>
</table>

<hr>

<tr>

<td width='20%'>UserName</td>

<td>Email</td>

</tr>

<myTag:userListTag name="user_info2" cateid="2">

</td>
</tr>
</myTag:userListTag>
</table>

</body>
</html>

實體類定義

package com.yanek.cms.vo;

public class UserInfo {

private int age;
private String userName;
private String email;
public int getAge() {
  return age;
}
public void setAge(int age) {
  this.age = age;
}
public String getUserName() {
  return userName;
}
public void setUserName(String userName) {
  this.userName = userName;
}
public String getEmail() {
  return email;
}
public void setEmail(String email) {
  this.email = email;
}
public UserInfo(String userName,int age, String email) {
  super();
  this.age = age;
  this.userName = userName;
  this.email = email;
}

public UserInfo() {

}

運行效果; http://127.0.0.1:8080/TestCMS/page/userlist.jsp

: http://download.csdn.net/detail/5iasp/5118606 (不需要積分)

本文章原先以中文撰寫並發佈於 aliyun.com，亦設英文版本，僅作資訊用途。本網站不對文章的準確性，完整性或可靠性或其任何翻譯作出任何明示或暗示的陳述或保證。如對該文章有任何疑慮或投訴，請傳送電郵至 info-contact@alibabacloud.com 並提供相關疑慮或投訴的詳細說明。職員會於 5 個工作天內與您聯絡，一經驗證之後，即會刪除該侵權內容。

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