自定义标签使用

 

在jsp页面使用此自定义标签

 

1 创建自定义标签类

public class UserInfoTag extends TagSupport {

    private UserInfo user;

    @Override

    public int doStartTag() throws JspException {
	HttpServletRequest request = (HttpServletRequest)pageContext.getRequest();
	HttpServletResponse response = (HttpServletResponse)pageContext.getResponse();
	HttpSession session = request.getSession();

        try {
            JspWriter out = this.pageContext.getOut();
            if(user == null) {
                out.println("No UserInfo Found...");
                return SKIP_BODY;
            }
            out.println("<table width='500px' border='1' align='center'>");
            out.println("<tr>");
            out.println("<td width='20%'>Username:</td>");
            out.println("<td>" + user.getUserName() + "</td>");
            out.println("</tr>");
            out.println("<tr>");
            out.println("<td>Age:</td>");
            out.println("<td>" + user.getAge() + "</td>");
            out.println("</tr>");
            out.println("<tr>");
            out.println("<td>Email:</td>");
            out.println("<td>" + user.getEmail() + "</td>");
            out.println("</tr>");
            out.println("</table>");

        } catch(Exception e) {
            throw new JspException(e.getMessage());
        }
        return SKIP_BODY;
    }
 
    //getter and setters
    public UserInfo getUser() {
        return user;
    }
    public void setUser(UserInfo user) {
        this.user = user;
    }
}

 

2 在Web-Inf创建标签库描述文件.tdl(Tag Library Description)

 

 

<?xml version="1.0" encoding="UTF-8"?>
<taglib version="2.0" xmlns="http://java.sun.com/xml/ns/j2ee"
 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee web-jsptaglibrary_2_0.xsd">
<tlib-version>1.0</tlib-version>
<jsp-version>2.0</jsp-version>
<short-name>cc</short-name>
<uri>/mytaglib</uri>
<tag>
    <!—指定标签类文件的全路径 -->
    <name>showUserInfo</name>
    <!—指定标签类文件的全路径 -->
    <tag-class>com.mytags.UserInfoTag</tag-class>
    <!--如果不需要标签体则设置empty，反之设定jsp -->
    <body-content>empty</body-content>
    <!—设定属性(如果有的话) -->
    <attribute>
         <!—指定标签名 -->
        <name>user</name>
         <!—是否是必须，如果非必须没设置则为空 -->
         <required>false</required>
         <!—是否可在属性中使用表达式 -->
         <rtexprvalue>true</rtexprvalue>

    </attribute>
 </tag>
</taglib>

 

 

 

3 配置web.xml

<jsp-config>
    <taglib>
        <taglib-uri>/mytaglib</taglib-uri>
        <taglib-location>/WEB-INF/mytaglib.tld</taglib-location>
    </taglib>
</jsp-config>

 

 

 

4 页面中使用

 

<%@ taglib uri="/mytaglib" prefix="cc"%>
<%
    UserInfo user = new UserInfo();
    user.setUserName("Xuwei");
    user.setAge(33);
    user.setEmail("[email protected]");
    pageContext.setAttribute("userinfo", user);  
%>

<cc:showUserInfo user="${pageScope.userinfo }" />