struts2 自定義tag標籤

在項目中可能有不少相同的jsp頁面表示功能，這時可使用自定義的tag進行定義，漸少重複的工做量便於往後維護！

下面就基於struts2進行自定義標籤的定義與實現：

首先：自定義類MyTag繼承struts2的Component

package cookielogin;

import java.io.IOException;
import java.io.Writer;

import org.apache.struts2.components.Component;

import com.opensymphony.xwork2.util.ValueStack;

public class MyTag extends Component {
	private ValueStack stack;
	private String text;
	private String name;
	private String defaultValue;

	@Override
	public boolean start(Writer writer) {

<span style="white-space:pre">		</span>//這裏進行頁面的輸出
		try {
			writer.write("<h1>" + this.text + "</h1>");
			writer.write("<input name='text' value=");
			writer.write(this.getName());
			writer.write(" name='" + this.getName() + "'>");
		} catch (IOException e) {
			e.printStackTrace();
		}
		return super.start(writer);
	}

	public MyTag(ValueStack stack) {
		super(stack);
		this.stack = stack;
	}

	public ValueStack getStack() {
		return stack;
	}

	public void setStack(ValueStack stack) {
		this.stack = stack;
	}

	public String getText() {
		return text;
	}

	public void setText(String text) {
		this.text = text;
	}

	public String getName() {
		return name;
	}

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

	public String getDefaultValue() {
		return defaultValue;
	}

	public void setDefaultValue(String defaultValue) {
		this.defaultValue = defaultValue;
	}

}

2：指定標籤類MyTagSupport繼承ComponentTagSupport

package cookielogin;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.struts2.components.Component;
import org.apache.struts2.views.jsp.ComponentTagSupport;

import com.opensymphony.xwork2.util.ValueStack;

public class MyTagSupport extends ComponentTagSupport {

	private static final long serialVersionUID = 3586338980857274359L;

	String name;
	String text;

	@Override
	public Component getBean(ValueStack stack, HttpServletRequest req,
			HttpServletResponse res) {
		return new MyTag(stack);
	}

	@Override
	// 設置bean值
	protected void populateParams() {
		System.out.println("開始設置參數！populateParams");
		MyTag tag = (MyTag) getComponent();
		tag.setName(name);
		tag.setText(text);
		tag.setDefaultValue("我就是默認值！咋滴！！");
	}

	public String getName() {
		return name;
	}

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

	public String getText() {
		return text;
	}

	public void setText(String text) {
		this.text = text;
	}

}

java代碼完成後，進行配置文件的編寫，在WEB-INF/tlds 新建自定義文件tags-custom.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>2.0</tlib-version>
	<jsp-version>1.2</jsp-version>
	<short-name>ctags</short-name>
	<uri>http://www.cml.com/tags-custom</uri>
	<description>
	<![CDATA[
		   <p>This is custom tag.</p>
	]]>
	</description>

	<tag>
		<description><![CDATA[我自定義的tag]]></description>
		<name>myTag</name>
		<tag-class>cookielogin.MyTagSupport</tag-class>
		<body-content>JSP</body-content>
		<attribute>
			<description><![CDATA[這個是我自定義的標籤]]></description>
			<name>text</name>
			<required>true</required>
		</attribute>
		<attribute>
			<description><![CDATA[這個是我自定義的標籤]]></description>
			<name>name</name>
			<required>true</required>
		</attribute>
		<attribute>
			<description><![CDATA[這個是我自定義的標籤]]></description>
			<name>defaultValue</name>
			<required>false</required>
		</attribute>
		<dynamic-attributes>false</dynamic-attributes>
	</tag>
	
</taglib>

前提基礎工做完成後，在頁面引用：

<%@taglib prefix="d" uri="http://www.cml.com/tags-custom"%>
使用：

<d:myTag text="hhahh" name="sdfsd"></d:myTag>

訪問頁面後出現：

基於struts2的自定義標籤實現完畢！雖然功能很簡單，可是基本功能已經實現，能夠根據項目的實際須要進行編輯！