struts2 自定义tag标签

灰太狼 2022-08-27 14:59 227阅读 0赞

在项目中可能有很多相同的jsp页面表示功能，这时可以使用自定义的tag进行定义，渐少重复的工作量便于日后维护！

下面就基于struts2进行自定义标签的定义与实现：

首先：自定义类MyTag继承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>//这里进行页面的输出
    		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：指定标签类MyTagSupport继承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
    	// 设置bean值
    	protected void populateParams() {
    		System.out.println("开始设置参数！populateParams");
    		MyTag tag = (MyTag) getComponent();
    		tag.setName(name);
    		tag.setText(text);
    		tag.setDefaultValue("我就是默认值！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代码完成后，进行配置文件的编写，在WEB-INF/tlds 新建自定义文件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[我自定义的tag]]></description>
    		<name>myTag</name>
    		<tag-class>cookielogin.MyTagSupport</tag-class>
    		<body-content>JSP</body-content>
    		<attribute>
    			<description><![CDATA[这个是我自定义的标签]]></description>
    			<name>text</name>
    			<required>true</required>
    		</attribute>
    		<attribute>
    			<description><![CDATA[这个是我自定义的标签]]></description>
    			<name>name</name>
    			<required>true</required>
    		</attribute>
    		<attribute>
    			<description><![CDATA[这个是我自定义的标签]]></description>
    			<name>defaultValue</name>
    			<required>false</required>
    		</attribute>
    		<dynamic-attributes>false</dynamic-attributes>
    	</tag>
    	
    </taglib>

前提基础工作完成后，在页面引用：

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

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

访问页面后出现：

![SouthEast][]

基于struts2的自定义标签实现完毕！虽然功能很简单，但是基本功能已经实现，可以根据项目的实际需要进行编辑！

[SouthEast]: /images/20220823/d836c0e1fbb647dd8697aed542ffe5f6.png