struts2 自定义标签

Struts2自定义标签
来自：

引用

http://www.blogjava.net/hawk8359/archive/2008/11/06/239093.html

声明标签
\WebRoot\WEB-INF\tangs.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>2.2.3</tlib-version>
    <jsp-version>1.2</jsp-version>
    <short-name>tangs</short-name>
    <uri>/tangs</uri>
    <display-name>"Tangs Tags"</display-name>
    <tag>
        <name>button</name>
        <tag-class>com.tag.button.ButtonTag</tag-class>
        <body-content>empty</body-content>
        <attribute>
            <name>name</name>
            <required>true</required>
            <rtexprvalue>true</rtexprvalue>
        </attribute>
    </tag>
</taglib>

定义标签接受到的值
\com\tag\button\Button.java

package com.tag.button;

public class Button {
    private String parent;

    public Button() {
    }

    public String getParent() {
        return parent;
    }

    public void setParent(String parent) {
        this.parent = parent;
    }

}

处理标签
\com\tag\button\Buttons.java

package com.tag.button;

import java.io.IOException;
import java.io.Writer;
import java.util.logging.Level;
import java.util.logging.Logger;

import org.apache.struts2.components.Component;

import com.opensymphony.xwork2.util.ValueStack;

public class Buttons extends Component {

    private String name;

    public String getName() {
        return name;
    }

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

    public Buttons(ValueStack arg0) {
        super(arg0);
    }

    @Override
    public boolean start(Writer arg0) {
        boolean result = super.start(arg0);
        try {
            StringBuilder str = new StringBuilder();
            boolean isValid = true;
            
            Button bt = (Button) this.getStack().findValue(name);
            isValid = bt != null ? true : false;
            
            if (isValid) {
                str.append("<input type=\"submit\" value=\"web.button.query\" method=\"search\"/>");
            }
            arg0.write(str.toString());
        } catch (IOException ex) {
            Logger.getLogger(Trees.class.getName()).log(Level.SEVERE, null, ex);
        }
        return result;
    }

}

调用标签
\com\tag\button\ButtonTag.java

package com.tag.button;

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 ButtonTag extends ComponentTagSupport {
    private static final long serialVersionUID = 1L;
    
    private String name;

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

    @Override
    public Component getBean(ValueStack arg0, HttpServletRequest arg1,
            HttpServletResponse arg2) {
        return new Buttons(arg0);
    }

    protected void populateParams() {
        super.populateParams();
        Buttons buttons = (Buttons) component;
        buttons.setName(name);
    }
}

测试
\com\tag\button\ButtonAction.java

package com.tag.button;

import com.opensymphony.xwork2.ActionSupport;

public class ButtonAction extends ActionSupport {

    private static final long serialVersionUID = 1L;

    private Button names;

    public Button getNames() {
        return names;
    }

    public void setNames(Button names) {
        this.names = names;
    }

    @Override
    public String execute() throws Exception {
        Button btn = new Button();
        btn.setParent("1");

        names = btn;
        return SUCCESS;
    }

}

备忘
接受对象数组的处理：

private Tree[] names;

    public Tree[] getNames() {
        return names;
    }

    public void setNames(Tree[] names) {
        this.names = names;
    }

    @Override
    public String execute() throws Exception {
        Tree[] trees = new Tree[5];
        names = trees;
        
        return SUCCESS;
    }

public boolean start(Writer arg0) {
        boolean result = super.start(arg0);
        
        try {
            StringBuilder str = new StringBuilder();
            boolean isValid = true;
            
            Tree[] trees = (Tree[]) this.getStack().findValue(name);
            isValid = trees != null ? true : false;
            if (isValid) {
                str.append("");
            }
            arg0.write(str.toString());
        } catch (IOException ex) {
            Logger.getLogger(Trees.class.getName()).log(Level.SEVERE, null, ex);
        }
        
        return result;
    }

jsp页面的调用：

<%@taglib uri="/tangs" prefix="tangs"%>
<html>
    <body>
        <tangs:button name="names"/>
    </body>
</html>