usebeantag.java

JavaWeb高级特性书中源代码

package org.it315;
import javax.servlet.jsp.JspException;
import javax.servlet.jsp.tagext.TagSupport;
public class UseBeanTag extends TagSupport
{
	private String name;
	private String type;
	private String scope;
	private int iScope;
	public void setName(String name) 
	{
		this.name = name;
	}
	public void setType(String type) 
	{
		this.type = type;
	}
	public void setScope(String scope)
	{
		this.scope = scope;
	}
	public int doStartTag() throws JspException 
	{
		if("page".equals(scope))
		{
			iScope = pageContext.PAGE_SCOPE;
		}
		else if("request".equals(scope))
		{
			iScope = pageContext.REQUEST_SCOPE;
		}
		else if("session".equals(scope))
		{
			iScope = pageContext.SESSION_SCOPE;
		}
		else if("application".equals(scope))
		{
			iScope = pageContext.APPLICATION_SCOPE;
		}
		try 
		{
			Object obj = Class.forName(type).newInstance();//实例化引入的类
			pageContext.setAttribute(name, obj, iScope);
		} 
		catch (InstantiationException e) 
		{	
			e.printStackTrace();
		} 
		catch (IllegalAccessException e) 
		{
			e.printStackTrace();
		} 
		catch (ClassNotFoundException e)
		{	
			e.printStackTrace();
		}
		return EVAL_BODY_INCLUDE;
	}
}