cputag.java

java编写的电子商务网站源码,做的一个电脑直销网站,后台数据库使用的是MS SQL2000 Server,数据流的流向主要有两个方向

package tag;

import java.io.*;
import java.util.*;
import java.sql.*;
import javax.servlet.jsp.*;
import javax.servlet.jsp.tagext.*;
import javax.servlet.http.*;

public class CpuTag extends BodyTagSupport {

	private int trend = 0;
	private int begin = 1;
	private int index = 0;
	private boolean cont = false;
	private ResultSet rs = null;

	public ResultSet getResult() {
		return this.rs;
	}

	public void setResult(ResultSet rs) {
		this.rs = rs;
	}

	public int getBegin() {
		return this.begin;
	}

	public void setBegin(int begin) {
		this.begin = begin;
	}

	public int doStartTag() throws JspTagException {
		setHeader();
		try {
			index = 0;
			cont = true;
			rs.absolute(begin);
		}
		catch (SQLException sqle) {
			sqle.printStackTrace();
		}
		return BodyTag.EVAL_BODY_BUFFERED;
	}

	public int doAfterBody() {
		if(cont){
			setValue();
			index++;
			try {
				cont = (rs.next() && index<7);
				return BodyTag.EVAL_BODY_BUFFERED;
			}
			catch (SQLException sqle) {
				return BodyTag.SKIP_BODY;
			}
		}
		else
			return BodyTag.SKIP_BODY;	
	}

	public int doEndTag() throws JspTagException {
		if (bodyContent != null) {
			try {
				bodyContent.writeOut(bodyContent.getEnclosingWriter());
			}
			catch (IOException ioe) {}
		}
		return BodyTag.EVAL_PAGE;
	}

	private void setHeader() {
		pageContext.setAttribute("id", "序号");
		pageContext.setAttribute("type", "类型");
		pageContext.setAttribute("manufactor", "生产厂商");
		pageContext.setAttribute("name", "型号");
		pageContext.setAttribute("speed", "主频(MHz)");
		pageContext.setAttribute("price", "价格(元)");
		pageContext.setAttribute("trend", "涨跌");
	}

	private void setValue() {
		try {
			pageContext.setAttribute("id", String.valueOf(rs.getInt(1)));
			pageContext.setAttribute("type", String.valueOf(rs.getInt(2)));
			pageContext.setAttribute("manufactor", rs.getString(3));
			pageContext.setAttribute("name", rs.getString(4));
			pageContext.setAttribute("speed", String.valueOf(rs.getInt(5)));
			pageContext.setAttribute("price", String.valueOf(rs.getInt(6)));

			switch (rs.getInt(7)) {
				case -1 :
					pageContext.setAttribute(
						"trend",
						"<font color='green'>下跌</font>");
					break;
				case 0 :
					pageContext.setAttribute(
						"trend",
						"<font color='blue'>持平</font>");
					break;
				case 1 :
					pageContext.setAttribute(
						"trend",
						"<font color='red'>上涨</font>");
					break;
			}
		}
		catch (SQLException sqle) {}
	}
}