package book.slider;

import java.sql.*;
import java.util.Vector;

import javax.servlet.ServletException;
import javax.servlet.http.*;

public class pageServlet extends HttpServlet {
	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, java.io.IOException {
		// 獲得請求中page的值
		String currPage = request.getParameter("page");
		int number = 1;
		try {
			number = Integer.parseInt(currPage);// 將String轉化為int型
		} catch (Exception e) {
			number = 1;
		}
		// 設置每頁顯示10條記錄
		int PAGE_SIZE = 10;
		// 查詢所有記錄的sql語句
		String sql = "select * from student";
		// 執行查詢返回記錄集對象
		ResultSet rs = DbManager.getResultSet(sql);
		// 定義保存數據的向量
		Vector vData = new Vector();
		try {
			// 將游標移動到當前頁的第一條記錄上
			rs.absolute((number - 1) * PAGE_SIZE + 1);
			// 定義Student實體類
			StudentEO student = null;
			int i = 0;
			// 循環記錄集,將記錄集中的數據保存到實體類中
			while (i < PAGE_SIZE) {
				student = new StudentEO();
				student.setId(rs.getInt("STUDENT_ID"));
				student.setStudentName(rs.getString("STUDENT_NAME"));
				student.setStudentClass(rs.getString("STUDENT_CLASS"));
				// 將保存數據后的student實體類保存到向量中
				vData.add(student);
				rs.next();
				i++;
			}
			// 最后釋放Connection對象
			DbManager.releaseConnection();
		} catch (SQLException e) {
			e.printStackTrace();
		}
		// 設置返回數據為xml格式
		response.setContentType("text/xml");
		java.io.PrintWriter out = response.getWriter();
		// 調用parasToXML方法組織XML數據
		out.print(parasToXML(vData));
	}

	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, java.io.IOException {

		doPost(request, response);
	}

	public String parasToXML(Vector v) {
		StringBuffer buf = new StringBuffer();
		// 將向量中的數據組織成XML數據
		buf.append("<?xml version=\"1.0\" encoding=\"UTF-8\"?>");
		buf.append("<students>");
		for (int i = 0; i < v.size(); i++) {
			StudentEO s = (StudentEO) v.get(i);
			buf.append("<student>");
			buf.append("<id>" + s.getId() + "</id>");
			buf.append("<name>" + s.getStudentName() + "</name>");
			buf.append("<class>" + s.getStudentClass() + "</class>");
			buf.append("</student>");
		}
		buf.append("</students>");
		return buf.toString();
	}
}