catedao.java

STRUTS2的入门 教程

package com.dao;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List;

import com.bean.Tcategories;
import com.db.DBHelper;

public class CateDAO {
	/**
	 * 
	 * 取得所有的类别
	 */
	public List<Tcategories> getAllCate() {
		List<Tcategories> list = new ArrayList<Tcategories>();
		String sql = "SELECT * FROM T_CATEGORIES";
		Statement stat = null;
		ResultSet rs = null;
		Connection conn = new DBHelper().getConn();
		try {
			stat = conn.createStatement();
			rs = stat.executeQuery(sql);
			while (rs.next()) {
				Tcategories tcategories = new Tcategories();
				tcategories.setCateid(rs.getInt(1));
				tcategories.setCatename(rs.getString(2));
				list.add(tcategories);
			}
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} finally {
			try {
				if (conn != null)
					conn.close();
				if (stat != null)
					stat.close();
				if (rs != null)
					rs.close();
			} catch (SQLException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
		return list;
	}
	
	/**
	 * 
	 * 取得对应类别ID的类别name
	 */
	public String getCateName(int cateid) {
		String catename = null;
		String sql = "SELECT CATE_NAME FROM T_CATEGORIES WHERE CATE_ID=?";
		PreparedStatement pstat = null;
		ResultSet rs = null;
		Connection conn = new DBHelper().getConn();
		try {
			pstat = conn.prepareStatement(sql);
			pstat.setInt(1, cateid);
			rs = pstat.executeQuery();
			while (rs.next()) {
				catename = rs.getString(1);
			}
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} finally {
			try {
				if (conn != null)
					conn.close();
				if (pstat != null)
					pstat.close();
				if (rs != null)
					rs.close();
			} catch (SQLException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
		return catename;
	}
	
	public static void main(String[] args) {
//		CateDAO cateDAO = new CateDAO();
//		List<Tcategories> list = cateDAO.getAllCate();
//		for (Tcategories tcategories : list) {
//			System.out.println("CateDAO.main()" + tcategories.getCateid());
//			System.out.println("CateDAO.main()" + tcategories.getCatename());
//		}
	}
}