bookutil.java

使用servlet写的简单网上书店

package utils;

import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.Vector;

import entity.Book;
import entity.ShoppingCart;

public class BookUtil {
	private Connection con;

	private PreparedStatement ps;

	private ResultSet rs;

	public BookUtil(Connection con) {
		this.con = con;
	}

	public void displayBook(Book book,PrintWriter out) {
		try {
			ps = con.prepareStatement("select * from book");
			rs=ps.executeQuery();
			while (rs.next()) {
				out.println(rs.getInt(1)
						+ "      "
						+ rs.getString(2)
						+ "      "
						+ "<input type=\"checkbox\" name=\"books\" value=\""
						+ rs.getInt(1) + "\"><br>");
			}
		} catch (SQLException e) {
			e.printStackTrace();
		} finally {
			if (ps != null) {
				try {
					ps.close();
				} catch (SQLException e) {
					e.printStackTrace();
				}
			}
		}
	}
	
	public void displayEditBook(Book book,PrintWriter out) {
		try {
			ps = con.prepareStatement("select * from book");
			rs=ps.executeQuery();
			while (rs.next()) {
				out.println(rs.getInt(1)
						+ "&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;"
						+ rs.getString(2)
						+ "&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;"
						+ "<input type=\"Button\" name=\"editbook\" value=\"编辑\"><br>");
			}
		} catch (SQLException e) {
			e.printStackTrace();
		} finally {
			if (ps != null) {
				try {
					ps.close();
				} catch (SQLException e) {
					e.printStackTrace();
				}
			}
		}
	}
	
	public void getList(String[] books,ShoppingCart cart){
		try {
			ps=con.prepareStatement("select * from book where id in ("+this.getIdArray(books)+")");
			rs=ps.executeQuery();
			
			while(rs.next()){
				cart.addBook(new Book(rs.getInt(1),rs.getString(2)));
			}
		} catch (SQLException e) {
			e.printStackTrace();
		} finally{
			try {
				if(rs!=null){rs.close();}
				if(ps!=null){ps.close();}
			} catch (SQLException e) {
				e.printStackTrace();
			}
		}
	}
	
	public void getByName(String bookName,PrintWriter out){
		try {
			ps=con.prepareStatement("select * from book where name like '%"+bookName+"'");
			rs=ps.executeQuery();
			while(rs.next()){
				out.println("<br>"+rs.getInt(1)
						+ "&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;"
						+ rs.getString(2)
						+ "&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;"
						+ "<input type=\"checkbox\" name=\"books\" value=\""
						+ rs.getInt(1) + "\">");
			}
		} catch (SQLException e) {
			e.printStackTrace();
		} finally {
			if (ps != null) {
				try {
					ps.close();
				} catch (SQLException e) {
					e.printStackTrace();
				}
			}
		}
	}
	
	public void addBook(Book book){
		try {
			ps=con.prepareStatement("insert into book(name,price) values(?,?)");
			ps.setString(1, book.getName());
			ps.setDouble(2, book.getPrice());
			ps.executeUpdate();
		} catch (SQLException e) {
			e.printStackTrace();
		} finally {
			if (ps != null) {
				try {
					ps.close();
				} catch (SQLException e) {
					e.printStackTrace();
				}
			}
		}
	}
	public void deleteBook(String[] books){
		try {
			ps=con.prepareStatement("delete from book where id in ("+this.getIdArray(books)+")");
			ps.executeUpdate();
		} catch (SQLException e) {
			e.printStackTrace();
		} finally {
			if (ps != null) {
				try {
					ps.close();
				} catch (SQLException e) {
					e.printStackTrace();
				}
			}
		}
	}
	public void editBook(String[] books){
		ps=con.prepareStatement("update book set name=?,price=? where id="+books[i]);

	}
	public String getIdArray(String[] books){
		String idStr="";
		for(String s:books){
			idStr=idStr+s+",";
		}
		String result = idStr.substring(0,idStr.lastIndexOf(","));	
        System.out.println(result);
		return result;
	}
}