Java 数据库操作之Dao类

package Dao;

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

import bean.Pair;
import util.DBConnection;

public class PairDao {
        
    public void Addpair(Pair pair) {
        java.sql.Connection connection = DBConnection.getConnection();
        String sql = "insert into pre_info values " + "('" + 
                pair.getId() + 
        "','" + pair.getUser() + 
        "','" + pair.getFollow() + "')";
        java.sql.PreparedStatement pstmt = DBConnection.getPreparedStatement(connection, sql);
        //System.out.println(sql);
        try {
            Statement stmt = connection.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_READ_ONLY);
            stmt.executeUpdate(sql);
        }
        catch (SQLException e) {
            e.printStackTrace();
        }
        finally {
            DBConnection.close(connection, pstmt, null);
        }
    }
    
    
    public List<Pair> QueryUserPair(Pair pair) {
        java.sql.Connection connection = DBConnection.getConnection();
        String sql = "select * from pre_id where user=" + pair.getUser();
        java.sql.PreparedStatement pstmt = DBConnection.getPreparedStatement(connection, sql);
        List<Pair> pairlist = new ArrayList<Pair>();
        System.out.println(sql);
        try {
            Statement stmt = connection.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_READ_ONLY);
            java.sql.ResultSet rs = stmt.executeQuery(sql);
            while (rs.next()) {
                Pair pair1 = new Pair();
                pair1.setId(rs.getInt(1));
                pair1.setUser(rs.getString(2));
                pair1.setFollow(rs.getString(3));
                pairlist.add(pair1);
                System.out.println(pair1);
            }
            rs.last();
        }
        catch (SQLException e) {
            e.printStackTrace();
        }
        finally {
            DBConnection.close(connection, pstmt, null);
        }
        return pairlist;
    }

    /*
     * 
     * 
     * public void Addinfo_id(Info info) {
        java.sql.Connection connection = DBConnection.getConnection();
        String sql = "insert into pre_id values " + "('" + info.getId() + "','" + info.getState() + "','" + info.getNowid() + ")";
        java.sql.PreparedStatement pstmt = DBConnection.getPreparedStatement(connection, sql);
        System.out.println(sql);
        try {
            Statement stmt = connection.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_READ_ONLY);
            stmt.executeUpdate(sql);
        }
        catch (SQLException e) {
            e.printStackTrace();
        }
        finally {
            DBConnection.close(connection, pstmt, null);
        }
    }
    public void UpdateInfo(Pair info) {
        java.sql.Connection connection = DBConnection.getConnection();
        String sql = "update pre_info set" + " var_id='" + info.getVar_id() + "',var_time='" + info.getVar_time() + "',var_site='" + info.getVar_site()+ "',var_infoid='" + info.getVar_infoid() + "'";
        java.sql.PreparedStatement pstmt = DBConnection.getPreparedStatement(connection, sql);
        System.out.println(sql);
        try {
            Statement stmt = connection.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_READ_ONLY);
            stmt.executeUpdate(sql);
        }
        catch (SQLException e) {
            e.printStackTrace();
        }
        finally {
            DBConnection.close(connection, pstmt, null);
        }
    }
        public void DeleteInfo(Pair info) {
        java.sql.Connection connection = DBConnection.getConnection();
        String sql = "delete from pre_info where var_id=" + info.getId();
        java.sql.PreparedStatement pstmt = DBConnection.getPreparedStatement(connection, sql);
        System.out.println(sql);
        try {
            Statement stmt = connection.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_READ_ONLY);
            stmt.executeUpdate(sql);
        }
        catch (SQLException e) {
            e.printStackTrace();
        }
        finally {
            DBConnection.close(connection, pstmt, null);
        }
    }
    public Pair QueryPair(Pair pair) {
        java.sql.Connection connection = DBConnection.getConnection();
        String sql = "select * from pre_id where user=" + pair.getUser();
        java.sql.PreparedStatement pstmt = DBConnection.getPreparedStatement(connection, sql);
        System.out.println(sql);
        Pair pair1 = new Pair();
        try {
            Statement stmt = connection.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_READ_ONLY);
            java.sql.ResultSet rs = stmt.executeQuery(sql);
            while (rs.next()) {
                pair1.setId(rs.getInt(1));
                pair1.setUser(rs.getString(2));
                pair1.setFollow(rs.getString(3));
            }
            rs.last();
        }
        catch (SQLException e) {
            e.printStackTrace();
        }
        finally {
            DBConnection.close(connection, pstmt, null);
        }
        return pair1;
    }
    public Info QueryBook(Info info) {
        java.sql.Connection connection = DBConnection.getConnection();
        String sql = "select * from pre_id where id=" + info.getId();
        java.sql.PreparedStatement pstmt = DBConnection.getPreparedStatement(connection, sql);
        System.out.println(sql);
        Info info1 = new Info();
        try {
            Statement stmt = connection.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_READ_ONLY);
            java.sql.ResultSet rs = stmt.executeQuery(sql);
            while (rs.next()) {
                info1.setId(rs.getString(1));
                info1.setState(rs.getString(2));
                info1.setNowid(rs.getString(3));
            }
            rs.last();
        }
        catch (SQLException e) {
            e.printStackTrace();
        }
        finally {
            DBConnection.close(connection, pstmt, null);
        }
        return info1;
    }*/

    /*public List<Book> QueryBook1(Book book) {
        java.sql.Connection connection = DBConnection.getConnection();
        String sql = "select * from Book where bookname LIKE '%" + book.getBookname() + "%'";
        java.sql.PreparedStatement pstmt = DBConnection.getPreparedStatement(connection, sql);
        System.out.println(sql);
        List<Book> booklist = new ArrayList<Book>();
        Book book1 = new Book();
        try {
            Statement stmt = connection.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_READ_ONLY);
            java.sql.ResultSet rs = stmt.executeQuery(sql);
            while (rs.next()) {
                book1.setBookname(rs.getString(1));
                book1.setBooknumber(rs.getString(2));
                book1.setPressname(rs.getString(3));
                book1.setAuthor(rs.getString(4));
                book1.setTranslator(rs.getString(5));
                book1.setPrice(rs.getString(6));
                book1.setDate(rs.getString(7));
                book1.setBorrowcount(Integer.parseInt(rs.getString(8)));
                booklist.add(book1);
                // System.out.println(book);
            }
            rs.last();
        }
        catch (SQLException e) {
            e.printStackTrace();
        }
        finally {
            DBConnection.close(connection, pstmt, null);
        }
        return booklist;
    }

    public List<Book> QueryAllBook() {
        java.sql.Connection connection = DBConnection.getConnection();
        String sql = "select * from Book order by borrowcount desc";
        java.sql.PreparedStatement pstmt = DBConnection.getPreparedStatement(connection, sql);
        List<Book> booklist = new ArrayList<Book>();
        System.out.println(sql);
        try {
            Statement stmt = connection.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_READ_ONLY);
            java.sql.ResultSet rs = stmt.executeQuery(sql);
            while (rs.next()) {

                Book book = new Book();
                book.setBookname(rs.getString(1));
                book.setBooknumber(rs.getString(2));
                book.setPressname(rs.getString(3));
                book.setAuthor(rs.getString(4));
                book.setTranslator(rs.getString(5));
                book.setPrice(rs.getString(6));
                book.setDate(rs.getString(7));
                book.setBorrowcount(Integer.parseInt(rs.getString(8)));
                booklist.add(book);
                System.out.println(book);
            }
            rs.last();
        }
        catch (SQLException e) {
            e.printStackTrace();
        }
        finally {
            DBConnection.close(connection, pstmt, null);
        }
        return booklist;
    }

    public void UpdateBookBorrowCount(Book book) {
        java.sql.Connection connection = DBConnection.getConnection();
        String sql = "update Book set " + "borrowcount=" + book.getBorrowcount() + " where booknumber='" + book.getBooknumber() + "'";
        java.sql.PreparedStatement pstmt = DBConnection.getPreparedStatement(connection, sql);
        System.out.println(sql);
        try {
            Statement stmt = connection.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_READ_ONLY);
            stmt.executeUpdate(sql);
        }
        catch (SQLException e) {
            e.printStackTrace();
        }
        finally {
            DBConnection.close(connection, pstmt, null);
        }
    }*/
}