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);
}
}*/
}