jdbc操作數據庫的代碼案例

下面直接貼代碼吧，實體類我就不貼了

獲取數據庫連接的工具類

package util;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

public class DBUtil {

    // 驅動名稱 這裏是sqlserver驅動
    private static final String DRIVER = "com.microsoft.sqlserver.jdbc.SQLServerDriver";

    // 數據庫地址 127.0.0.1表示本地，
    //1433是sqlserver默認的端口，food_db是要鏈接的數據庫
    private static final String URL = "jdbc:sqlserver://127.0.0.1:1433;databasename=food_db";

    // 用戶名
    private static final String USER = "admin";

    // 密碼
    private static final String PASS = "123456";

    //在靜態塊中加載數據庫連接驅動
    static {
        try {
            Class.forName(DRIVER);
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }
    }

    //得到數據庫連接的方法
    public static Connection getConnection() {
        Connection conn = null;
        try {
            conn = DriverManager.getConnection(URL, USER, PASS);
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return conn;
    }

    //關閉連接的方法
    public static void closeAll(Connection conn, Statement stmt, ResultSet rs) {
        try {
            if (rs != null)
                rs.close();
            if (stmt != null)
                stmt.close();
            if (conn != null)
                conn.close();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    //測試 打印下數據庫連接是否正常得到
    public static void main(String[] args) {
        System.out.println(getConnection());
    }

}

//通過JdbcTemplate操作的方式

package dao.impl;

import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.Date;
import java.util.List;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.core.RowMapper;
import util.DBUtil;
import bean.Account;
import bean.Trade;

public class BankDaoImpl  {

    //得到JdbcTemplate對象，調用DBUtil.getDataSource()得到數據庫連接
    private JdbcTemplate temp = new JdbcTemplate(DBUtil.getDataSource());

    //查詢指定條件的數據，Account實體類我就不寫了
    public Account login(Account a) {

        //需要執行的sql語句 下面的Account實體類我就不寫了
        String sql = "select * from account where AccountID=? and password=? ";

        List list = this.temp.query(sql, new Object[] { a.getAccountID(),a.getPassword() }, 
                new RowMapper() {
                    public Object mapRow(ResultSet rs, int arg1) throws SQLException {
                        Account a = new Account();
                        a.setRemaining(rs.getDouble("remaining"));//獲取字段名爲remaining的數據
                        a.setAccountID(rs.getString("accountid"));//獲取字段名爲accountid的數據
                        a.setPassword(rs.getString("password"));//獲取字段名爲password的數據
                        return a;
                    }
                });

        if (list.size() > 0){
            return (Account) list.get(0);
        }

        return null;
    }

    //查詢多個對象方法，Trade跟Account實體類我就不寫了
    public List<Trade> selectByTime(String a, Date time1, Date time2) {

        String sql = "select * from trade where accountid=? and TradeTime between ? and ? ";

        return this.temp.query(sql, new Object[] { a, time1, time2 },
                new RowMapper() {
                    public Object mapRow(ResultSet rs, int arg1)throws SQLException {
                        Trade t = new Trade();
                        t.setId(rs.getInt("id"));
                        Account a = new Account();
                        a.setAccountID(rs.getString("accountid"));
                        t.setAccount(a);
                        t.setTradeDigest(rs.getString("tradeDigest"));
                        t.setTradeMoney(rs.getDouble("tradeMoney"));
                        t.setTradeTime(rs.getDate("tradeTime"));
                        t.setTradeType(rs.getString("tradeType"));
                        return t;
                    }
                });
    }

    //查詢單個對象方法，Account實體類我就不寫了
    public Account selectRemaining(String aid) {

        String sql = "select * from Account where accountid=?";

        List list= this.temp.query(sql,new Object[] { aid },
                 new RowMapper() {
                    public Object mapRow(ResultSet rs, int arg1)
                            throws SQLException {
                        Account a = new Account();
                        a.setAccountID(rs.getString("accountid"));
                        a.setRemaining(rs.getDouble("remaining"));
                        return a;
                    }
                });

        if(list.size()==0){
            return null;
        }

        return (Account) list.get(0);
    }


    //修改方法,返回受影響的行數
    public int trade(String aid, double money) {

        String sql = "update account set remaining=remaining+? where accountid=? ";

        return this.temp.update(sql, new Object[] { money, aid });
    }

    //新增方法,返回受影響的行數(seq_trede.nextval數據庫序列,sysdate獲取當前系統時間)
    public int insertTrade(Trade t) {

        String sql = "insert into trade values(seq_trede.nextval,?,?,?,sysdate,?)";

        return this.temp.update(sql, new Object[] {t.getAccount().getAccountID(), 
                t.getTradeType(),t.getTradeMoney(), t.getTradeDigest() });
    }
}

//不通過JdbcTemplate對象操作

package util;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;

public class Template {


    // 針對任何表的查詢
    public void query(String sql, Object[] params) {
        Connection conn = null;
        PreparedStatement pst = null;
        ResultSet rs = null;
        conn = DBUtil.getConnection();//調用上面的DBUtil類中getConnection()方法獲取鏈接

        try {
            pst = conn.prepareStatement(sql);

            if (params != null) {
                for (int i = 0; i < params.length; i++) {
                    pst.setObject(i + 1, params[i]);
                }
            }
            rs = pst.executeQuery();

            //元數據類型
            ResultSetMetaData rsmd = rs.getMetaData();

            // 得到結果集共有幾列
            int count = rsmd.getColumnCount();

            while (rs.next()) {// 遍歷行

                for (int i = 0; i < count; i++) {

                    //我這裏在控制檯打印下,可以根據自己的需求封裝
                    System.out.print(rs.getObject(i + 1) + ",");

                }
                System.out.println();//打印換行
            }

        } catch (SQLException e) {

            e.printStackTrace();

        } finally {
            DBUtil.closeAll(conn, pst, rs);
        }
    }

    // 針對任何表的增，改，刪，返回受影響的行數
    // sql是要執行的SQL語句
    // Object[]保存的是SQL語句要用到的參數值
    public int update(String sql, Object[] params) {

        int rows = 0;//記錄受影響的行數
        Connection conn = null;
        PreparedStatement pst = null;
        conn = DBUtil.getConnection();//調用上面的DBUtil類中getConnection()方法獲取鏈接

        try {
            pst = conn.prepareStatement(sql);
            if (params != null) {
                for (int i = 0; i < params.length; i++) {
                    pst.setObject(i + 1, params[i]);
                }
            }

            rows = pst.executeUpdate();

        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            DBUtil.closeAll(conn, pst, null);
        }
        return rows;

    }



}