自己封装了一个操作数据库的工具类以及通过资源文件获取数据库连接的类

布满荆棘的人生 2022-06-09 06:21 152阅读 0赞

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   <td><font> &nbsp;面向对象面向君，不负代码不负卿。 *^o^* </font> </td> 
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**欢迎大家指点**  
JDBCTools类(数据库操作工具类):

import java.sql.Connection;
    import java.sql.PreparedStatement;
    import java.sql.ResultSet;
    import java.sql.SQLException;
    import java.util.ArrayList;
    import java.util.List;
    
    /** * 数据库操作工具类 * * @author guixain * */
    public class JDBCTools { 
        /** * 执行删除操作 用法范例:String sql = "delete from user where id = ?" ; boolean flag =JDBCTools.update(sql, 1) ; * * @param sql sql语句 * @param o 删除的标志列 */
        public static Boolean delete(String sql, Object o) {
            Boolean flag = false;
            Connection conn = null;
            PreparedStatement ps = null;
            try {
                conn = DatabaseConnection.getConnection();
                ps = conn.prepareStatement(sql);
                ps.setObject(1, o);
                if (ps.executeUpdate() > 0) {
                    flag = true;
                }
            } catch (SQLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            JDBCTools.close(null, ps, conn);
            return flag;
        }
    
        /** * 修改操作 用法范例:String sql = "update user set username=?,password = ? ,balance = ? * where username = ?"; boolean flag = JDBCTools.update(sql, "奥拉fu", "233423",567, "Jerry"); * * @param sql sql语句 * @param args 修改的记录的列的参数 */
        public static boolean update(String sql, Object... args) {
            Boolean flag = false;
            PreparedStatement ps = null;
            Connection conn = null;
            try {
                conn = DatabaseConnection.getConnection();
                ps = conn.prepareStatement(sql);
                for (int i = 0; i < args.length; i++) {
                    ps.setObject(i + 1, args[i]);
                }
                if (ps.executeUpdate() > 0) {
                    flag = true;
                }
            } catch (SQLException e) {
                e.printStackTrace();
            }
            JDBCTools.close(null, ps, conn);
            return flag;
        }
    
        /** * 执行查找 用法范例: String sql = "select id,username,password,balance from user where * id like ?"; List<List<Object>> list = new ArrayList<>(); List<Object> list2 = null; list = JDBCTools.query(sql, 1); for (int i = 0; i < list.size(); i++) { list2 = list.get(i); for (int j = 0; j < list2.size(); j++) { System.out.println(i+1 + "属性:" + list2.get(j)); } } * * @param sql sql语句 * @return 结果集List里面存储了装了Object对象的List */
        public static List<List<Object>> query(String sql, Object... args) {
            PreparedStatement ps = null;
            ResultSet rs = null;
            Connection conn = null;
            List<List<Object>> list = new ArrayList<>();
            List<Object> list2 = null;
            try {
                conn = DatabaseConnection.getConnection();
                ps = conn.prepareStatement(sql);
                for (int i = 0; i < args.length; i++) {
                    if (sql.indexOf("like") != -1) {
                        ps.setObject(i + 1, "%" + args[i] + "%");
                    } else {
                        ps.setObject(i + 1, args[i]);
                    }
                }
                rs = ps.executeQuery();
                int m = rs.getMetaData().getColumnCount();
                while (rs.next()) {
                    list2 = new ArrayList<>();
                    for (int k = 0; k < m; k++) {
                        list2.add(rs.getString(k + 1));
                    }
                    list.add(list2);
                }
            } catch (SQLException e) {
                e.printStackTrace();
            }
            JDBCTools.close(rs, ps, conn);
            return list;
    
        }
    
        /** * 关闭相关操作 * * @param rs ResultSet 对象 * @param ps PreparedStatement 对象 * @param conn Connection 对象 */
        public static void close(ResultSet rs, PreparedStatement ps, Connection conn) {
            if (rs != null) {
                try {
                    rs.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }
            if (ps != null) {
                try {
                    ps.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }
            if (conn != null) {
                try {
                    conn.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }
        }
    }

DatabaseConnection(获取数据库连接类):

import java.io.InputStream;
    import java.sql.Connection;
    import java.sql.DriverManager;
    import java.sql.SQLException;
    import java.util.Properties;
    
    
    /** * 通过读取资源文件连接数据库的类 * @author guixain * */
    public class DatabaseConnection { 
        private static String driver ;
        private static String url ;
        public static String user ;
        public static String pass ;
        static {
            InputStream in = DatabaseConnection.class.getClassLoader()
                    .getResourceAsStream("JDBC.properties") ;
            Properties properties = new Properties() ;
            try {
                properties.load(in);
                driver = properties.getProperty("driver") ;
                url = properties.getProperty("url") ;
                user= properties.getProperty("user") ;
                pass = properties.getProperty("pass") ;
                Class.forName(driver) ;
            } catch (Exception e) {
                e.printStackTrace();
            }   
        }
        /** * 获取数据库连接 * @return Connection */
        public static Connection getConnection() {  
    
            Connection conn = null ;
            try {
                conn =  DriverManager.getConnection(url, user, pass) ;
            } catch (SQLException e) {
                e.printStackTrace();
            }
            return  conn;
    
        }
    }

JDBC.properties(资源文件):

driver = com.mysql.jdbc.Driver
    url = jdbc:mysql:///hgx?characterEncoding=utf-8
    user = root
    pass = 123456

<table> 
 <tbody> 
  <tr> 
   <td><font> &nbsp;&nbsp;&nbsp;大牛，别默默看了。快登陆帮我评论吧！ *^o^* </font> </td> 
  </tr> 
 </tbody> 
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