JAVA中直接执行sql语句

获取数据库链接

    /**
     * @return
     * @throws Exception
     * @功能描述： 获取数据库连接
     */
    public static Connection getMySqlConnection(String url, String userName, String userPassword) throws Exception {
        Class.forName("com.mysql.cj.jdbc.Driver");
        return DriverManager.getConnection(url, userName, userPassword);
    }

执行select

 /**
     * 执行select
     * @param url 链接路径
     * @param username  用户名
     * @param password  密码
     * @param sql  sql语句
     * @return
     * @throws Exception
     */
    public static List<Map<String, Object>> executeGet(String url, String username, String password, String sql) throws Exception {
        Statement statement = null;
        ResultSet resultSet = null;
        try {
            Connection connection = getMySqlConnection(url,username,password);
            statement = connection.createStatement();
            resultSet = statement.executeQuery(sql);
            ResultSetMetaData metaData = resultSet.getMetaData();
            List<Map<String, Object>> resultList = new ArrayList<>();
            while (resultSet.next()) {
                Map<String, Object> dataMap = new HashMap<>();
                for (int i = 1; i <= metaData.getColumnCount(); i++) {
                    dataMap.put(metaData.getColumnLabel(i), resultSet.getObject(i));
                }                resultList.add(dataMap);
            }
            return resultList;
        } catch (Exception e) {
            throw e;
        } finally {
            try {
                if (resultSet != null) {
                    resultSet.close();
                }
                if (statement != null) {
                    statement.close();
                }
            } catch (SQLException e) {

            }
        }
    }

调用示例

    public static void main(String[] args) throws Exception {
        String url = "jdbc:mysql://IP地址:端口号/数据库名称?useUnicode=true&characterEncoding=utf8&zeroDateTimeBehavior=convertToNull&useSSL=true&serverTimezone=GMT%2B8";
        String username = "用户名";
        String pwd = "链接密码";
        String sql = "select data_code from gather_source;";

        List<Map<String,Object>> result = ExecuteUtil.executeGet( url, username, pwd, sql);
        //将结果转换成自己需要的格式
        String str = StringUtil.getSrting(result);

        System.out.println(str);
    }