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);}
